Biomass and protein in ruzigrass intercropped with maize subjected to plant densities and nitrogen fertilization

Abstract

The objective of this work was to evaluate the impacts of nitrogen topdressing fertilization and plant density of second-crop maize on the biomass and crude protein production of ruzigrass (Urochloa ruziziensis) grown in intercropping. The experiment was carried out during two growing seasons in a randomized complete block design, in split plots, with four replicates. The treatments consisted of N topdressing rates (0 and 80 kg ha^-1) and maize plant densities (40, 60, 80, and 100 thousand plants per hectare). Ruzigrass biomass accumulation was measured at the V14, R1, R3, and R6 stages of maize growth, as well as during ruzigrass desiccation. Ruzigrass crude protein content and production and biomass partitioning to leaves, stems, and senescent tissues were evaluated in the R6 stage of maize. The increase in maize plant density reduced ruzigrass growth. However, nitrogen fertilization and maize plant density did not affect ruzigrass biomass partitioning. During intercropping, N fertilization did not affect ruzigrass yield. After maize harvest, N fertilization resulted in a higher ruzigrass biomass (30.2% in 2019) and crude protein (13.8%) production. Low maize plant densities and N topdress fertilization improve the biomass production of ruzigrass in intercropping.