Carbon and Nitrogen Content of Soil Organic Matter and Microbial Biomass under Long-Term Crop Rotation and Tillage in Illinois, USA

Abstract

Abstract:Crop rotation and tillage alter soil organic matter (SOM) dynamics by influencing the soil environment and microbes carrying out C and N cycling. Our goal was to evaluate the effect of long-term crop rotation and tillage on the quantity of C and N stored in SOM and microbial biomass. Two experimental sites were used to evaluate four rotations-continuous corn (Zea mays L.) (CCC), corn-soybean (Glycine max [L.] Merr.) (CS), corn-soybean-wheat (Triticum aestivum L.) (CSW), and continuous soybean (SSS), each split into chisel tillage (CT) and no-till (NT) subplots. The CSW rotation increased soil organic carbon (SOC) content compared to SSS; SSS also reduced total nitrogen (TN) compared to other rotations. Levels of SOC and TN were 7% and 9% greater under NT than CT, respectively. Rotation did not affect microbial biomass C and N (MBC, MBN) while tillage reduced only MBN at 10-20 cm compared to NT, likely related to dispersion of N fertilizers throughout the soil. Despite the apparent lack of sensitivity of microbial biomass, changes in SOC and TN illustrate the effects of rotation and tillage on SOM dynamics. The inclusion of crops with high C: N residues and no-till use both support higher C and N content in the top 20 cm of the soil.

Effect of Tillage Systems on Spatial Variation in Soil Chemical Properties and Winter Wheat (Triticum aestivum L.) Performance in Small Fields

“…Our results showed that the increase in the N tot and C tot concentrations in NT compared with CT in the soil layer from 0 to 15 cm was very site-dependent and varied from about 2 to 20 % for N tot and from 4 to 12 % for C tot . Corresponding increases in other studies are mostly apparent on average values in NT and CT, varying between 7 to 40% after mostly longer terms [41,43,44]. Because the average annual input of above-ground crop residues in NT and CT soil were similar, the differences in the SOM content can be attributed to differences in the accumulation and decomposition of SOM under both tillage regimes [42].…”

Conservation Agricultural Practices Impact on Soil Organic Carbon, Soil Aggregation and Greenhouse Gas Emission in a Vertisol

“…Soil organic matter (SOM) is an important indicator of soil quality in tropical agricultural systems where fertility degraded/nutrient depleted and highly weathered soils are managed with little external input addition [5,6]. Various farm management practices, namely tillage, mulching, crop residue retention and the use of organic and synthetic fertilizers, have a significant impact on SOM dynamics [7][8][9][10]. Conservation agriculture (CA) based tillage practices such as no-tillage (NT) and minimum/reduced tillage (RT) significantly improve SOC as compared to conventional tillage practices [11][12][13][14][15].…”

“…Many researchers reported that CA practices/tillage methods significantly influence on water retention, pore size distribution, aggregate size distribution, aggregate stability [24][25][26][27], aggregate associated C and SOC [17,28,29]. Moreover, increasing crop residue addition can potentially improve higher SOC storage in CA systems [9,10,30,31]. However, in the areas where crop residue production is minimal, such as due to low soil fertility or soil constraints, residue retention may be insufficient to positively influence SOC storage [20,32].…”

Effects of Crop Rotation on Maize Soil Fertility in Alluvial Soil

“…The use of crop rotation systems is a beneficial measure to maintain or improve soil fertility due to enhancing crop residue and root system diversity, which affect soil biota activities, resulting in improved soil health and soil ecological interactions [9]. Many studies have reported that crop rotation is more capable of enhancing the total nitrogen (Ntot) and soil organic carbon (SOC) contents and improving soil porosity compared with an intensive crop rotation system [10,11]. Crop rotation can also reduce the number of insects and pathogens by disturbing their life cycle [12].…”