Resumo

SANTILLANO CAZARES, Jesús et al. Soil fertility affects the growth, nutrition and yield of cotton cultivated in two irrigation systems and different nitrogen rates. Terra Latinoam [online]. 2019, vol.37, n.1, pp.7-14. ISSN 2395-8030.  https://doi.org/10.28940/tl.v37i1.304.

Intrinsic soil fertility and the method ofirrigation can affect the efficiency of nitrogen (N) fertilization, modify the yield goal, growth, and nutritional status of crops. A study was carried out with the objective of determining yield, growth, water use efficiency (WUE), agronomic efficiency of N (AEN), NO3- concentration in petiole cell extract (PCE) and chlorophyll index (SPAD) in a cotton crop by effect of N rates and two irrigation methods. The study consisted of two experiments established in soils of high fertility [˃13 g kg-1 organic matter (OM) and N-NO3- ˃ 30 mg kg-1], with varying N fertilization rates: a) flood irrigation (FRR, 11 and 220 kg N ha-1), and b) drip irrigation (FRG, 11 to 440 kg N ha-1). Plant height and number of nodes were not affected by the applied treatments. SPAD values and NO3- concentrations in PCE were cubically related to crop yield. The highest yield and WUE was obtained in the experiment with drip irrigation. In the FRR experiment no response (P > 0.05) to N fertilization treatments was found. In the FRG experiment, application of 440 kg N ha-1 reduced yield by 43% compared to the rest of the evaluated rates. AEN was statistically higher (P < 0.001) in treatments fertilized with 11 kg N ha-1. The low yield response due to application of N in cotton was attributed to high concentrations of N-NO3- and OM that are present in the soils in which the experiments were conducted.

Palavras-chave : fertigation; Gossypium hirsutum; mineral nutrition; nutrimental diagnostic.