Agri de Venezuela

Lara, Venezuela

Agri de Venezuela

Lara, Venezuela
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Torres P.L.,University Centroccidental Lisandro Alvarado | Aular J.,University Centroccidental Lisandro Alvarado | Rengel M.,Agri de Venezuela | Montano J.,Agri de Venezuela
Bioagro | Year: 2010

The fertilization of orange trees in Venezuela has been accomplished mainly by empirical forms or based in soil analysis. However, these procedures do not take into account all factors that affect nutrients absorption, and originate nutritional imbalances that may impair yield and quality of the fruits. In this research, the nutritional status of orange tree orchards located in the four main citrus zones of Yaracuy State (Aroa, Durute, Nirgua y Yumare) by analysis and DRIS-M diagnostic of 192 foliar samples, and later comparison with soil analysis. It was found that the main nutritional limitation is the phosphorus deficiency, followed by nitrogen excess, zinc deficiency, and iron excess. Potassium, magnesium, calcium and copper were generally in suitable proportions. Deficiencies of copper and manganese were found in Aroa, and only manganese in Nirgua. Some differences among the nutritional diagnoses of the four studied zones were detected. Possible causes of this diagnosis are discussed in the paper.


Rengel M.,Agri de Venezuela | Gil F.,Fundacana. Sector Central Matilde | Montano J.,Agri de Venezuela
Bioagro | Year: 2011

With the purpose of assessing the growth and macronutrient accumulation patterns of the sugar cane plant and promote a rational fertilization management of the crop, an evaluation was carried out in a plot cropped with the RB 85-5035 variety, in Chivacoa, Yaracuy State, Venezuela. The trial consisted on taking ten monthly samplings of the aerial portion of the plant, along the whole crop cycle. Each sample consisted of three stumps, taken at random in a surface of 0.6 m2 per stump, and dry biomass content and macronutrient concentrations were determined on both leaves and stalks. In the months 11 and 12, additional samples were taken to determine the final dry biomass. At the end of cycle the crop accumulated 43.7 t·ha-1 dry biomass, with 75.1 % corresponding to the stalks and the remaining to the leaves. The accumulation of N, P, K, Ca, Mg, and S at 300 days after cutting (dac) was 201,4; 43,2; 149,0; 112,7; 71,1 y 71,6 kg·ha-1, respectively. Nitrogen accumulated mainly in leaves during a good part of the cycle but at the end the nutrient was mainly translocated to the stems; it were found two critical periods of absorption, the first of which covered the stages of tillering and vegetative growth phase, and the second one was located at the stage of maturation of the reproductive phase. The nutrients P, K, Mg and S were proportionally distributed in leaves and stems for most of the crop cycle, but differed dramatically from 251 dac, when the accumulation was directed mainly towards the stem. Calcium was stored mainly in the leaves but at the end of the cycle the trend was reversed and the nutrient in the stems moderately exceeded that in the leaves. It was found that for the first four months of the plant growth the crop had produced just 16,5 % of its total biomass, but it had accumulated between 20 and 40 % of the macronutrients, which suggests the needs of their supply since the initial steps of the crop cycle.


Rengel M.,Agri de Venezuela | Gil F.,Fundacana. Sector Central Matilde | Montano J.,Agri de Venezuela
Bioagro | Year: 2011

With the purpose of determining the dynamics of micronutrient accumulation and partitioning of sugarcane var. RB 85-5035, a trial was conducted in Fundacaña, located in Chivacoa, Yaracuy State, Venezuela. Ten samples of the aerial part of the plant were taken through the growing season, and each sample consisted of three stumps, taken at random on a monthly basis in an area of 0.6 m2·cepa-1. Concentrations of Fe, Cu, Zn, Mn, B and Mo on stems and leaves were analyzed by Land Crop Laboratories in York, England. It was determined that the critical periods for micronutrient absorption are found in the vegetative phase and crop ripening. The micronutrients Fe, Mn, B and Mo were stored in greater amounts in the leaf tissue of the plant, while Cu and Zn accumulated more pronounced in the stems during the cycle. The accumulation patterns showed that the crop micronutrient requirements were: Fe=5241.5 g·ha-1, Cu=121.1 g·ha-1, Zn=875.6 g·ha-1, Mn=1142.4 g·ha-1, B=116.4 g·ha-1 and Mo=33.4 g·ha-1.

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