Inter-annual changes in the aggregate-size distribution and associated carbon of soil and their effects on the straw-derived carbon incorporation under long-term no-tillage

Abstract

Converting from conventional tillage to no-tillage influences the soil aggregate-size distribution and thus soil organic carbon (SOC) stabilization. However, the dynamics of soil aggregation and the straw-derived carbon(C) incorporation within aggregate fractions are not well understood. An experiment was established in 2004 to test the effects of two treatments, no-tillage with residue (NT) and conventional tillage without residue (CT), on the soil aggregate-size distribution and SOC stabilization in a continuous maize (Zea mays L.) cropping system located in the semiarid region of northern China. Soil samples were collected from the 0-10 cm layer in 2008, 2010 and 2015, and were separated into four aggregate-size classes (>2, 0.25-2, 0.053-0.25, and <0.053 mm) by wet-sieving. In each year, NT soil had a higher proportion of macroaggregates (i.e., >2 and 0.25-2 mm) and associated SOC concentration compared with CT. Additionally, to compare straw-derived C incorporation within NT and CT aggregate fractions, 13 C-labeled straw was incubated with intact NT and CT soils. After 90 days, the highest proportion of 13 C-labeled straw-derived C was observed in the >2 mm fraction, and this proportion was lower in NT than that in CT soil. Overall, we conclude that long-term continuous NT increased the proportion of macroaggregates and the C concentration within macroaggregates, and the physical protection provided by NT is beneficial for soil C sequestration in the continuous maize cropping system in semiarid regions of northern China.

Assessing the effects of different tillage systems on selected physical and chemical properties of a silty clay loam soil under different field conditions in the Czech Republic

“…The increase in saturated hydraulic conductivity on CT is expected to be short‐term with consecutive decreases through course of the vegetative season (Kool et al., 2019). Similar findings on significantly low saturated hydraulic conductivity values on consolidated CT soils have been previously reported (Park & Smucker, 2005; Yin et al., 2018). Findings here suggest that the high instabilities in saturated hydraulic conductivity on OT and CT were caused by negative effects of disruptions on the soil's natural porosity compared with RT and NT.…”

Effects of moisture content and tillage methods on creep properties of paddy soil

“…The elastic hysteresis time of NT paddy soil was prolonged; thus, the suitable tillage period of paddy soil could be prolonged by increasing soil organic matter. Relevant studies have shown that straw is rich in carbon content, and the decomposition of straw after returned to the field will form pores, thereby increasing soil porosity and activated carbon content [ 25 ].…”

“…At present, research on the influence of tillage methods on farmland soil mostly focuses on the physical properties of soil topsoil, such as the dynamic effect of farming systems on soil carbon and nitrogen in southern Brazil [ 24 ]. For instance, Yin et al [ 25 ] suggested that no tillage ridge cultivation could thicken the tillage layer, reduce soil disturbance, promote the formation of large aggregates, and improve soil structure and physical-chemical properties. Research on the influence of moisture content on soil mainly examines agricultural water, soil engineering and soil-machine dynamics, including studies on field soil compaction by machines [ 26 , 27 ] and on field water, soil conservation, and soil strength [ 28 , 29 ].…”

Role of cajuput waste compost against the physical quality of sandy soil

“…Organic materials can support the formation of more stable soil aggregate through organic polymer bonds with soil particles (Kogel-Knabner and Amelung, 2014). Soil aggregate stability highly depends on the soil texture, the content of clay fraction, the content of organic matter, the soil tillage, and the type of land use (Zhang et al, 2017; 1-month 4-month Zhao et al, 2017;Minasny and Mcbratney, 2018;Yin et al, 2018).…”