Functional diversity of soil microbial communities in response to tillage and crop residue retention in an eroded Loess soil

Abstract

This study reports the effects of a long-term tillage and crop residue experiment on the soil microbial ecology of a Loess soil located in Gansu Province, western China. Tillage and residue management treatments were imposed on a nine-year continuous rotation of maize (Zea mays L. cv Zhongdan No. 2), winter wheat (Triticum aestivum L. cv Xifeng No. 24) and soybean (Glycine max L. cv Fengshou No. 12). After nine years, there were significant effects on topsoil (0-10 cm) carbon, nitrogen, microbial activity, microbial composition and function. The retention of crop residues compared to residue removal significantly improved all measures of chemical and biological soil fertility. The values of average well color development (AWCD), a measure of the metabolic utilization of organic compounds, for the residue retention treatments were always higher than those with residue removal treatments, and the differences increased with increasing incubation time. Principal component analysis indicated that crop residue retention significantly altered topsoil microbial activity and community functional diversity. Our research clearly demonstrates that retention of crop residues significantly enhances soil microbial metabolic capacity, compared to no tillage, and can therefore contribute to sustainable agriculture on the Loess Plateau. Promotion of conservation agriculture has the potential to rehabilitate soil fertility and improve agricultural sustainability and food security on the region.

Weed dynamics and conservation agriculture principles: A review

“…In environments with sufficient moisture, residue could promote higher rates of seed decay. The increased micro-flora activity and biomass under residue (Doran, 1980;Govaerts et al, 2007;Yang et al, 2013) would seem to encourage higher rates of seed losses under residue due to decay (Derksen et al, 1996;Kennedy and Kremer, 1996;Chee-Sanford et al, 2006). This hypothesis has had little field testing, but one study found no difference in percent seed decay in exposed versus residue protected soil (Gallandt et al, 2004), indicating the effects may be more complicated and could involve nutrient status and seed coat characteristics (Davis, 2009).…”

Suppression of weeds and weed seeds in the soil by stubbles and no-tillage in an arid maize-winter wheat-common vetch rotation on the Loess Plateau of China

“…In 2011, common vetch replaced soybean in the crop sequence. Agronomic practices such as seeding and fertilization, were conducted following the recommendations of provincial standard (Yang et al, 2013). During the period 2001-2012, weed control was mainly by hand-cutting.…”

“…However, problems of weed control under these practices have restricted the application of these combined practices. Crop rotations that include winter wheat (Triticum aestivum L.) and some legume species are widely used in this rainfed area (i.e., Loess Plateau) to improve soil fertility as a result of enhanced content of soil organic matter, nitrogen and phosphorus (Liu et al, 2000;Wang et al, 2006;Yang et al, 2011), increased diversity and activity of soil microorganisms (Yang et al, 2013) and improved soil water content (Shen et al, 2009). This type of rotation is also important in livestock husbandry, for the provision of forage (Li et al, 2002;Ren, 2002;Zhao et al, 2011).…”

Yield, water productivity and economic return of dryland wheat in the Loess Plateau in response to conservation tillage practices

“…Beneficial effects on soil health, such as increased soil carbon reserve and soil microbial diversity, were consistently observed from previous research. Yang et al (2013 a , b ) found that NTS significantly enhanced soil microbial metabolic capacity, compared with no tillage, within the same field. Therefore, NTS has the potential to improve soil fertility and improve agricultural sustainability.…”