Influence of nitrogen forms and levels on the growth and nutrition of cacao |
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| Authors: | V C Baligar N K Fageria |
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| Institution: | USDA-ARS-Sustainable Perennial Research Lab, Beltsville, MD, USA |
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| Abstract: | Ammonium and nitrate are the major forms of nitrogen (N) present in tropical soils. An experiment was conducted to assess the influence of nitrate and ammonium forms (NO3?, NH4+, and mix of NO3? + NH4+), and levels (1.5–12.0 mM) of N on the growth and nutrition of cacao (Theobroma cacao L). Growth parameters were significantly influenced by N forms, and nitrogen supplied as NH4+ proved better for the growth of cacao compared with NO3? form and mixtures of these two forms. Irrespective of the forms of N, levels of N had no significant effect on plant growth parameters. Nutrient efficiency ratios (NERs) (shoot dry matter produced per unit of nutrient uptake) for macronutrients were sulfur>phosphorus>calcium>magnesium>nitrogen>potassium (S>P>Ca>Mg>N>K) and for micronutrients NERs were in the order of copper>boron>zinc>iron>manganese (Cu>B>Zn>Fe>Mn). |
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| Keywords: | NH4+ and NO3? forms of N root and shoot growth relative growth rate macro and micronutrients influx nutrient efficiency ratio |
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