Agronomic performance and nutrient cycling in a maize-marandu grass rotation in response to the residual effect of composted sewage sludge applications

Abstract

Composted sewage sludge (CSS) contains considerable amounts of organic matter and plant nutrients and can be used as an organic fertilizer. A conservation tillage system, associated with CSS application, may provide sufficient nutrients to increase crop productivity. The objective of this study is to evaluate the residual effect of two annual CSS applications on nutrient cycling and its implications for: (i) maize nutrition, development, and crop yield, and (ii) biomass and nutrient accumulation by marandu grass, both cultivated in a Cerrado soil under no-tillage management. The experiment has been underway since 2017 in Selvíria/MS. A 4 × 2 + 2 factorial treatment structure in a randomized complete block design was implemented with the following treatments: i) CSS: 10, 15, 20, and 25 Mg ha-1 on a wet basis applied according to two different methods: whole area (WA) or between rows (BR); ii) comparison with two alternative treatments: a control with no CSS and mineral fertilizer application, an area treated with conventional fertilizers only. Soil samples will be collected at the end of each crop harvest to evaluate macro and micronutrient concentration and the following chemical attributes: OM, pH, CEC, H+Al, Al, SB, and BS. Mineral nutrition, some biometric parameters, and grain yield will be used to evaluate agronomic performance of maize. Nutrient cycling will be evaluated by biomass and nutrient accumulation marandu grass straw. The results obtained will be submitted to ANOVA and the means compared by the Tukey and Dunnet test, correlation, and polynomial regression, at the level of 5%.