PRECISION AGRICULTURE: VARIABLE PHOSPHORUS RATE IN SOYBEAN (Glycine max (L.) Merrill.)

Abstract

Precision agriculture (AP) allows differentiating management sites (ZM) that express
contrasting grain yield potential. The aims of this study were to: i) evaluate the interaction between ZM and phosphorus (P) fertilization over soybean yield, and ii)
quantify the P use efficiency (EUP) in the different ZM. The experience was carried out in
two agricultural fields (Site 4 and Site 6) from Benito Juárez. (37°26'53,23"S;
59°35'45,28"O). The ZM were delimited based on the land elevation, topographic index
(TWI) and soil depth. The extractable P content (P-Bray) was determined at each ZM after
soil sampling. At each ZM, trials with a randomized complete block design (four
replications) were performed to evaluate five different P rates (0, 10, 15, 20, 25 kg P ha-
1). No interaction between ZM and P fertilization over grain yield was observed. However,
the EUP was affected by ZM. The greatest EUP was observed in zones with medium or high
productive potential with lower values of P-Bray in the soil.