ABSTRACT
Knowing about the nutrient uptake during plant cycle is essential for nutrient management decisions. We evaluated dry matter accumulation and nutrient demand, and it to determine the uptake curves, the ideal phase for management, and element extraction order for yard long beans. The experiment was carried out in a greenhouse. The experimental design was completely randomized, with eight collection periods, at 10, 20, 30, 40, 50, 60, 70 and 80 days after emergence (DAE), and four replicates. For each period, destructive sampling was performed and the sample’s dry matter content was determined, so that it could be used to estimate macro- and micronutrient contents. When significant, nonlinear models were adjusted to explain dry matter accumulation and nutrient uptake. The sigmoidal equation was the model which best depicted the growth curve for yard long bean, which reached a maximum biomass accumulation of 177.5 g plant-¹ at 80 DAE. The crop's most demanding phase in terms of nutritional requirements is from 20 to 45 DAE, which is the ideal phase for nutrient management. The element extraction order at the end of the plant's cycle was K>Ca=N>S=P>Mg (macronutrients) with values of 2,668.3 mg plant-¹, 2,331.1 mg plant-¹, 2,279.2 mg plant-¹, 507.5 mg plant-¹, 496.3 mg plant-¹ and 213.2 mg plant-¹, and Fe>B>Zn>Mn>Cu (micronutrients), with 10,933.1 µg plant-¹, 6,310.8 µg plant-¹, 4,746.8 µg plant-¹, 2,854.1 µg plant-¹ and 717.1 µg plant-¹, respectively.
Keywords:
Vigna unguiculata susbp. sesquipedalis; macronutrient and micronutrient accumulation
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