Long-term wheat-soybean successions affecting the cover and soil management factor in USLE, under subtropical climate

Abstract

Vegetation cover and soil management influence the magnitude of soil losses. In the Universal Soil Loss Equation (USLE), cover and management are represented by the C factor, as it is the easiest factor to manage to reduce loss of soil and water in agricultural areas. This study aimed to determine the C factor of a succession of wheat (Triticum aestivum L.) followed by soybean (Glycine max) under conventional tillage, reduced tillage, and no-tillage. For this, data of soil losses obtained in the field, under natural rainfall conditions, in a long-term experiment that lasted for 13 years were used. The cycle of both crops was divided into five stages with different time intervals between winter and summer, which resulted in ten periods per year constituting the succession. The C factor values varied widely among the treatments and the stages during the crop cycle, and they were influenced mainly by the rainfall distribution of the region, growth of the vegetation and soil disturbance level. By the end of the 13 years of experimentation, the C factor of the wheat-soybean succession under conventional tillage was 0.1576, 0.0407 under reduced tillage, and 0.0368 under no-tillage.

Is cassava yield affected by inverting tillage, chiseling or additional compaction of no-till sandy-loam soil?

“…Soil chiseling is a tillage method used to reduce surface soil compaction in no-tillage systems by reducing soil bulk density and enhancing pore space (Cavalieri et al, 2006;Klein and Camara, 2007;Fasinmirin and Reichert, 2011;Awe et al, 2020;Reichert et al, 2020a;França et al, 2021;Reichert et al, 2021a;Rosa et al, 2021). Conventional tillage, the traditional tillage method used for cassava (Santos et al, 2020;Thomaz and Fidalski, 2020), is another option for decreasing soil compaction, but the excessive disturbance from soil inverting and mixing by plowing and disking causes undesirable effects such as soil disaggregation, with further exposion to rainfall impact (Lima et al, 2015), especially in sandy soils that are highly prone to erosion (Cantalice et al, 2005;Silva et al, 2020;Thomaz and Fidalski, 2020). In Brazil and elsewhere, the different tillage methods have been evaluated for soil compaction by quantifying the limiting soil bulk density and the performance of several crops (Suzuki et al, 2007;Reinert et al, 2008;Reichert et al, 2009a;Secco et al, 2009;Suzuki et al, 2013;Mentges et al, 2016;Moraes et al, 2019;Reichert et al, 2016aReichert et al, , 2017Reichert et al, , 2018Ambus et al, 2018;Andognini et al, 2020;Reichert et al, 2021a,b).…”