Time-course of soil microbial communities in different tillage and crop rotation systems

Abstract

The soil microbial communities involved in the biogeochemical cycles of plant nutrients are negatively affected by unfavorable agricultural practices. In three tillage systems (traditional tillage, TT; traditional tillage with residue incorporation, TTI; and conservation tillage, CT) with three crop rotations (cereal-cereal, CC ; legume-cereal, L-C; and cereal-legume, C-L) at three soil depths (0-5, 5-15, and 15-30 cm), the effects on the populations of bacteria, actinomycetes, and fungi over a period of six crop cycles (3 yr) were evaluated. The tillage system, crop rotation, and depth affected the concentration of microbes in the soil. Under TT/C-C (regional control), they decreased by 7.5%; in contrast, under CT/L-C and TTI/L-C, they increased by 144% and 76%, respectively. Regardless of the tillage system, rotation with legumes, especially when the legume was cultivated in the spring-summer cycle (C-L), caused significant increases in microbial populations. At the end of 3 yr, under CT and TTI the populations of actinomycetes increased, while the fungal population remained stable and the bacterial populations fluctuated in the different crop cycles. In all treatments, the concentration of microorganisms decreased with soil depth. Local practices represent a risk to the diversity of soil microbiota, and it is imperative that farmers adopt conservation practices to achieve sustainability.

Effects of Tillage and N Applications on the Cassava Rhizosphere Fungal Communities

“…Tillage is an important technical measure in agricultural production. Different tillage methods, that is, the intensity and mode of soil mechanical disturbance, can change the composition and particle size distribution of soil particles [1], thus affecting the physical properties of soil and indirectly affecting crop yield, soil nutrients, enzyme activities, and microbial community changes [2][3][4]. Nowadays, due to the shallow soil layer of traditional tillage plots, fertilizer utilization rate and yield are adversely affected year by year [5][6][7].…”