Tillage Methods Change Nitrogen Distribution and Enzyme Activities in Maize Rhizosphere and Non-Rhizosphere Chernozem in Jilin Province of China

Abstract

The tillage method in farming systems is essential to develop strategies to increase fertilizer uptake by plant roots and to avoid environmental pollution. The field study aimed to investigate the characteristics of nitrogen and enzyme activities in rhizosphere soil with different tillage methods. Four treatment plots applied with fertilizers were established: continuous rotary tillage (CR), plowing-rotary tillage (PR), continuous no-till (CN) and ploughing-no-till (PN). The total content of nitrogen in chernozem was high during early stages of plant growth, and then it decreased with the maize growth. In the rhizosphere soil, the total N accounted 1314.45, 1265.96, 1120.47, 1120.47, 1204.05 mg·kg−1 of CR, PR, CN, and PN, respectively, which were markedly greater than that of non-rhizosphere soil (1237.52, 1168.40, 984.51, 1106.49 mg·kg−1 of CR, PR, CN, and PN, respectively). At first growth stages, content of NH4+-N and NO3−-N in two soil regions was low, then increased gradually, which followed the order of CR < PR < PN < CN. The rhizosphere soil showed slightly higher concentration of NH4+-N and NO3−-N than non-rhizosphere. The soil enzymes were more active in the rhizosphere soil than that of non-rhizosphere during the whole maize growth stages. Due to minimal damage to the soil environment and optimal soil moisture and temperature, the urease and catalase activities were greatest in the rhizosphere for CN treatment. Therefore, CN was recommended to be used by farmers for the improvement of macronutrient availability and soil enzyme activities in the soil.

Inversion Tillage Combined with Organic Fertilizer Application Increased Maize Yield via Improving Soil Pore Structure and Enzymatic Activity in Haplic Chernozem

“…Previous studies have shown that SOC content and soil nutrient availability are reduced as soil depth increases, accompanied by changes in microbial biomass and activity [15]. Zhao [6] and Yang et al [7] reported that inversion tillage increases soil microbial biomass and improves soil enzymatic activities, which is consistent with our results. The soil pore structure and index of richness in the 15-35 cm layer were improved in this study (Tables 1 and 2; Figure 4), which suggests that inversion tillage can reduce soil physical restrictions and further homogenize the whole cultivated horizon, further increase soil nutrient availability, and enhance microbial biomass and activity [15].…”

“…Inversion tillage and organic fertilizer application showed positive effects on maize yields (Figure 3), contributing mainly to the improvements in soil nutrients and physical properties [5,6,29]. In our study, T35+M treatment resulted in a higher maize yield than other treatments, which can be explained by the fact that the 15-35 cm layers under T15 treatment dramatically limited deep root growth and development and thus restricted the utilization of soil nutrients by the crop in subsoil [33][34][35].…”

“…However, this could lead to large differences in soil quality between the topsoil and subsoil, which is not favorable for the retention of soil nutrients in the subsoil [1]. Inversion tillage, however, relocates topsoil rich in SOC and soil nutrients to the subsoil, and the translocation can contribute to the effect of SOC and nutrient sequestration [5,6,29].…”

“…Inversion tillage can break the plow pan, deepen the cultivated horizon, improve soil pore characteristics, and enhance soil infiltration and moisture retention capacity [3][4][5]. Some studies have shown that inversion tillage can increase the activities of urease and sucrase [6], enhance the growth and metabolic capacity of microorganisms [7] in the soil, and eventually activate soil nutrients and promote crop nutrient absorption by improving crop root growth [5]. Organic fertilizer is an important source of carbon (C), nitrogen (N), phosphorus (P), and microorganisms, providing energy and substrates for the growth of microorganisms.…”

Effects of Deep Vertical Rotary Tillage on Soil Water Use and Yield Formation of Forage Maize on Semiarid Land

“…Nevertheless, compounded by the predominance of small-scale farming, where tillage is often carried out using smaller machinery, forage maize productivity was often constrained by shallow tillage layers, compacted soil layers, and low nutrient uptake [13]. Prior research underscores the detrimental impact of traditional tillage practices on soil quality and crop development, exacerbating drought susceptibility and impeding yield stability and the growth of forage maize in northwest China [14,15].…”