Assessment of soil quality under different tillage practices during wheat cultivation: soil enzymes and microbial biomass

Abstract

Microbial processes, particularly enzyme activities, play crucial functional roles in soil ecology, hence serving as sensitive indicators of soil quality. We assessed the temporal dynamics of microbial biomass and selected soil enzymes (β-d-glucosidase, cellobiohydrolase, polyphenol oxidase, urease, glycineaminopeptidase and alkaline phosphatase) during wheat cultivation, under four different tillage practices in the rice-wheat system. The four practices involved conventional tilling of soil before cultivating each crop (CTR-CTW); no tilling before cultivating rice but conventional tillage before wheat (NTR-CTW); conventional tilling before cultivating rice but no tilling before wheat (CTR-NTW) and no tilling before cultivation of each crop (NTR-NTW). Microbial biomass and activities of hydrolytic enzymes increased under NTR-NTW followed by CTR-NTW and NTR-CTW with respect to the conventional practice CTR-CTW, thus reflecting improvement in microbial activities with reduced tillage frequency. Enzyme activities generally depended on soil moisture and temperature, but nature of relationships varied among different practices. Nutrient demand appeared to be the strongest driver of alkaline phosphatase and urease, and soil temperature for glycine-aminopeptidase. Under CTR-CTW, activities of most of the extracellular enzymes were related with β-d-glucosidase or urease, but such relations altered under rest of the practices. The study showed that extracellular soil enzymes respond sensitively to tillage practices as well as environmental variables, particularly soil temperature and moisture and hence can serve as a sensitive indicator of changes in soil processes. Considering improvement in microbial biomass and enzymatic activities as indicators of better soil quality, adoption of no tillage apparently improved soil quality. Still, more number of field studies are required under tillage managements to explore the relationships between different enzyme activities and environmental factors.

Assessing microbial activities in metal contaminated agricultural volcanic soils – An integrative approach

“…In addition, the efficient soil co-extraction of RNA and DNA makes possible to calculate the RNA:DNA ratio, which can be an important indicator of the metabolic status of soil microbial communities. These microbial activities can be used as indicators of soil quality to monitor soil metal contamination (Niemeyer et al, 2012;Xian et al, 2015) and agricultural soil management practices (Bowles et al, 2014;Pandey et al, 2015). Despite the numerous field studies demonstrating the adverse effects of metal contamination on soil microbial activities (Kuperman and Carreiro, 1997;Antunes et al, 2011;Niemeyer et al, 2012), there is a lack of knowledge regarding the soil microbial responses to chronic metal contamination when soils are naturally enriched with trace metals and have been extensively used for agricultural purposes, such as in agricultural volcanic soils (Andosols).…”

Soil characteristic changes and quality evaluation of degraded desert steppe in arid windy sandy areas

“…This is because the upper soil contained various kinds of litter spoilage rich in organic matter, and had a loose and porous structure that provided relatively good living conditions for microorganisms. Moreover, the temperature of the upper soil was higher than that of the lower soil, making the degradation of plant litter greater and the soil enzyme activity higher ( van Bruggen & Semenov, 2000 ), which were all helpful for the growth and reproduction of various microorganisms ( Pandey, Agrawal & Bohra, 2015 ). In the severely degraded grassland, the vegetation was sparse, the surface soil was exposed to the air, soil desertification was serious, and the temperature of the surface soil changed greatly.…”

“…It characterizes the biological activity of soil and participates in biochemical functions and nutrient cycling ( Maurya et al, 2020 ). It can quickly respond to microenvironmental changes in the soil ( Pandey, Agrawal & Bohra, 2015 ), is highly sensitive to external interference, and is easy to measure. Soil enzyme activity showed a downward trend with grassland degradation because soil enzyme activity is closely related to soil organic matter content and soil physical and chemical properties, and the soil nutrient poorness during the process of grassland degradation caused the decline of enzyme activity.…”

“…Nitrogen is a major nutrient for vegetation growth and an important indicator for evaluating soil quality ( Pham, Nguyen & Kappas, 2018 ). Soil microorganisms and enzyme activities are early indicators for assessing the degree of soil degradation, and are sensitive to soil disturbances related to nutrient cycling and organic matter dynamics ( Guo et al, 2018 ; Nosrati & Collins, 2019 ; Pandey, Agrawal & Bohra, 2015 ). There are many methods used for evaluating soil quality: the comprehensive index method ( Zhang et al, 2017 ), fuzzy comprehensive evaluation method ( Wang, Yang & Shan, 2001 ), principal component analysis method ( Juhos et al, 2019 ), gray correlation method ( Li, Tang & Li, 2004 ), and the soil quality index (SQI) ( Zhou et al, 2020 ).…”

Effect of green garlic/cucumber crop rotation for 3 years on the dynamics of soil properties and cucumber yield in Chinese anthrosol

“…In plant–soil interactions, the soil enzyme activity is a very important tool that helps to determine the overall soil microbial count and soil quality; thus activities of soil enzymes can be utilized as sensitive indicators of changes in soil biological activity and fertility in response to different soil management practices . Invertase activity reflects the fertility level and degree of maturation of the matrix, which play important roles in increasing soil nutrient levels.…”