Soil physical properties and root activity in a soybean second crop/maize rotation under direct sowing and conventional tillage

Abstract

Soil degradation is the result of interactions involving the soil itself, human activity, climate, relief, and vegetation. These can lead to changes in —or even the loss of— certain characteristics of the soil, reducing its present and future productive capacity. The aim of this study was to determine the behaviour of a number of soil physical variables and total organic carbon content, as well as the root activity and yield of crops grown in rotation (soybean in 1998/1999 and maize in 1999/2000) under direct sowing (DS) and conventional tillage (CT) conditions. Root activity was assessed using an isotopic methodology involving the uptake of 32P. The root activity of the soybean crop, which grew under normal rainfall conditions, was greater under CT conditions. That of the maize crop, which grew when rainfall was well below normal, was greater under DS conditions. Bulk density was higher and total porosity lower in the upper 0.10 m of the soil in the DS plots. Conventional tillage led to lower penetration resistance values in the upper layers of the soil profile. No differences in soil total organic carbon were found between the two tillage systems. The soil water content of the upper soil layers was higher under DS. The yield of the soybean crop under CT was 57% higher than under DS. The yield of maize was affected by water deficiency; higher yields were obtained with DS than with CT.

Effect of tillage system on yield and weed populations of soybean ( Glycin Max L.)

“…The increase in seed yield with NT management may be due to improved soil structure and surface residue cover which enhance water infi ltration and root growth and/or reduce water losses through evaporation from the soil (Diaz-Zorita et al 2004, Tarkalson et al 2006). In contrast, Barrios et al (2006) observed significantly higher yields in soybean crops under conventional tillage than in no tillage system in a rotation maize/soybean. At the same time, Lança Rodrígues et al (2009) found no signifi cant differences in soybean seed yields among tillage systems.…”

Effects of different soil tillage systems and coverages on soybean crop in the Botucatu Region in Brazil

“…Although different characteristics of soybean have been previously studied in this or in a similar framework (Santos et al, 1994a;Barrios et al, 2006;Di Ciocco et al, 2008), reported results differed considerably depending on the considered trait. This fact may reflect a lack of suitability in certain culture traits in order to describe the effects of management techniques and coverages.…”

“…In addition, Kluthcouski et al (2000) observed the same between different tillage systems. However, Barrios et al (2006) observed significantly higher yields in soybean crops under CT than in NT systems in a rotation maize/soybean. Lopes et al (2007) found significantly higher yields in soybean crops under CT compared to NT depending on the previous cover used, which were different from the ones used in the current study.…”

“…This development is mainly related to agricultural machines in order to evaluate or increase their efficiency under different conditions (Camacho-Tamayo and Rodríguez, 2007;. Furthermore, as pointed out by Barrios et al (2006), agricultural scientists are searching for new ways to enhance crop production, reduce costs, and improve soil and water conservation while reducing the environmental impact of agriculture.…”

Atributos Físicos Do Solo E Crescimento De Raiz Da Soja Após Cultivos De Outono-Inverno

“…Os maiores valores de Mi observados nas profundidades de 0,0 -0,10 m e 0,30 -0,40 m (Tabela 2) possivelmente, é consequência da menor resistência à penetração do solo, pois nessas profundidades os valores de porosidade total também são maiores. As camadas intermediárias podem apresentar aumento na densidade do solo, visto que o acúmulo dos resíduos vegetais em SPD e a umidade do solo nas camadas superficiais é maior, propiciando condições que favoreçam o crescimento radicular, e consequentemente maior Mi e PT (BARRIOS et al, 2006). Os maiores valores de DS foram observados nas profundidades 0,0 -0,10 m; 0,10 -0,20 m e 0,20 -0,30 m (Tabela 2).…”