<?xml version="1.0" encoding="ISO-8859-1"?><article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<front>
<journal-meta>
<journal-id>0123-4226</journal-id>
<journal-title><![CDATA[Revista U.D.C.A Actualidad & Divulgación Científica]]></journal-title>
<abbrev-journal-title><![CDATA[rev.udcaactual.divulg.cient.]]></abbrev-journal-title>
<issn>0123-4226</issn>
<publisher>
<publisher-name><![CDATA[Universidad de Ciencias Aplicadas y Ambientales]]></publisher-name>
</publisher>
</journal-meta>
<article-meta>
<article-id>S0123-42262013000100014</article-id>
<title-group>
<article-title xml:lang="en"><![CDATA[DRIS NORMS FOR THE RUBBER CLONE FX3864 IN THE EASTERN PLAINS OF COLOMBIA]]></article-title>
<article-title xml:lang="es"><![CDATA[NORMAS DRIS PARA CAUCHO CLON FX3864 EN LOS LLANOS ORIENTALES DE COLOMBIA]]></article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Chacón-Pardo]]></surname>
<given-names><![CDATA[Edinson]]></given-names>
</name>
<xref ref-type="aff" rid="A01"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Camacho-Tamayo]]></surname>
<given-names><![CDATA[Jesús H.]]></given-names>
</name>
<xref ref-type="aff" rid="A02"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Bernal]]></surname>
<given-names><![CDATA[Jaime H.]]></given-names>
</name>
<xref ref-type="aff" rid="A03"/>
</contrib>
</contrib-group>
<aff id="A01">
<institution><![CDATA[,Universidad Pedagógica y Tecnológica de Colombia UPTC Facultad de Ciencias Agropecuarias ]]></institution>
<addr-line><![CDATA[ ]]></addr-line>
</aff>
<aff id="A02">
<institution><![CDATA[,Universidad Nacional de Colombia Programa de Ingeniería Agrícola ]]></institution>
<addr-line><![CDATA[ ]]></addr-line>
</aff>
<aff id="A03">
<institution><![CDATA[,Corporación Colombiana de Investigación CORPOICA C.I. La Libertad ]]></institution>
<addr-line><![CDATA[ ]]></addr-line>
</aff>
<pub-date pub-type="pub">
<day>30</day>
<month>06</month>
<year>2013</year>
</pub-date>
<pub-date pub-type="epub">
<day>30</day>
<month>06</month>
<year>2013</year>
</pub-date>
<volume>16</volume>
<numero>1</numero>
<fpage>113</fpage>
<lpage>120</lpage>
<copyright-statement/>
<copyright-year/>
<self-uri xlink:href="http://www.scielo.org.co/scielo.php?script=sci_arttext&amp;pid=S0123-42262013000100014&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.co/scielo.php?script=sci_abstract&amp;pid=S0123-42262013000100014&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.co/scielo.php?script=sci_pdf&amp;pid=S0123-42262013000100014&amp;lng=en&amp;nrm=iso"></self-uri><abstract abstract-type="short" xml:lang="en"><p><![CDATA[The present study aimed to establish the preliminary diagnosis and recommendation integrated system (DRIS) norms for the rubber tree clone FX3864 (Hevea brasiliensis) under the conditions of the Colombian Eastern Plains for the elements N, P, K, Ca, Mg, Na, S, Fe, Cu, Zn and B. For this purpose, 77 foliar samples were taken from a 10- to 12-year-old commercial crop. The element ratios that contributed the greatest variance between high- and low- productivity populations were selected for conversion into norms. Of the 132 possible ratios, 66 were selected, with ratios including P/N, N/K and NXCa proving most important. The most limiting nutrients were K and N when deficient and Ca and S when in excess.]]></p></abstract>
<abstract abstract-type="short" xml:lang="es"><p><![CDATA[El objetivo del presente trabajo fue obtener las normas preliminares de diagnóstico y recomendación integral DRIS para el cultivo de caucho clon FX3864 (Hevea brasiliensis) bajo condiciones de la altillanura colombiana para los elementos N, P, K, Ca, Mg, Na, S, Fe, Cu, Zn y B, para ello se tomaron 77 muestras de tejido foliar de plantaciones comerciales con edades entre 10 y 12 años. Para la selección de las relaciones que se convirtieron en normas se utilizó el método de mayor relación entre varianzas entre la población de baja productividad sobre la de alta productividad. De las 132 relaciones posibles se seleccionaron 66, destacándose relaciones como P/N, N/K, NXCa. El nutriente más limitante es el K seguido del N por defecto y el Ca seguido del S por exceso.]]></p></abstract>
<kwd-group>
<kwd lng="en"><![CDATA[Foliar analysis]]></kwd>
<kwd lng="en"><![CDATA[mineral nutrition]]></kwd>
<kwd lng="en"><![CDATA[diagnosis and recommendation]]></kwd>
<kwd lng="en"><![CDATA[fertilization]]></kwd>
<kwd lng="es"><![CDATA[Análisis foliar]]></kwd>
<kwd lng="es"><![CDATA[nutrición mineral]]></kwd>
<kwd lng="es"><![CDATA[diagnóstico y recomendación]]></kwd>
<kwd lng="es"><![CDATA[fertilización]]></kwd>
</kwd-group>
</article-meta>
</front><body><![CDATA[  <font size="2" face="Verdana">     <p align=right><b>CIENCIAS AGROPECUARIAS-Art&iacute;culo Cient&iacute;fico</b></p>     <p align="center"><b>DRIS NORMS  FOR THE RUBBER CLONE FX3864 IN THE EASTERN  PLAINS OF COLOMBIA</b></p>     <p align="center"><b>NORMAS DRIS PARA CAUCHO CLON FX3864 EN LOS LLANOS ORIENTALES DE COLOMBIA</b></p>     <p><b>Edinson Chac&oacute;n-Pardo<sup>1</sup>, Jes&uacute;s  H. Camacho-Tamayo<sup>2</sup>*, Jaime  H. Bernal<sup>3</sup></b></p>     <p><sup>1</sup> I.A., M.Sc. Universidad Pedag&oacute;gica y Tecnol&oacute;gica  de Colombia, Facultad  de Ciencias Agropecuarias, Grupo de Investigaciones Agr&iacute;colas, Tunja, Colombia. E-mail: <a href="mailto:echaconp@unal.edu.co">echaconp@unal.edu.co</a></p>     <p><sup>2</sup> I. Agr&iacute;cola, M.Sc. Profesor Asistente. Facultad  de Ingenier&iacute;a, Programa de Ingenier&iacute;a Agr&iacute;cola, Universidad Nacional de Colombia.  Cra. 45 No. 45 - 03, Bogot&aacute;,  Colombia.  E-mail: <a href="mailto:jhcamachot@unal.edu.co">jhcamachot@unal.edu.co</a> *Corresponding author</p>     <p><sup>3</sup>Corporaci&oacute;n  Colombiana  de Investigaci&oacute;n Agropecuaria - CORPOICA, C.I. La Libertad, Villavicencio, Colombia. E-mail: <a href="mailto:jbernal@corpoica.org.co">jbernal@corpoica.org.co</a></p>     <p>Rev. U.D.C.A Act. &amp; Div. Cient. 16(1): 113 - 120, 2013</p> <hr>     <p><b>SUMMARY</b></p>     ]]></body>
<body><![CDATA[<p>The present  study aimed to establish the preliminary diagnosis and recommendation integrated  system (DRIS) norms for the rubber tree clone FX3864 (<i>Hevea brasiliensis</i>)  under the conditions  of the Colombian  Eastern Plains for the elements  N, P, K, Ca, Mg, Na, S, Fe, Cu, Zn and B. For this purpose,  77 foliar samples  were taken from a 10- to 12-year-old commercial crop.  The element  ratios that contributed the greatest variance between high- and low- productivity populations  were selected  for conversion into norms. Of the 132 possible ratios, 66 were selected,  with ratios including P/N, N/K and NXCa proving most  important.  The most  limiting nutrients were K and N when deficient and Ca and S when in excess.</p>     <p><b>  Key words:</b> Foliar analysis, mineral  nutrition,  diagnosis  and recommendation, fertilization.</p> <hr>     <p><b>RESUMEN</b></p>     <p>El objetivo del presente  trabajo fue obtener  las normas  preliminares de diagn&oacute;stico  y recomendaci&oacute;n integral DRIS para el cultivo de caucho clon FX3864 (<i>Hevea brasiliensis</i>)  bajo condiciones de la altillanura colombiana para los elementos N, P, K, Ca, Mg, Na, S, Fe, Cu, Zn y B, para ello se tomaron  77 muestras de tejido foliar de plantaciones comerciales con edades  entre  10  y 12  a&ntilde;os.  Para  la selecci&oacute;n  de  las relaciones  que  se convirtieron en normas  se utiliz&oacute; el m&eacute;todo  de mayor relaci&oacute;n entre varianzas entre la poblaci&oacute;n  de baja productividad  sobre  la de alta productividad.  De las 132 relaciones posibles se seleccionaron 66, destac&aacute;ndose relaciones como P/N, N/K, NXCa. El nutriente m&aacute;s limitante es el K seguido del N por defecto y el Ca seguido del S por exceso.</p>     <p> <b> Palabras  clave:</b> An&aacute;lisis foliar, nutrici&oacute;n mineral, diagn&oacute;stico  y recomendaci&oacute;n, fertilizaci&oacute;n.</p> <hr>     <p><b>INTRODUCTION</b></p>     <p>The  eastern  plains  of Colombia  extend  from  the  town  of Puerto L&oacute;pez (Meta) to the source  of the Orinoco River. This area has a high agricultural potential,  with an estimated 4.5 million potentially arable  hectares (Rivas <i>et al. </i>2004).  Agricultural projects  are being developed  in the region with the hope  of introducing  crops  such  as soybean,  sugarcane, oil palm and rubber, among  others,  as alternative crops for owners of both small and large farms.</p>     <p>   In this region, rubber is principally found in the municipality of Puerto L&oacute;pez, where there are commercial plantations  in the productive and (primarily) growing stages.  These plantations  are managed at the nutritional level with fertilizer applications based on  research  from countries  such  as  Malaysia, Brazil and India (DANE, 2010). This previous research  was specific to the production zones in which it was conducted, and  its applicability depends on the clone type, plant population, soil characteristics and  environmental  resources of the  plantation. Therefore,  although  production in the eastern  plains of Colombia is not low (approximately 1800 kg ha<sup>-1 </sup>y r<sup>-1</sup>), it could be improved by determining  the specific fertilization requirements  for the particular soil conditions  of the area.</p>     <p>   The   diagnosis   and   recommendation   integrated    system (DRIS) is a tool for correctly interpreting  foliar analysis under these conditions.  DRIS was proposed by Beaufils (1973), based  on research  into plant physiology and nutrition, as an alternative to the nutritional evaluation of crops.  In contrast to  approaches such  as  the  critical-value or  range-of-sufficiency methods, DRIS is based  on the utilization of nutrient ratios instead of absolute  or individual concentrations. Some  ratios among  nutrients are more important  than others  for a specific crop, and these can be identified in high-productivity populations  when compared to low-productivity populations, which nonetheless also occasionally display ideal or optimal ratios, as reported  by Wadt &amp; Dias (2012).</p>     <p>   DRIS was initially developed  using rubber  crops  in Vietnam, and subsequent refinements  of the method  were conducted in  sugar  cane  and  corn  crops  in South  Africa by Beaufils (1973).  At present,  DRIS norms  have  been  developed  for crops such as roses,  coffee, apples and citrus fruits, among  others (Nachtigall &amp; Dechen,  2007).</p>     ]]></body>
<body><![CDATA[<p>   The  DRIS method   studies  nutrient  concentrations in  the leaves of a crop  to establish  the interactions  between  pairs of nutrients,  then  uses  the interactions  observed  in a highyielding population  as references  to develop norms  (Mour&atilde;o Filho, 2004).  This method  is based  on the estimation  of an index for each  pair of nutrients  (Dias <i>et  al</i>.  2010a).  DRIS norms are used for the nutritional evaluation of a low-yielding population,  employing  mathematical formulas  derived from different DRIS functions (Beaufils, 1973; Jones, 1981; Wadt <i>et al</i>. 2007).</p>       <p>  DRIS has advantages over other diagnostic methods because it generates an easily interpreted  continuous scale, allows for the  classification of nutrients  from the most  deficient to the most excessive, detects cases of yield limitation due to nutrient imbalances (including when no nutrients are below the critical level) and  allows for a total nutritional diagnosis  of the plant through  the nutritional balance index (Huang <i>et al. </i>2012).</p>     <p>   Once the norms are established, DRIS indices are calculated  for each nutrient. A negative index signifies that the element  in question  is deficient; if the index is positive, the element  is present  in excess;  and  if the index is near zero, the nutrient is  present  at  an  adequate or  balanced   level in the  plant. The  present   study  aims  to  establish  the  DRIS norms  for the rubber  crop clone FX 3864  under  the conditions  of the eastern  plains of Colombia.</p>     <p><b>MATERIALS AND METHODS</b></p>     <p><b>Study area. </b>The study was conducted in the town of Puerto L&oacute;pez in the  province  of Meta, Colombia,  in a 10-year-old  commercial  rubber   plantation   located   at  40&deg;5'46''N,  72&deg;57'30''W and an altitude of 184 m. The soil is an Inseptic Hapludox,  characterized by a high aluminum  saturation  and a low base saturation.  The predominant texture is sandy loam.  The chemical  characteristics of the soil are shown in <a href="#t1">table 1.</a></p>     <p><a name="t1"></a></p>    <p align="center"><img src="img/revistas/rudca/v16n1/v16n1a14t1.jpg"></p>     <p>   <b>Foliar and yield sampling. </b>During the month  of July 2010, recently matured  leaves from the  third medium  plant  were sampled.  Sampling  occurred  between  06:00  and  10:00  of each  day to reduce  diurnal nutritional variability, according  to the methodology proposed by Malavolta <i>et al. </i>(1997). In total, 80 samples  were taken. The samples  were prepared  by removing  the  petioles,  and  the  films were washed  with tap water and  dried in a cool environment  before being sent  to the laboratory.</p>     <p>   The  foliar samples   were  taken  to  the  laboratory  and,  by means  of dry digestion and atomic absorption, the elements  K,  Ca, Mg, Na, K, Fe, Cu, Mn and  Zn were determined. In a similar manner,  the colorimetric  method  was used  to determine  P and  B; as well as wet digestion  and  the Kjeldahl method  for N and turbidimetry for S.</p>     <p>   Three  latex measurements were conducted in the  field to establish  productivity.  These  measurements were taken  in June, September and December, coinciding with the periods of high, medium  and low precipitation, respectively, because the productivity of rubber is highly related to the water state of the plant (Ribeiro &amp; C&aacute;ssia, 2006).  These  measurements  were made  on the same  trees from which the foliar samples  were taken.</p>     ]]></body>
<body><![CDATA[<p>   Samples  without productivity information  or with a productivity of zero were eliminated from the study. Information regarding the planting date, area and production of each of the remaining analyzed lots was compiled.</p>     <p>   <b>Data   analysis</b>.    Populations    were   separated  using   the descriptive statistics described by Wadt <i>et al</i>. (1999): samples  in the highest quartile of productivity, averaged over the three latex  measurements,  were  considered  to  represent   high productivity, and  those  below that  quartile were considered to represent  low productivity.</p>     <p><b>DRIS  norms. </b>After  the   populations   were  selected,   the coefficients of variation, minima,  maxima  and  variances  for each  element,  as well as the ratios between  each  element,  were  calculated   in  both   the   high-   and   low-productivity populations.  The element ratios that contributed the greatest  variance   between   high-  and   low-productivity  populations  were  selected  for conversion  into  norms,  as  proposed by Summer (1990), who stated  that</p>     <p>If &#91;s<sup>2</sup> (A/B)<sub>b</sub> / s<sup>2</sup> (A/B)<sub>r</sub>&#93;> &#91;s<sup>2</sup> (B/A)<sub>b</sub> / s<sup>2</sup> (B/A)r&#93;, then the norm and the relationship chosen ratio = A/B;</p>     <p>If &#91;s<sup>2</sup> (A/B)<sub>b</sub>/ s<sup>2</sup> (A/B)r&#93; &lt;&#91;s<sup>2</sup> (B/A)<sub>b</sub> / s<sup>2</sup> (B/A)r&#93;, then, the norm and the relationship chosen ratio = B/A;</p>     <p>where s<sup>2</sup> (A/B)<sub>r</sub> is the difference of the ratio between the variances of the concentrations of the nutrients A and B in the reference population (r) and s<sup>2</sup> (A/B)<sub>b</sub> is the difference of the ratio between the variances of the concentrations of the nutrients A and B in the low-productivity population (b).</p>     <p><b>Nutritional balance index.</b> The nutritional indices (NI) were calculated using the methodology proposed by Beaufils (1973):</p>     <p>If A/B &lt;a/b, then</p>     <p>f(A/B) = (A/B - a/b)/ sa/b x (a/b / A/B);</p>     <p>otherwise,</p>     ]]></body>
<body><![CDATA[<p>f(A/B) = (A/B - a/b)/ sa/b,</p> where f(A/B) is the DRIS function for any two nutrients (A and B), A/B is the ratio between nutrients A and B in the sample, a/b is the ratio between  nutrients  A and  B in the reference standard and sa/b is the standard deviation of ratio A/B from the reference standard.</p>     <p>   The sum  of the values for the modulus  of the NI of all nutrients  constituted the  nutritional  balance  index (NBI), and the nutrient  average  balance  index (IBNm) was obtained  by dividing this value by the number  of NBI nutrients according  to the  expression  IBNm = (lNI_A&l+  lNI_Bl + lNI_Cl+...+ lNI_Nl/n, using as samples  the averages  of the lowyield population  (Dias <i>et al</i>. 2011; S&aacute;nchez <i>et al. </i>2009).</p>     <p><b>RESULTS AND DISCUSSION</b></p>     <p><b>Foliar description  and population  separation.</b> The median  values of N and K were deficient, at 2.85% and 0.67%, respectively (<a href="#t2">Table 2</a>); the median value of P was at an adequate level of 0.27%. These  conclusions are based  on the values reported  by Pushparajah &amp; Teng (1972), who observed  that the content  of N in rubber leaves on the basis of dry mass  is between 3.30% and 3.70%, that of P is between 0.209% and 0.25% and that of K is between 1.30% and 1.60%.</p>     <p><a name="t2"></a></p>    <p align="center"><img src="img/revistas/rudca/v16n1/v16n1a14t2.jpg"></p>     <p>   After eliminating  those  samples  without complete  productivity information  from the database, 77 samples  remained, exhibiting a  normal  distribution.  The  medium  productivity of these  samples  was 1802.8  kg ha<sup>-1 </sup> y r<sup>-1</sup>, with a minimum of 392.0  kg ha<sup>-1 </sup>y r<sup>-1</sup> and  a maximum  of 3492.7  kg ha<sup>-1 </sup>yr<sup>-1</sup>. These results suggest  that the samples  adequately  represent  the variation of the study area, a requirement for the development of DRIS norms  (Maia, 2012).</p>     <p>   The most productive quartile, the high-productivity/reference population,  contained 19 of the 77 samples, with a minimum  production threshold  of 2183.4  kg ha<sup>-1 </sup>yr<span class="s4">-1 </span>(<a href="#t3">Table 3</a>); 58 ofthe 77 samples were below this threshold and made up the low-productivity population. This division meets the criterion of Reis Junior &amp;Monnerat (2003), who suggested that the high-productivity population should consist of at least 10% of the samples.</p>     <p><a name="t3"></a></p>    <p align="center"><img src="img/revistas/rudca/v16n1/v16n1a14t3.jpg"></p>     ]]></body>
<body><![CDATA[<p>The median nutrient concentrations of N, K, Ca and Mg, among others, were greater in the high-productivity population; concentrations were similar between populations for P and greater in the low-productivity population for B and S. Because foliar analysis was conducted at the peak of production, elements such as N, Ca and Mg may have been in greater demand for latex formation than the other elements in the study.</p>     <p>Nutrient concentrations for the high-yield population were, in general, lower than those reported by Flores <i>et al.</i> (2004) in a study conducted in Venezuela on the clones IAN 873, IAN 710 and FX 3864, with the exception of Ca. The levels detected in the present study were, however, in agreement  with those reported  by Bataglia <i>et al</i>. (1988) for rubber trees in Brazil, with a production level greater than 1500 kg ha<sup>-1 </sup>yr<sup>-1</sup>. Both that study and  the present  study reported  lower levels of N and P and higher levels of Mg than those  suggested by Pushparajah &amp; Teng (1972) to be adequate for the development  of rubber  in Malaysia. It must  be considered that,  according to the type of material and its genetics,  nutrient contents vary to greater  or lesser degrees  (Mendes <i>et al</i>. 2012), and although  previous studies  provide reference  levels, it is possible  that  plants  exhibit different nutrient  requirements depending on their different growing conditions  (Bataglia <i>et al</i>. 1998; Nguyen, 2013).</p>     <p>   <b>DRIS norms</b>.  The  respective  norms  of the  high- and  low- productivity  populations   were  determined  as  coefficients or  products, whichever was more  appropriate in each  case (<a href="#t4">Table 4</a>). The coefficients  of variation were highest  for the ratios involving Fe, Cu and  S. This result is due to the high coefficients of variation for these  elements  in the global database (<a href="#t2">Table 2</a>), a situation that is generally true for the determination  of DRIS norms,  as reported  by different authors  (Nachtigall &amp; Dechen,  2007). Flores <i>et al</i>. (2004) concluded  that this situation  does  not complicate the interpretation  of the norm,  as the coefficient values represent  the real variation  that  exists for the  nutrient  contents of rubber  populations with average yield.</p>       <p><a name="t4"></a></p>    <p align="center"><img src="img/revistas/rudca/v16n1/v16n1a14t4.jpg"></p>     <p>   The  norms   obtained   for  the  ratios  and  products  of  the elements   were  selected   based   on  which  contributed the greatest   variance  between   the  high-  and  low-productivity populations.  Of the  132  possible  ratios,  66  were selected,  with  ratios  including  P/N,  N/K  and   NXCa  proving  most important.  These  ratios  exhibited clear differences  with the results  of previous  research  on  rubber  trees  conducted by Flores <i>et al</i>. (2004): for example, the P/N ratio was 0.07 in the Flores study and 0.09 in the present  study, indicating greater quantities  of P for the  high-yield population  in the  present case. Bataglia &amp; Santos  (1999) concluded that low levels of P in the soil and  leaves negatively affect the productivity of rubber trees in soils of otherwise high fertility.</p>     <p>   For the N/K and  NXCa ratios, Flores <i>et al</i>. (2004) obtained  values of 6.67 and 1.07, respectively, whereas the values obtained in the present  study were 4.69 and 2.13, respectively. Norms can vary significantly from one region to another,  as has  been  previously reported  (Dias <i>et al. </i>2010b;  Partelli <i>et al. </i>2006).  Bolton  (1964)  acknowledged these  differences when he reported  that the N, P and  K standards for rubber obtained  in Vietnam were inadequate for application  in Ma- laysian  plantations  due  to their improper  balance  for high- production populations.</p>     <p>   The  ratios  involving K  in  the  present   study  were  either higher or lower than  those  reported  by Flores <i>et al</i>. (2004), depending on K's role as either a numerator or denominator, respectively. Higher levels of K overall were observed  in the leaves  of the  present  study,  a  difference  that  may  impact productivity.</p>     <p>   <b>Nutritional balance  index</b>. Once  the DRIS norms  were established,  the nutritional diagnosis  was conducted by calculating the DRIS indices for each nutrient (<a href="#t5">Table 5</a>) and establishing the nutritional balance  indices (NBI), grouping  them from the most to the least limiting and using as samples  the averages  of the low-yield population,  as has been  proposed for coffee (Wadt &amp; Dias, 2012),  cupua&ccedil;u (Dias <i>et al. </i>2011) and orange (Dias <i>et al. </i>2013) in the Brazilian Amazon region.</p>       <p><a name="t5"></a></p>    ]]></body>
<body><![CDATA[<p align="center"><img src="img/revistas/rudca/v16n1/v16n1a14t5.jpg"></p>     <p>   Wadt <i>et al</i>. (1999) and Wadt (2005) stated that if the NI of an element  is greater  than  the NBIm, it is possible to generate a productivity response by adjusting  levels of that  element.  Elements such as N and K, for example, would cause  higher productivity when added,  whereas the restriction of elements  such as S would lead to higher productivity.</p>     <p>   In addition, the nutritional balance  of the sample  was calculated, and the order of nutrients  in terms  of importance was K&gt;N&gt;Cu&gt;Zn&gt;Mg&gt;B&gt;Mn&gt;P&gt;Fe&gt;Na&gt;Ca&gt;S.</p>     <p>   These results suggest  that, for the case of the low-yield population, the most  limiting nutrients  were K and  N when deficient and Ca and S when in excess. These results are concordant with the levels found in the low-productivity population (<a href="#t3">Table 3</a>) and  support  the  results  of Bataglia <i>et al</i>. (1998), who found  that low contents of K and  high contents of Ca  induced deficiencies of K and N in rubber, respectively, negatively influencing its productivity.</p>     <p>   DRIS norms  were established for a rubber crop on the eastern plains of Colombia  based  on  66  nutrient  ratios.  These norms  supply a tool for interpreting the nutritional state of a rubber  crop based  on foliar analysis. The most  limiting element under  the study conditions  is K. The obtained  norms establish  the differences between  highand low-productivity populations,  indicating  which elements  and  factors  should be considered for future crop management.</p>     <p><b>Acknowledgements: </b>The authors  thank  the  "Ministerio de Agricultura  y Desarrollo  Rural"  of  Colombia  for  financial support  and  Mavalle S.A. for logistical support. <u>Conflicts of interest</u>:  The  manuscript was  prepared   and  reviewed with the participation  of all authors,  who declare  the absence of conflicts of interest  that jeopardize the validity of the results presented.</p>     <p><b>BIBLIOGRAPHY</b></p>     <!-- ref --><p>1.    BATAGLIA,  O.C.;  CARDOZO,  M.;  VISCAINO, C.M.  1988.   Situa&ccedil;&atilde;o   nutricional  de  seringais  produtivos  no  estado   de  S&atilde;o  Paulo.  Bragantia.   (Brazil)  47(1):109-123.    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=000070&pid=S0123-4226201300010001400001&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --></p>     <!-- ref --><p>   2.    BATAGLIA,  O.  C.; SANTOS, W. R. 1999.  Efeitos da aduba&ccedil;&atilde;o NPK na  fertilidade do  solo,  nutri&ccedil;&atilde;o  e crescimento da seringueira.  Rev. Bras. Ci&ecirc;nc. Solo. (Brazil). 23(4):881-890.    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=000072&pid=S0123-4226201300010001400002&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --></p>     <!-- ref --><p>   3.    BATAGLIA,  O.C.;  SANTOS,  W.R.;  IGUE, T.;  GONÃ‡ALVES, P.S. 1998.  Resposta  da seringueira  clone RRIM 600 &agrave; aduba&ccedil;&atilde;o NPK em solo Podz&oacute;lico Vermelho Amarelo. Bragantia.  57(2):367-377.    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=000074&pid=S0123-4226201300010001400003&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --></p>     <!-- ref --><p>   4.    BEAUFILS, E.R. 1973.  Diagnosis  and  recommendation integrated  system  (DRIS). University of Natal (Bloemfontein, South Africa). 132p.    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=000076&pid=S0123-4226201300010001400004&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --></p>     <!-- ref --><p>   5.    BOLTON,  J.   1964.   The  manuring   and   cultivation of <i>Hevea  brasiliensis</i>.   J.  Sci.  Fd.  Agric. (USA).  15(1):1-8.    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=000078&pid=S0123-4226201300010001400005&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --></p>     <!-- ref --><p>   6.    DANE - Departamento Administrativo Nacional de Estad&iacute;stica. 2010. Informe de resultados  del censo  de unidades  productoras de  plantaciones de  caucho  -UPPC.  DANE, Direcci&oacute;n  de  Regulaci&oacute;n,  Planeaci&oacute;n,   Estandarizaci&oacute;n   y  Normalizaci&oacute;n  (Colombia). 66p.    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=000080&pid=S0123-4226201300010001400006&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --></p>     <!-- ref --><p>   7.    DIAS, J.R.M.; PEREZ, D.V.; SILVA, L.M.; LEMOS, C.O.; WADT, P.G.S.  2010a.   Normas  DRIS para  cupua&ccedil;uzeiro  cultivado  em  monocultivo  e em  sistemas agroflorestais.  Pesq. Agropec. Bras. 45(1):64-71.    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=000082&pid=S0123-4226201300010001400007&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --></p>     <!-- ref --><p>   8.    DIAS, J.R.M.; WADT, P.G.S.; PEREZ, D.V.; SILVA, L.M.; LEMOS, C.O. 2011.  DRIS formulas  for evaluation of  nutritional  status  of cupua&ccedil;u trees.  Rev. Bras. Ci&ecirc;nc. Solo. (Brazil). 35(1):2083-2091.    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=000084&pid=S0123-4226201300010001400008&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --></p>     <!-- ref --><p>   9.    DIAS,   J.R.M.;   WADT,   P.G.S.;    SAMPAIO,  F.A.R.; PITTELKOW,  F.K.;   MIOTTI,  A.A.;  ROSA,  M.R.  2010b.   Estabelecimento  de  normas   DRIS  para cupua&ccedil;ueiro na  regi&atilde;o  amaz&ocirc;nica. Rev. Caatinga. (Brazil). 23(4):121-128.    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=000086&pid=S0123-4226201300010001400009&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --></p>     <!-- ref --><p>   10.  DIAS, J.R.M.; WADT, P.G.S.; TUCCI, C.A.F.; SANTOS, J.Z.L.; SILVA, S. V.  2013.  Normas  DRIS multivariadas para avalia&ccedil;&atilde;o do estado  nutricional de laranjeira â€˜Pera' no  estado   do  Amazonas.  Rev. Ci&ecirc;nc. Agron. (Brazil). 44(2):125-134.    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=000088&pid=S0123-4226201300010001400010&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --></p>     <!-- ref --><p>   11.  FLORES, J.A.; GARAY, V.J.; PE&Ntilde;A, C. 2004. Evaluaci&oacute;n Nutricional de Plantaciones de <i>Hevea  brasiliensis </i>Muell.   Arg.,  Sector   El  Pozo,  San   Fernando  de Atabapo,  Estado  Amazonas,  Venezuela.  Rev. For. Lat. (Venezuela). 19(2):83-107.    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=000090&pid=S0123-4226201300010001400011&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --></p>     <!-- ref --><p>   12.  HUANG, H.;  HU, C.X.; TAN, Q.;  HU, X.; SUN,  X.; Bi,  L.  2012.   Effects  of  Fe-EDDHA  application on  iron chlorosis  of citrus  trees  and  comparison of  evaluations   on   nutrient   balance   with  three approaches. Sci. Hortic. (USA). 146(1):137-142.    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=000092&pid=S0123-4226201300010001400012&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --></p>     <!-- ref --><p>   13.  JONES, W.W. Proposed  modifications of the diagnosis and recommendation integrated  system (DRIS) for interpreting  plant analyses.  Comm.  Soil Sci. Plant Anal., 12:785-794, 1981.    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=000094&pid=S0123-4226201300010001400013&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --></p>     <!-- ref --><p>   14.  MAIA, C.E. 2012.  Fertilization response likelihood for the interpretation  of leaf analyses. Rev. Bras. Ci&ecirc;nc. Solo. 36(2):437-445.    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=000096&pid=S0123-4226201300010001400014&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --></p>     <!-- ref --><p>   15.  MALAVOLTA, E.; VITTI, G. C.; OLIVEIRA, S. A. 1997.  Avalia&ccedil;&atilde;o   do   estado    nutricional    das    plantas: princ&iacute;pios e aplica&ccedil;&otilde;es. 2a. Edi&ccedil;&atilde;o. Potafos (Piracicaba,  Brazil). 319p.    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=000098&pid=S0123-4226201300010001400015&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --></p>     <!-- ref --><p>   16.  MENDES, A.D.R.; OLIVEIRA,  L.E.M.; NASCIMENTO, M.N.; REIS, K.L.; BONOME, L.T.S. 2012.  Concentra&ccedil;&atilde;o  e redistribui&ccedil;&atilde;o  de nutrientes  minerais  nos diferentes   est&aacute;dios   foliares  de  seringueira.   Acta Amaz. (Brazil). 42(4):525-532.    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=000100&pid=S0123-4226201300010001400016&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --></p>     <!-- ref --><p>   17.  MOUR&Atilde;O-FILHO, F.A.A. DRIS: 2004.  Concepts   and applications  on nutritional diagnosis  in fruit crops. Sci. Agric. (Brazil). 61(5):550-560.    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=000102&pid=S0123-4226201300010001400017&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --></p>     <!-- ref --><p>   18.  NACHTIGALL,  G.  R.;  DECHEN,  A. R.  2007.   DRIS norms  for evaluating the nutritional state  of apple tree. Sci. Agric. 64(3):282-287.    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=000104&pid=S0123-4226201300010001400018&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --></p>     <!-- ref --><p>   19.  NGUYEN, B.T. 2013.  Large-scale  altitudinal gradient of natural rubber production in Vietnam. Ind. Crop Prod. (USA). 41:31-40.    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=000106&pid=S0123-4226201300010001400019&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --></p>     <!-- ref --><p>   20.  PARTELLI, F.L.;   VIEIRA, H.D.;   MONNERAT,  P.H.; VIANA, A.P.  2006.   Estabelecimento  de   normas  DRIS em cafeeiro conilon org&Acirc;nico  e convencional  no estado  do Esp&iacute;rito Santo. Rev. Bras. Ci&ecirc;nc. Solo.  30(1):443-451.    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=000108&pid=S0123-4226201300010001400020&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --></p>     <!-- ref --><p>   21.  PUSHPARAJAH,  E.;   TENG,   T.K.   1972.    Factors  influencing   leaf   nutrient    levels   in   rubber.    In: Proceedings   of   the    R.R.I.M.  Malaya   Planters Conference,  Kuala Lumpur 1972. Rubber Research  Institute of Malaya, Kuala Lumpur. p.140-154.    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=000110&pid=S0123-4226201300010001400021&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --></p>     <!-- ref --><p>  22.  REIS J&Uacute;NIOR,  R.A.; MONNERAT, P.H.  2003.   DRIS norms  validation for sugarcane crop.  Pesq.  Agropec. Bras. 38(3):379-385.    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=000112&pid=S0123-4226201300010001400022&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --></p>     <!-- ref --><p>  23.  RIBEIRO, J.C.;  C&Aacute;SSIA, C.E.  2006.   Fotoss&iacute;ntese  e rela&ccedil;&otilde;es   h&iacute;dricas   de   duas   cultivares  jovens  de seringueira.  Rev. Bras. Bot. 29(4):701-708.    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=000114&pid=S0123-4226201300010001400023&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --></p>     <!-- ref --><p>   24.  RIVAS, L.; HOYOS, P.; AMEZQUITA, E.; MOLINA, D.L.  2004.  Manejo y uso de suelos  en la altillanura Colombiana.   An&aacute;lisis econ&oacute;mico de  una  estrategia  para  su  conservaci&oacute;n y mejoramiento: construcci&oacute;n de una capa arable. CIAT (Cali, Colombia). 9p.    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=000116&pid=S0123-4226201300010001400024&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --></p>     <!-- ref --><p>   25.  S&Aacute;NCHEZ, A.A.; CRUZ, J.G.;  Z&Eacute;REGA, L.; RODR&Iacute;GUEZ, O.;  DE  OLIVEIRA,  S.A.,  P&Eacute;REZ VIANEL, J.  2009. Normas  preliminares  DRIS desarrolladas para ca&ntilde;a de az&uacute;car a partir de un bajo n&uacute;mero  de muestras. Pesq. Agropec. Bras. 44(12):1700-1706.    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=000118&pid=S0123-4226201300010001400025&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --></p>     <!-- ref --><p>   26.  SUMMER,  M. 1990.  Advances  in the  use  and  Application  of Plant Analysis.Com. Soil Sci. Plant Anal. (USA). 21(13-16):1409-1430.    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=000120&pid=S0123-4226201300010001400026&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --></p>     <!-- ref --><p>   27.  WADT, P.G.S.  2005.  Relationships  between  soil class and  nutritional  status   of  coffee  plantations.   Rev. Bras. Ci&ecirc;nc. Solo. 29(2):227-234.    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=000122&pid=S0123-4226201300010001400027&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --></p>     <!-- ref --><p>   28.  WADT, P.G.S.;  DIAS, J.R.M. 2012.  Normas  DRIS regionais e inter-regionais na avalia&ccedil;&atilde;o nutricional de caf&eacute; Conilon. Pesq. Agropec. Bras. 47(6):822-830.    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=000124&pid=S0123-4226201300010001400028&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --></p>     <!-- ref --><p>   29.  WADT, P.G.S.; NOVAIS, R.F; ALVAREZ, H.H.; BRAGANCA, S.M. 1999.  Alternativas da aplica&ccedil;&atilde;o  do DRIS &aacute; cultura do caf&eacute; conilon (<i>Coffea canepora </i>Pierre). Sci. Agric. (Brazil). 56(1):83-92.    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=000126&pid=S0123-4226201300010001400029&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --></p>     <!-- ref --><p>   30.  WADT, P.G.S.; SILVA, D.J.; MAIA, C.E.; TOME JUNIOR, J.B.;   COSTA  PINTO,  P.A.;  MACHADO, P.L.O.A.  2007.  Modelagem  de fun&ccedil;&otilde;es  no c&aacute;lculo dos &iacute;ndices DRIS. Pesq. Agropec. Bras. 42(1):57-64.    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=000128&pid=S0123-4226201300010001400030&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --></p>     <p>   Received: 12 October  2012  Accepted: 6 February 2013</p>     <p>  </font>      ]]></body><back>
<ref-list>
<ref id="B1">
<label>1</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[BATAGLIA]]></surname>
<given-names><![CDATA[O.C.]]></given-names>
</name>
<name>
<surname><![CDATA[CARDOZO]]></surname>
<given-names><![CDATA[M.]]></given-names>
</name>
<name>
<surname><![CDATA[VISCAINO]]></surname>
<given-names><![CDATA[C.M.]]></given-names>
</name>
</person-group>
<article-title xml:lang="pt"><![CDATA[Situação nutricional de seringais produtivos no estado de São Paulo]]></article-title>
<source><![CDATA[Bragantia]]></source>
<year>1988</year>
<volume>47</volume>
<numero>1</numero>
<issue>1</issue>
<page-range>109-123</page-range></nlm-citation>
</ref>
<ref id="B2">
<label>2</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[BATAGLIA]]></surname>
<given-names><![CDATA[O. C.]]></given-names>
</name>
<name>
<surname><![CDATA[SANTOS]]></surname>
<given-names><![CDATA[W. R.]]></given-names>
</name>
</person-group>
<article-title xml:lang="pt"><![CDATA[Efeitos da adubação NPK na fertilidade do solo, nutrição e crescimento da seringueira]]></article-title>
<source><![CDATA[Rev. Bras. Ciênc. Solo.]]></source>
<year>1999</year>
<volume>23</volume>
<numero>4</numero>
<issue>4</issue>
<page-range>881-890</page-range></nlm-citation>
</ref>
<ref id="B3">
<label>3</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[BATAGLIA]]></surname>
<given-names><![CDATA[O.C.]]></given-names>
</name>
<name>
<surname><![CDATA[SANTOS]]></surname>
<given-names><![CDATA[W.R.]]></given-names>
</name>
<name>
<surname><![CDATA[IGUE]]></surname>
<given-names><![CDATA[T.]]></given-names>
</name>
<name>
<surname><![CDATA[GONÇALVES]]></surname>
<given-names><![CDATA[P.S.]]></given-names>
</name>
</person-group>
<article-title xml:lang="pt"><![CDATA[Resposta da seringueira clone RRIM 600 à adubação NPK em solo Podzólico Vermelho Amarelo]]></article-title>
<source><![CDATA[Bragantia]]></source>
<year>1998</year>
<volume>57</volume>
<numero>2</numero>
<issue>2</issue>
<page-range>367-377</page-range></nlm-citation>
</ref>
<ref id="B4">
<label>4</label><nlm-citation citation-type="book">
<person-group person-group-type="author">
<name>
<surname><![CDATA[BEAUFILS]]></surname>
<given-names><![CDATA[E.R.]]></given-names>
</name>
</person-group>
<source><![CDATA[Diagnosis and recommendation integrated system (DRIS)]]></source>
<year>1973</year>
<page-range>132</page-range><publisher-loc><![CDATA[Bloemfontein ]]></publisher-loc>
<publisher-name><![CDATA[University of Natal]]></publisher-name>
</nlm-citation>
</ref>
<ref id="B5">
<label>5</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[BOLTON]]></surname>
<given-names><![CDATA[J.]]></given-names>
</name>
</person-group>
<article-title xml:lang="en"><![CDATA[The manuring and cultivation of Hevea brasiliensis]]></article-title>
<source><![CDATA[J. Sci. Fd. Agric.]]></source>
<year>1964</year>
<volume>15</volume>
<numero>1</numero>
<issue>1</issue>
<page-range>1-8</page-range></nlm-citation>
</ref>
<ref id="B6">
<label>6</label><nlm-citation citation-type="book">
<collab>DANE - Departamento Administrativo Nacional de Estadística</collab>
<source><![CDATA[Informe de resultados del censo de unidades productoras de plantaciones de caucho -UPPC]]></source>
<year>2010</year>
<page-range>66</page-range><publisher-name><![CDATA[DANE]]></publisher-name>
</nlm-citation>
</ref>
<ref id="B7">
<label>7</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[DIAS]]></surname>
<given-names><![CDATA[J.R.M.]]></given-names>
</name>
<name>
<surname><![CDATA[PEREZ]]></surname>
<given-names><![CDATA[D.V.]]></given-names>
</name>
<name>
<surname><![CDATA[SILVA]]></surname>
<given-names><![CDATA[L.M.]]></given-names>
</name>
<name>
<surname><![CDATA[LEMOS]]></surname>
<given-names><![CDATA[C.O.]]></given-names>
</name>
<name>
<surname><![CDATA[WADT]]></surname>
<given-names><![CDATA[P.G.S.]]></given-names>
</name>
</person-group>
<article-title xml:lang="pt"><![CDATA[Normas DRIS para cupuaçuzeiro cultivado em monocultivo e em sistemas agroflorestais]]></article-title>
<source><![CDATA[Pesq. Agropec. Bras.]]></source>
<year>2010</year>
<volume>45</volume>
<numero>1</numero>
<issue>1</issue>
<page-range>64-71</page-range></nlm-citation>
</ref>
<ref id="B8">
<label>8</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[DIAS]]></surname>
<given-names><![CDATA[J.R.M.]]></given-names>
</name>
<name>
<surname><![CDATA[WADT]]></surname>
<given-names><![CDATA[P.G.S.]]></given-names>
</name>
<name>
<surname><![CDATA[PEREZ]]></surname>
<given-names><![CDATA[D.V.]]></given-names>
</name>
<name>
<surname><![CDATA[SILVA]]></surname>
<given-names><![CDATA[L.M.]]></given-names>
</name>
<name>
<surname><![CDATA[LEMOS]]></surname>
<given-names><![CDATA[C.O.]]></given-names>
</name>
</person-group>
<article-title xml:lang="en"><![CDATA[DRIS formulas for evaluation of nutritional status of cupuaçu trees]]></article-title>
<source><![CDATA[Rev. Bras. Ciênc. Solo.]]></source>
<year>2011</year>
<volume>35</volume>
<numero>1</numero>
<issue>1</issue>
<page-range>2083-2091</page-range></nlm-citation>
</ref>
<ref id="B9">
<label>9</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[DIAS]]></surname>
<given-names><![CDATA[J.R.M.]]></given-names>
</name>
<name>
<surname><![CDATA[WADT]]></surname>
<given-names><![CDATA[P.G.S.]]></given-names>
</name>
<name>
<surname><![CDATA[SAMPAIO]]></surname>
<given-names><![CDATA[F.A.R.]]></given-names>
</name>
<name>
<surname><![CDATA[PITTELKOW]]></surname>
<given-names><![CDATA[F.K.]]></given-names>
</name>
<name>
<surname><![CDATA[MIOTTI]]></surname>
<given-names><![CDATA[A.A.]]></given-names>
</name>
<name>
<surname><![CDATA[ROSA]]></surname>
<given-names><![CDATA[M.R.]]></given-names>
</name>
</person-group>
<article-title xml:lang="pt"><![CDATA[Estabelecimento de normas DRIS para cupuaçueiro na região amazônica]]></article-title>
<source><![CDATA[Rev. Caatinga.]]></source>
<year>2010</year>
<volume>23</volume>
<numero>4</numero>
<issue>4</issue>
<page-range>121-128</page-range></nlm-citation>
</ref>
<ref id="B10">
<label>10</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[DIAS]]></surname>
<given-names><![CDATA[J.R.M.]]></given-names>
</name>
<name>
<surname><![CDATA[WADT]]></surname>
<given-names><![CDATA[P.G.S.]]></given-names>
</name>
<name>
<surname><![CDATA[TUCCI]]></surname>
<given-names><![CDATA[C.A.F.]]></given-names>
</name>
<name>
<surname><![CDATA[SANTOS]]></surname>
<given-names><![CDATA[J.Z.L.]]></given-names>
</name>
<name>
<surname><![CDATA[SILVA]]></surname>
<given-names><![CDATA[S. V.]]></given-names>
</name>
</person-group>
<article-title xml:lang="pt"><![CDATA[Normas DRIS multivariadas para avaliação do estado nutricional de laranjeira â€˜Pera' no estado do Amazonas]]></article-title>
<source><![CDATA[Rev. Ciênc. Agron.]]></source>
<year>2013</year>
<volume>44</volume>
<numero>2</numero>
<issue>2</issue>
<page-range>125-134</page-range></nlm-citation>
</ref>
<ref id="B11">
<label>11</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[FLORES]]></surname>
<given-names><![CDATA[J.A.]]></given-names>
</name>
<name>
<surname><![CDATA[GARAY]]></surname>
<given-names><![CDATA[V.J.]]></given-names>
</name>
<name>
<surname><![CDATA[PEÑA]]></surname>
<given-names><![CDATA[C.]]></given-names>
</name>
</person-group>
<article-title xml:lang="es"><![CDATA[Evaluación Nutricional de Plantaciones de Hevea brasiliensis Muell. Arg., Sector El Pozo, San Fernando de Atabapo, Estado Amazonas, Venezuela]]></article-title>
<source><![CDATA[Rev. For. Lat.]]></source>
<year>2004</year>
<volume>19</volume>
<numero>2</numero>
<issue>2</issue>
<page-range>83-107</page-range></nlm-citation>
</ref>
<ref id="B12">
<label>12</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[HUANG]]></surname>
<given-names><![CDATA[H.]]></given-names>
</name>
<name>
<surname><![CDATA[HU]]></surname>
<given-names><![CDATA[C.X.]]></given-names>
</name>
<name>
<surname><![CDATA[TAN]]></surname>
<given-names><![CDATA[Q.]]></given-names>
</name>
<name>
<surname><![CDATA[HU]]></surname>
<given-names><![CDATA[X.]]></given-names>
</name>
<name>
<surname><![CDATA[SUN]]></surname>
<given-names><![CDATA[X.]]></given-names>
</name>
<name>
<surname><![CDATA[Bi]]></surname>
<given-names><![CDATA[L.]]></given-names>
</name>
</person-group>
<article-title xml:lang="en"><![CDATA[Effects of Fe-EDDHA application on iron chlorosis of citrus trees and comparison of evaluations on nutrient balance with three approaches]]></article-title>
<source><![CDATA[Sci. Hortic.]]></source>
<year>2012</year>
<volume>146</volume>
<numero>1</numero>
<issue>1</issue>
<page-range>137-142</page-range></nlm-citation>
</ref>
<ref id="B13">
<label>13</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[JONES]]></surname>
<given-names><![CDATA[W.W.]]></given-names>
</name>
</person-group>
<article-title xml:lang="en"><![CDATA[Proposed modifications of the diagnosis and recommendation integrated system (DRIS) for interpreting plant analyses]]></article-title>
<source><![CDATA[Comm. Soil Sci. Plant Anal.]]></source>
<year></year>
<volume>12</volume>
<page-range>785-794</page-range></nlm-citation>
</ref>
<ref id="B14">
<label>14</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[MAIA]]></surname>
<given-names><![CDATA[C.E.]]></given-names>
</name>
</person-group>
<article-title xml:lang="en"><![CDATA[Fertilization response likelihood for the interpretation of leaf analyses.]]></article-title>
<source><![CDATA[Rev. Bras. Ciênc. Solo.]]></source>
<year>2012</year>
<volume>36</volume>
<numero>2</numero>
<issue>2</issue>
<page-range>437-445</page-range></nlm-citation>
</ref>
<ref id="B15">
<label>15</label><nlm-citation citation-type="book">
<person-group person-group-type="author">
<name>
<surname><![CDATA[MALAVOLTA]]></surname>
<given-names><![CDATA[E.]]></given-names>
</name>
<name>
<surname><![CDATA[VITTI]]></surname>
<given-names><![CDATA[G. C.]]></given-names>
</name>
<name>
<surname><![CDATA[OLIVEIRA]]></surname>
<given-names><![CDATA[S. A.]]></given-names>
</name>
</person-group>
<source><![CDATA[Avaliação do estado nutricional das plantas: princípios e aplicações]]></source>
<year>1997</year>
<edition>2a. Edição</edition>
<page-range>319</page-range><publisher-loc><![CDATA[Piracicaba ]]></publisher-loc>
<publisher-name><![CDATA[Potafos]]></publisher-name>
</nlm-citation>
</ref>
<ref id="B16">
<label>16</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[MENDES]]></surname>
<given-names><![CDATA[A.D.R.]]></given-names>
</name>
<name>
<surname><![CDATA[OLIVEIRA]]></surname>
<given-names><![CDATA[L.E.M.]]></given-names>
</name>
<name>
<surname><![CDATA[NASCIMENTO]]></surname>
<given-names><![CDATA[M.N.]]></given-names>
</name>
<name>
<surname><![CDATA[REIS]]></surname>
<given-names><![CDATA[K.L.]]></given-names>
</name>
<name>
<surname><![CDATA[BONOME]]></surname>
<given-names><![CDATA[L.T.S.]]></given-names>
</name>
</person-group>
<article-title xml:lang="pt"><![CDATA[Concentração e redistribuição de nutrientes minerais nos diferentes estádios foliares de seringueira]]></article-title>
<source><![CDATA[Acta Amaz.]]></source>
<year>2012</year>
<volume>42</volume>
<numero>4</numero>
<issue>4</issue>
<page-range>525-532</page-range></nlm-citation>
</ref>
<ref id="B17">
<label>17</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[MOURÁO-FILHO]]></surname>
<given-names><![CDATA[F.A.A.]]></given-names>
</name>
</person-group>
<article-title xml:lang="en"><![CDATA[Concepts and applications on nutritional diagnosis in fruit crops]]></article-title>
<source><![CDATA[Sci. Agric.]]></source>
<year>2004</year>
<volume>61</volume>
<numero>5</numero>
<issue>5</issue>
<page-range>550-560</page-range></nlm-citation>
</ref>
<ref id="B18">
<label>18</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[NACHTIGALL]]></surname>
<given-names><![CDATA[G. R.]]></given-names>
</name>
<name>
<surname><![CDATA[DECHEN]]></surname>
<given-names><![CDATA[A. R.]]></given-names>
</name>
</person-group>
<article-title xml:lang="en"><![CDATA[DRIS norms for evaluating the nutritional state of apple tree]]></article-title>
<source><![CDATA[Sci. Agric.]]></source>
<year>2007</year>
<volume>64</volume>
<numero>3</numero>
<issue>3</issue>
<page-range>282-287</page-range></nlm-citation>
</ref>
<ref id="B19">
<label>19</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[NGUYEN]]></surname>
<given-names><![CDATA[B.T.]]></given-names>
</name>
</person-group>
<article-title xml:lang="en"><![CDATA[Large-scale altitudinal gradient of natural rubber production in Vietnam]]></article-title>
<source><![CDATA[Ind. Crop Prod.]]></source>
<year>2013</year>
<volume>41</volume>
<page-range>31-40</page-range></nlm-citation>
</ref>
<ref id="B20">
<label>20</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[PARTELLI]]></surname>
<given-names><![CDATA[F.L.]]></given-names>
</name>
<name>
<surname><![CDATA[VIEIRA]]></surname>
<given-names><![CDATA[H.D.]]></given-names>
</name>
<name>
<surname><![CDATA[MONNERAT]]></surname>
<given-names><![CDATA[P.H.]]></given-names>
</name>
<name>
<surname><![CDATA[VIANA]]></surname>
<given-names><![CDATA[A.P.]]></given-names>
</name>
</person-group>
<article-title xml:lang="pt"><![CDATA[Estabelecimento de normas DRIS em cafeeiro conilon orgÂnico e convencional no estado do Espírito Santo]]></article-title>
<source><![CDATA[Rev. Bras. Ciênc. Solo.]]></source>
<year>2006</year>
<volume>30</volume>
<numero>1</numero>
<issue>1</issue>
<page-range>443-451</page-range></nlm-citation>
</ref>
<ref id="B21">
<label>21</label><nlm-citation citation-type="confpro">
<person-group person-group-type="author">
<name>
<surname><![CDATA[PUSHPARAJAH]]></surname>
<given-names><![CDATA[E.]]></given-names>
</name>
<name>
<surname><![CDATA[TENG]]></surname>
<given-names><![CDATA[T.K.]]></given-names>
</name>
</person-group>
<article-title xml:lang="en"><![CDATA[Factors influencing leaf nutrient levels in rubber]]></article-title>
<source><![CDATA[]]></source>
<year>1972</year>
<conf-name><![CDATA[ Proceedings of the R.R.I.M. Malaya Planters Conference]]></conf-name>
<conf-date>1972</conf-date>
<conf-loc>Kuala Lumpur </conf-loc>
<page-range>140-154</page-range></nlm-citation>
</ref>
<ref id="B22">
<label>22</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[REIS JÚNIOR]]></surname>
<given-names><![CDATA[R.A.]]></given-names>
</name>
<name>
<surname><![CDATA[MONNERAT]]></surname>
<given-names><![CDATA[P.H.]]></given-names>
</name>
</person-group>
<article-title xml:lang="en"><![CDATA[DRIS norms validation for sugarcane crop]]></article-title>
<source><![CDATA[Pesq. Agropec. Bras.]]></source>
<year>2003</year>
<volume>38</volume>
<numero>3</numero>
<issue>3</issue>
<page-range>379-385</page-range></nlm-citation>
</ref>
<ref id="B23">
<label>23</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[RIBEIRO]]></surname>
<given-names><![CDATA[J.C.]]></given-names>
</name>
<name>
<surname><![CDATA[CÁSSIA]]></surname>
<given-names><![CDATA[C.E.]]></given-names>
</name>
</person-group>
<article-title xml:lang="pt"><![CDATA[Fotossíntese e relações hídricas de duas cultivares jovens de seringueira]]></article-title>
<source><![CDATA[Rev. Bras. Bot.]]></source>
<year>2006</year>
<volume>29</volume>
<numero>4</numero>
<issue>4</issue>
<page-range>701-708</page-range></nlm-citation>
</ref>
<ref id="B24">
<label>24</label><nlm-citation citation-type="book">
<person-group person-group-type="author">
<name>
<surname><![CDATA[RIVAS]]></surname>
<given-names><![CDATA[L.]]></given-names>
</name>
<name>
<surname><![CDATA[HOYOS]]></surname>
<given-names><![CDATA[P.]]></given-names>
</name>
<name>
<surname><![CDATA[AMEZQUITA]]></surname>
<given-names><![CDATA[E.]]></given-names>
</name>
<name>
<surname><![CDATA[MOLINA]]></surname>
<given-names><![CDATA[D.L.]]></given-names>
</name>
</person-group>
<source><![CDATA[Manejo y uso de suelos en la altillanura Colombiana: Análisis económico de una estrategia para su conservación y mejoramiento: construcción de una capa arable]]></source>
<year>2004</year>
<page-range>9</page-range><publisher-loc><![CDATA[Cali ]]></publisher-loc>
<publisher-name><![CDATA[CIAT]]></publisher-name>
</nlm-citation>
</ref>
<ref id="B25">
<label>25</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[SÁNCHEZ]]></surname>
<given-names><![CDATA[A.A.]]></given-names>
</name>
<name>
<surname><![CDATA[CRUZ]]></surname>
<given-names><![CDATA[J.G.]]></given-names>
</name>
<name>
<surname><![CDATA[ZÉREGA]]></surname>
<given-names><![CDATA[L.]]></given-names>
</name>
<name>
<surname><![CDATA[RODRÍGUEZ]]></surname>
<given-names><![CDATA[O.]]></given-names>
</name>
<name>
<surname><![CDATA[DE OLIVEIRA]]></surname>
<given-names><![CDATA[S.A.]]></given-names>
</name>
<name>
<surname><![CDATA[PÉREZ VIANEL]]></surname>
<given-names><![CDATA[J.]]></given-names>
</name>
</person-group>
<article-title xml:lang="es"><![CDATA[Normas preliminares DRIS desarrolladas para caña de azúcar a partir de un bajo número de muestras]]></article-title>
<source><![CDATA[Pesq. Agropec. Bras.]]></source>
<year>2009</year>
<volume>44</volume>
<numero>12</numero>
<issue>12</issue>
<page-range>1700-1706</page-range></nlm-citation>
</ref>
<ref id="B26">
<label>26</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[SUMMER]]></surname>
<given-names><![CDATA[M.]]></given-names>
</name>
</person-group>
<article-title xml:lang="en"><![CDATA[Advances in the use and Application of Plant Analysis.Com.]]></article-title>
<source><![CDATA[Soil Sci. Plant Anal.]]></source>
<year>1990</year>
<volume>21</volume>
<numero>13-16</numero>
<issue>13-16</issue>
<page-range>1409-1430</page-range></nlm-citation>
</ref>
<ref id="B27">
<label>27</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[WADT]]></surname>
<given-names><![CDATA[P.G.S.]]></given-names>
</name>
</person-group>
<article-title xml:lang="en"><![CDATA[Relationships between soil class and nutritional status of coffee plantations]]></article-title>
<source><![CDATA[Rev. Bras. Ciênc. Solo.]]></source>
<year>2005</year>
<volume>29</volume>
<numero>2</numero>
<issue>2</issue>
<page-range>227-234</page-range></nlm-citation>
</ref>
<ref id="B28">
<label>28</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[WADT]]></surname>
<given-names><![CDATA[P.G.S.]]></given-names>
</name>
<name>
<surname><![CDATA[DIAS]]></surname>
<given-names><![CDATA[J.R.M.]]></given-names>
</name>
</person-group>
<article-title xml:lang="pt"><![CDATA[Normas DRIS regionais e inter-regionais na avaliação nutricional de café Conilon]]></article-title>
<source><![CDATA[Pesq. Agropec. Bras.]]></source>
<year>2012</year>
<volume>47</volume>
<numero>6</numero>
<issue>6</issue>
<page-range>822-830</page-range></nlm-citation>
</ref>
<ref id="B29">
<label>29</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[WADT]]></surname>
<given-names><![CDATA[P.G.S.]]></given-names>
</name>
<name>
<surname><![CDATA[NOVAIS]]></surname>
<given-names><![CDATA[R.F]]></given-names>
</name>
<name>
<surname><![CDATA[ALVAREZ]]></surname>
<given-names><![CDATA[H.H.]]></given-names>
</name>
<name>
<surname><![CDATA[BRAGANCA]]></surname>
<given-names><![CDATA[S.M.]]></given-names>
</name>
</person-group>
<article-title xml:lang="pt"><![CDATA[Alternativas da aplicação do DRIS á cultura do café conilon (Coffea canepora Pierre)]]></article-title>
<source><![CDATA[Sci. Agric.]]></source>
<year>1999</year>
<volume>56</volume>
<numero>1</numero>
<issue>1</issue>
<page-range>83-92</page-range></nlm-citation>
</ref>
<ref id="B30">
<label>30</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[WADT]]></surname>
<given-names><![CDATA[P.G.S.]]></given-names>
</name>
<name>
<surname><![CDATA[SILVA]]></surname>
<given-names><![CDATA[D.J.]]></given-names>
</name>
<name>
<surname><![CDATA[MAIA]]></surname>
<given-names><![CDATA[C.E.]]></given-names>
</name>
<name>
<surname><![CDATA[TOME JUNIOR]]></surname>
<given-names><![CDATA[J.B.]]></given-names>
</name>
<name>
<surname><![CDATA[COSTA PINTO]]></surname>
<given-names><![CDATA[P.A.]]></given-names>
</name>
<name>
<surname><![CDATA[MACHADO]]></surname>
<given-names><![CDATA[P.L.O.A.]]></given-names>
</name>
</person-group>
<article-title xml:lang="pt"><![CDATA[Modelagem de funções no cálculo dos índices DRIS]]></article-title>
<source><![CDATA[Pesq. Agropec. Bras.]]></source>
<year>2007</year>
<volume>42</volume>
<numero>1</numero>
<issue>1</issue>
<page-range>57-64</page-range></nlm-citation>
</ref>
</ref-list>
</back>
</article>
