Nitrogen fertilization in off-season corn crop in different Brazilian Cerrado environments

Abstract

The objective of this work was to assess the grain yield and the economic response of off-season corn (Zea mays) crop subjected to different combinations of starter and topdressing nitrogen fertilization, in the Brazilian Cerrado region. The experiment was carried out in a randomized complete block design in a 3×4 factorial arrangement (0, 45, and 90 kg ha-1 N at sowing and 0, 22.5, 45, and 90 kg ha-1 N in topdressing as urea), in six environments, combining three sites and two sowing times. Grain yield was determined, and the response to total N applied as starter and topdressing was used to obtain a general model of the average trend of the technical and economic return of fertilization. The corn crop response varied according to the environment, and the observed yields were high. The application of N as a starter fertilizer increased corn yield and improved the effect of topdressing fertilization or even made it unnecessary. Fertilization with 90 kg ha-1 N as urea promotes greater yield and economic return and improves N balance in the soybean/off-season corn crop system.

Closing the Gap: Sustainable Intensification Implications of Increased Corn Yields and Quality for Second-Crop (safrinha) in Mato Grosso, Brazil

“…Our average corn GY was 252% more than those for a 2006 dry-season study, averaged across three municipalities in MS at only 2967 kg/ha [57]. Compared to past experiments in Mato Grosso (MT) state, our GY for corn hybrids were 24.4 to 68.7% higher compared to experimental results from studies at the Brazilian Agricultural Research Corporation (Embrapa) Agrossilvipastoril research unit in Sinop, MT [55,58,59], which is ~150 km north of our cooperating farm. The recent statewide 2020 average safrinha corn GY for MT, Brazil, was 6392 kg/hectare [13], 38.9% lower than the average corn GY for the hybrids we evaluated.…”

“…Our average corn GY (10,457 kg/ha; Table 5) was 10.1 to 51.5% higher compared to past field experiments also conducted during the dry season in Minas Gerais [54], southwestern Goiás and eastern Rondônia [55], and Mato Grosso do Sul (MS) [56] states. Our average corn GY was 252% more than those for a 2006 dry-season study, averaged across three municipalities in MS at only 2967 kg/ha [57].…”

Understanding the contribution of soybean crop residues inoculated with Bradyrhizobium spp. and not harvested on nitrogen supply in off-season corn cultivars

“…The use of simple corn hybrids in off-season corn cultivation between January and May (after the summer soybean crop) has high yield potential in the Cerrado region. However, to express all this production potential, the application of high rates of N fertilizers is required [ 14 , 15 ]. In many situations, reduced rates of N fertilizers have been applied when off-season corn is grown after the soybean crop [ 16 ].…”

“…To adjust N fertilization for this crop succession in the Brazilian Cerrado region, it has been considered that each ton of soybean grain corresponds to 17 kg ha –1 of N in the crop residue, which is released for the subsequent corn crop [ 15 ]. Therefore, an average yield of 3.6 Mg ha –1 of soybeans would indicate a surplus of up to 61 kg ha –1 of N, which is insufficient to meet the N demand of off-season corn [ 14 ]. However, an issue that still needs to be understood is the proper management of N fertilization when corn is grown after unharvested soybeans.…”

“…Corn crops grown after unharvested soybeans can benefit from the fast and greater release of nutrients from decomposing legume crop residues, which have a low C/N ratio [ 15 ]. However, the N demand of the off-season corn crop depends on the cultivar, crop succession system, and the interaction of the genotype with the production environment [ 14 ]. For instance, the economically optimum N rate reported for off-season corn grown in the Cerrado region ranged from 40 to 180 kg ha −1 of N, depending on the production system and the year [ 14 , 15 , 18 – 20 ].…”