FONTES E DOSES DE NPK EM MILHO IRRIGADO SOB PLANTIO DIRETO
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e-ISSN 1983-4063 - www.agro.ufg.br/pat - Pesq. Agropec. Trop., Goiânia, v. 41, n. 2, p. 254-263, abr./jun. 2011FONTES E DOSES DE NPK EM MILHO IRRIGADO SOB PLANTIO DIRETO1
Márcio Valderrama2, Salatiér Buzetti2,
Cleiton Gredson Sabin Benett3, Marcelo Andreotti2, Marcelo Carvalho Minhoto Teixeira Filho2
ABSTRACT
NPK SOURCES AND DOSES
ON IRRIGATED CORN UNDER NO-TILL SYSTEM
RESUMO
Coated fertilizers can provide lower losses and higher soil nutrients availability, which can be absorbed by plants, when we consider their gradual release. The objective of this study was to evaluate the effect of doses and sources of N,
P, and K on maize grain components and yield, under no-till system, in the Brazilian savannah. The experimental design was randomized blocks, with 4 top-dressed doses (0 kg ha-1,
40 kg ha-1, 80 kg ha-1, and 120 kg ha-1) and 2 sources (urea and coated urea), for N; 4 doses (0 kg ha-1, 50 kg ha-1, 100 kg ha-1, and 150 kg ha-1) and 2 sources (triple superphosphate and coated triple superphosphate), for P; and 4 doses (0 kg ha-1, 40 kg ha-1,
80 kg ha-1, and 120 kg ha-1) and 2 sources (potassium chloride and coated potassium chloride), for K, with 4 replications. The fertilizers coated with polymers (urea, triple superphosphate, and potassium chloride) were not efficient under the soil and climate conditions studied, because they provided results similar to the same conventional fertilizers, for the N, P, and K foliar contents, and irrigated maize grain components and yield. The increment of N doses increased linearly the N leaf content, number of ears per hectare and maize grains yield. The application of K2O and
P2O5 doses did not influence grain yield.
A utilização de fertilizantes revestidos pode proporcionar menores perdas e maior disponibilidade de nutrientes no solo, passíveis de absorção pelas plantas, tendo em vista a liberação gradativa dos nutrientes. O objetivo deste trabalho foi avaliar o efeito de doses e fontes de N, P e K, nos componentes de