Chemical and biological attributes of soil and soybean (Glycine max) yield in integrated systems in the Cerrado of north-east Brazil

Context

Cultivation of forage grasses intercropped with maize (Zea mays) improves soil quality and yield of subsequent crops. However, for the Cerrado of north-east Brazil, little is known about the effects of this practice on soil chemical and biological attributes and on succeeding soybean crop’s yield and nutrition.

Aims

This study aimed to evaluate the influence of intercropping maize with forage grasses on soil chemical and biological properties and on the nutritional status and yield of succeeding soybean in the Cerrado of Piauí, Brazil.

Methods

In the 2016/2017 cropping season, maize (M) was grown in monoculture and intercropped with Megathyrsus maximus cvs Zuri, Massai, Tanzania, and Tamani; Urochloa brizantha cv. Marandu, and Urochloa ruziziensis cv. Ruziziensis. In the 2017/2018 and 2018/2019 cropping seasons, soybean (Glycine max) was grown on the same plots.

Key results

In the 2017/2018 cropping season, highest soil K concentrations in the 0–0.1 m depth were observed following M + Zuri and M + Massai. In the 2018/2019 cropping season, soybean grown after monoculture maize, M + Zuri, M + Tanzania and M + Ruziziensis promoted the highest soil basal respiration. Intercropping maize with forage grasses of the genus Urochloa increased the soil humic substances and carbon concentrations. The M + Tanzania treatment increased soybean leaf P and K concentrations in the 2017/2018 cropping season.

Conclusions

Intercropping maize with forage grasses improved soil fertility and increased cumulative soybean grain yield by 15%.

Implications

Maize intercropped with forage grasses, especially of the genus Urochloa, increases humic fractions and total soil organic carbon, and is thus a feasible agricultural management.