Agronomic characteristics of soybean under the production and decomposition of sunflower and Paiaguas palisadegrass biomass in different integrated production systems

Abstract

With the adoption of integrated production systems, relative gains in soybean yield have been achieved due to the permanence of vegetal residues on the soil surface. These residues favour the soil microbiota responsible for the decomposition of organic matter and nutrient cycling, which makes integrated agrosystems sustainable. The objective of this study was to evaluate the agronomic characteristics of soybeans under the production and decomposition of sunflower and Paiaguas palisadegrass biomass in different integrated production systems. The experiment was conducted off season in a dystroferric Red Latosol soil in a randomized block experimental design with four replicates. The treatments consisted of the following forage systems: monocropped sunflowers; monocropped Paiaguas palisadegrass; row sunflowers x Paiaguas palisadegrass; inter-row sunflowers x Paiaguas palisadegrass; and oversown sunflowers x Paiaguas palisadegrass. The results showed that the monocropped sunflower and Paiaguas palisadegrass presented the highest biomass production throughout the soybean development cycle, with the slowest decomposition, representing a strategy to increase soil cover efficiency mainly in the period prior to summer planting. The soybean cultivated in the biomass of the monocropped Paiaguas palisadegrass and the Paiaguas palisadegrass intercropped in rows and in inter-rows presented better yields and was positively influenced by the production parameters compared with soybean cultivated otherwise. Therefore, sunflower intercropped with Paiaguas palisadegrass during the off season in the Central-West Region of Brazil was shown to be a promising and sustainable cultivation technique for the production of biomass for no-tillage systems.

Soybean yield in integrated crop–livestock system in comparison to soybean–maize succession system

“…Higher soybean yield in integrated systems compared to maize in succession was also observed in the study by Dias et al (2020), showing the importance of using the excreta of animals as a nutrient return pathway, the protection of the soil by forage plants and better nutrient cycling for the soybean crop. Carvalho et al (2018) highlighted that areas without grazing, where vegetation serves the sole purpose of producing biomass for the no-till system in succession, do not produce more than grazed areas and that the introduction of the animal component into the system brings several benefits for nutrient recycling.…”

“…In integrated systems with tropical forages, it is possible to place animals into the area and utilize their excreta, which constitutes a nutrient return pathway to the soil (He et al, 2016), contributing to soil fertility and changing the dynamics of mineralization. It is also noteworthy that animal grazing stimulates the vigorous regrowth of forages, favouring growth for biomass production (Dias et al, 2020).…”

“…(2019) and Santos et al . (2020) showed that Paiaguas palisadegrass is one of the most suitable forages for crop–livestock integration, with satisfactory results in productivity, especially when water is scarce, and is an attractive option for biomass production (Costa et al ., 2016) and nutrient accumulation (Costa et al ., 2017) for soybean no-till systems (Oliveira et al ., 2020).…”

“…The N, P 2 O 5 and K 2 O fertilizer equivalents of the mulch biomass of the forage and maize cropping systems were determined considering the atomic mass of the elements according to analytical chemistry conventions and the N, P and K concentrations of the biomass analysed (Dias et al, 2020).…”

“…For the success of the integrated crop-livestock system, it is necessary to choose the forages most adapted to the edaphoclimatic conditions of the region, considering a balance between forage quality and yield. Currently, in Brazil, the most commonly used forage grasses in such systems are those of the genus Brachiaria (Guarnieri et al, 2019;Silva et al, 2019), and recently, due to the emergence of new Panicum maximum cultivars, this species has also been used (Machado et al, 2017;Dias et al, 2020). Thus, it is necessary to determine the potential of new forage species within integrated crop-livestock systems to produce forage in the off-season.…”