Nitrogen-fertilized systems of maize intercropped with tropical grasses for enhanced yields and estimated land use and meat production

Authors: CRUSCIOL, CARLOS - Sao Paulo State University (UNESP); MATEUS, GUSTAVO - Sao Paulo State Agency For Agribusiness Technology (APTA); MOMESSO, LETUSA - Sao Paulo State University (UNESP); PARIZ, CRISTIANO - Sao Paulo State University (UNESP); CASTILHOS, ANDRE - Sao Paulo State University (UNESP); CALONEGO, JULIANO - Sao Paulo State University (UNESP); BORGHI, EMERSON - Sao Paulo State University (UNESP); COSTA, CINIRO - Sao Paulo State University (UNESP); Franzluebbers, Alan; CANTARELLA, HEITOR - Agronomical Institute Of Campinas (IAC)

Submitted to: Frontiers in Sustainable Food Systems
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/9/2020
Publication Date: 11/6/2020
Citation: Crusciol, C.A., Mateus, G.P., Momesso, L., Pariz, C.M., Castilhos, A.M., Calonego, J.C., Borghi, E., Costa, C., Franzluebbers, A.J., Cantarella, H. 2020. Nitrogen-fertilized systems of maize intercropped with tropical grasses for enhanced yields and estimated land use and meat production. Frontiers in Sustainable Food Systems. 4, Article 544853.

Interpretive Summary: Cropping system diversification is needed to pursue greater productivity, but also to overcome threats to ecological stability. Intercropping of forages with cereal grains has potential to diversity agricultural operations and close nutrient cycling to reduce losses of nutrients to the environment. A scientist with USDA Agricultural Research Service in Raleigh NC collaborated with a team of investigators from São Paulo State University and São Paulo Agency of Agribusiness Technology in Brazil to determine corn production with intercropping of tropical forage grasses as a source of forage for cattle consumption that would be ready for grazing during the winter dry season after corn grain harvest. Different nitrogen fertilization timings were applied to test if greater nitrogen availability early in the season was needed to overcome the competitive effects of the intercropped forage on corn grain yield, but that might also be needed for optimizing forage production. Early nitrogen fertilizer input was needed to maintain corn grain yield closer to that of monocropped corn. Intercropping systems were effective at increasing productivity and efficiently utilizing applied nitrogen more effectively. This research demonstrated the value of enhancing cropping systems diversity on agricultural productivity and points to potentially greater sustainability, by producing both cereal grain and livestock forage on the same land during the course of the year. This research will help farmers, extension specialists, and scientists to further refine cropping systems for greater sustainability.

Technical Abstract: Intercropping grain with forage crops bridges the gap between agriculture and sustainability. In tropical regions, forage grasses are increasingly being adopted as winter pasture intercropped and in rotation with maize to maximize food production. However, current recommendations for nitrogen (N) fertilizer application are based on monocropped maize (Zea mays), and the best N management approach for intercropping systems remains unclear. A 'eld experiment was carried out in three growing seasons with three intercropping systems [monoculture maize, intercropped with palisadegrass (Urochloa brizantha), and intercropped with guineagrass (Megathyrus maximus)] combined with six different split applications of N to maize (0-0, 100-0, 70-30, 50-50, 30-70, and 0-100 kg N/ha at seeding-sidedressing) with four replicates. We measured dry matter (DM) and accumulated N in maize and forage grasses, as well as maize production components and yields. Additionally, land equivalent ratio, relative crowding coef'cient, aggressivity of maize with forage grasses, forage crude protein (CP) concentration, estimated animal stocking rate, and estimated meat production and economic outcomes. Greatest maize yield was 8.7 Mg/ha for monocropped maize. However, favorable maize yield was also obtained in intercropping systems. Although no difference was observed between intercropping systems, applying all N at sidedressing of maize negatively affected maize and forage yields and, consequently, land use and economic evaluation. For both intercropping systems, estimated meat and land use were 114 and 10% higher when N fertilizer was applied than the control (0-0 kg N/ha), on average. Maize-forage grass intercropping is a viable alternative production system for improving yields and land use. In addition, estimated meat production and revenue can be enhanced with palisadegrass or guineagrass. At least half of the N fertilizer must be applied early in the growing season of maize to maximize production of maize to maximize production of the entire system.