Tillage Modes Research Articles

Optimized Tillage Method Increased Rice Yield in Rice Ratooning System

Ratoon rice occupies an important position in rice production owing to its time-saving, labor-saving and low-pollution planting, and increased benefits. However, the impact of tillage management on the yield in rice ratooning system has not yet been reported. Thus, field experiments were carried out to investigate the impact of seven tillage methods on the yield of ratoon rice crop in Jingzhou City in 2021–2022. The managements included winter plowing + rotary 2 times (PTw + RT2) or 3 times (PTw + RT3), spring plowing + rotary 2 times (PTs + RT2) or 3 times (PTs + RT3), no plowing + rotary 2 times (P0 + RT2) or 3 times (P0 + RT3) and no tillage (NT). PTw + RT3 had the highest total rice yield. The experimental data were collected in 2021 and 2022. In terms of main season rice yield, the order of ranking was PTw > PTs ≈ NT ≈ P0, while for ratoon rice yield, the ranking was NT > PTw ≈ PTs > P0. Generally, the root function ranked as PTw > PTs > P0 > NT. The photosynthetic capacity of the main season rice always maximized in PTw, those of the ratoon rice all maximized in NT, and those of both the main season rice and ratoon rice always minimized in P0. In the three tillage modes (PTw, PTs, P0), an additional rotary tillage did not affect the growth or yield of rice. PTw + 3RT was the highest yielding tillage management, but it is still necessary to explore other PTw + 3RT methods and more economical tillage management to increase the yield of ratoon rice.

Effects of Straw Returning on Soil Aggregates and Its Organic Carbon and Nitrogen Retention under Different Mechanized Tillage Modes in Typical Hilly Regions of Southwest China

Tillage modes and straw returning influence soil aggregate stability and the distribution of organic carbon (C) and nitrogen (N) in aggregates of different particle sizes. In the typical hilly regions of southwest China, the predominant soil type is purple soil, characterized by heavy texture and high stickiness, with relatively lower soil fertility compared to other soil types. The improper use of fertilizers and field management practices further exacerbates soil compaction. However, abundant straw resources in the region provide an opportunity for comprehensive straw utilization. The effective utilization of straw resources is of significant importance for stabilizing agricultural ecological balance, improving resource utilization efficiency, and alleviating ecological pressure. Previously, most studies have focused on the impact of different mechanized tillage systems on the physical and chemical properties of soil in hilly areas, while research on the preservation of water-stable aggregates’ organic C and N content remains limited. In this study, the soil properties of fields under a winter pea–summer corn rotation for two years were studied with regards to the effects of straw returning on its water-stable aggregate distribution, macroaggregate content (R0.25), mean weight diameter (MWD), geometric mean diameter (GMD), and the organic C and N content in soil aggregates of different particle sizes and at different depths. The effects of five different tillage modes were assessed, namely rotary tillage with straw mixed retention (RTM), conventional tillage with straw burial retention (CTB), no-tillage with straw covered retention (NTC), subsoiling with straw covered retention (STC), and no-tillage without straw retention (NT). Based on the study results, under different tillage modes, straw returning effectively enhanced the soil organic carbon (SOC) and total nitrogen (TN) reserves at the plow layer (0–30 cm), SOC increased by 17.2% to 88%, and TN increased by 8.6% to 85.9%. At the same time, the content of 0.25–2 mm aggregates increased under the straw-return treatments under different tillage patterns. The NT treatment had the lowest R0.25 and MWD and GMD values for soil aggregates at different depths, which were significantly different (p < 0.05) from the other treatment modes. The correlation coefficients between SOC and soil aggregate stability indices ranged from 0.68 to 0.90, with most of them showing highly significant positive correlations (p < 0.01). In conclusion, straw returning under different tillage systems has improved soil aggregate stability and promoted soil structure stability. Specifically, the STC treatment has shown more pronounced effects on soil improvement in the upper soil layer of the hilly regions in southwest China, while the RTM treatment is beneficial for improving the lower soil layer. Therefore, the comprehensive experimental results indicate that the combination of STC and RTM treatments represents the most promising mechanized tillage and straw returning practices for the hilly regions in southwest China.

Optimization of the morphological, structural, and physicochemical properties of maize starch using straw returning and nitrogen fertilization in Northeast China

The combination of straw returning and nitrogen (N) fertilization is a popular tillage mode and essential strategy for achieving stable yield and high quality. However, the optimal combination strategy and the influence of tillage mode on the morphological, crystalline, and molecular structures of maize starch remain unclear. We conducted a long–term field experiment over 7 years in Northeast China using two tillage modes, rotary tillage with straw returning (RTS) and plow tillage with straw returning (PTS), and four N application rates. The relative crystallinity, 1045/1022 cm−1 value, and B2 and B3 chains of maize starch were higher under RTS than under PTS, resulting in increased stability of starch and improvements in gelatinization enthalpy and temperature. The surface of the starch granules induced by N fertilizer was smoother than that under the N0 (0 kg N ha−1) treatment. The proportion of amylose content, solubility, swelling power, and light transmittance increased under N2 (262 kg N ha−1) treatment, along with improvement in starch pasting properties. These results suggest that RTS combined with N2 treatment can regulate the morphological, structural, and physicochemical characteristics of maize starch, providing an essential reference for improving the quality of maize starch from an agronomic point of view.

Influence of tillage methods combined with mulching on soil physical properties and potato yield in dry farming area under different precipitation years.

We conducted a field experiment in the dry farming area in south Ningxia from 2018 to 2021, to explore the influence of tillage methods combined with mulching on soil bulk density, aggregate content, soil water storage and potato yield under different precipitation years. There were four tillage methods (15 cm depth ploughing, and 30 cm, 40 cm and 50 cm depth subsoiling) and three mulching measures (mulching with oat straw, plastic film and no mulching), with the ploughing depth of 15 cm without mulching as control. The results showed the combination of tillage and mulching effectively reduced soil bulk density in 0-60 cm layer after three years of farming compared with that prior to the experiment. Under the same tillage mode, the best effect was achieved in mulching with oat straw under different precipitation years. To be specific, the best effect in 20 cm and 40 cm soil layers was achieved in mulching with oat straw for 30 cm depth subsoiling, in 60 cm soil layer for 15 cm ploughing in wet year, and for 40 cm depth subsoiling in 20 cm, 40 cm and 60 cm soil layers in normal and dry years. In 0-20 cm soil layer, the content of >0.25 mm soil aggregate was the highest for 40 cm depth subsoiling with oat straw mul-ching in all the three years. In 20-40 cm soil layer, the content was the highest for 15 cm depth ploughing with oat straw mulching in wet year, and for 40 cm depth subsoiling with oat straw mulching in normal and dry years. In 40-60 cm soil layer, content was the highest for 15 cm depth ploughing with plastic film mulching, 30 cm depth subsoiling with plastic film mulching, and 30 cm depth subsoiling with oat straw mulching in wet, normal and dry years, which was increased by 18.8%, 27.0%, and 35.8%, respectively, compared with the control. In the key growth stage (from squaring to tuber expansion) of potatoes, soil water storage in 0-100 cm layer was optimal for 30 cm depth subsoiling with oat straw mulching in wet year and for 40 cm depth subsoiling with oat straw mulching in normal and dry years, with an increase of 19.4%, 19.5%, and 23.7%, respectively. Potato yield was the highest for 30 cm depth subsoiling with oat straw mulching in wet year and for 40 cm depth subsoiling in normal and dry years, with an increase of 84.6%, 81.7%, and 106.3%, respectively. The correlation analysis showed that improved soil physical properties played a significant role in increasing potato yield, with the most significant role of soil bulk density and soil water storage at the squaring stage. Potato yield was high at a tillage depth of 34.67-36.03 cm. We concluded that the combination of tillage method and mulching could effectively improve soil physical pro-perties and increase soil water storage in the growth stage of potatoes, thereby significantly increa-sing potato yield. Potato yield in dry farming area could be enhanced through 30 cm depth subsoiling with oat straw mulching in wet years, and 40 cm depth subsoiling with oat straw mulching in normal and dry years.

Monitoring of farmland dust during tillage and sowing operations and comparative analysis of cultivation modes in the suburban areas of Beijing

Agricultural machinery's tillage and sowing processes can generate much farmland dust, adversely affecting the surrounding environment. Clarifying the dust emissions from various agricultural machinery operations and selecting a reasonable cultivation mode is significant for reducing dust in the atmosphere and protecting the environment. However, a systematic exploration of the agricultural dust generated during agricultural machinery operations is needed. Here, we designed a dust monitoring system to monitor farmland dust (PM2.5, PM10, and TSP) and environmental parameters at different points. The system is applied to monitor the dust emission concentration caused by agricultural machinery. We found the concentration of PM2.5, PM10, and TSP from straw returning operations to be 2.06, 3.16, and 2.84 times higher than that of ploughing operations. The increase in cultivation speed will lead to an increase in dust concentration. In straw returning operations, compared with low-speed, the increase in PM2.5, PM10, and TSP concentration during medium-speed cultivation is 21.6%, 12.5%, and 16.8%, whereas high-speed cultivation is 68.2%, 38.9%, and 35.7%, respectively. Moreover, conservation tillage modes can significantly suppress dust emissions. We found that conservation tillage produced the lowest concentrations of PM2.5, PM10, and TSP during the tillage and sowing stages, which were 64.7%, 73.1%, and 72.1%, compared to traditional tillage. As the amount of straw coverage increases, the dust concentration decreases. The average PM2.5, PM10, and TSP concentration increment of NTS with LSMQ increased by 307.8%, 344.8%, and 346.8%. Our results demonstrate that adopting a conservation tillage and sowing model and increasing straw coverage can reduce dust emissions. The research results have specific guiding significance for reducing dust emissions during the spring and autumn cultivation. We anticipate evaluating further the contribution of small particulate matter generated during agricultural machinery operations to air pollution, and our research will provide a basis for future work.

Estimation of Soil Moisture Content of Farmlands Based on AEA Method of GPR

We used ground penetrating radar (GPR) to estimate the soil moisture content and its spatial distribution of farmland under different tillage modes in this paper. GPR data are collected on the farmlands with no-tillage (NT) and deep ploughing (DP), respectively. The average envelope amplitude (AEA) of GPR signal is used to estimate the soil moisture content which is constrained by time domain reflectometry (TDR) measurement. The findings of the field test indicate that the error of the moisture content obtained by AEA method is in a reasonable range. In the shallow layer of farmland, the AEA method of GPR for detecting the soil moisture content is feasible and different tillage modes can affect the change of soil moisture content.

Cleaner tillage and irrigation options for food-water-energy-carbon synergism in wheat−maize cropping systems

The conventional wheat−maize systems in the North China Plain are energy and water intensive with high carbon emissions. It is imperative to find cleaner production technologies for sustainable food-water-energy-carbon synergism. Here, a three-year field experiment was performed to explore the effects of two tillage modes and four irrigation regimes during wheat season on crop yield, economic profile, water use efficiency, energy utilization, and carbon footprint in typical wheat–maize cropping systems in the North China Plain. Pre-sowing irrigation resulted in the lowest crop yield and benefit profile. Pre-sowing + anthesis irrigation decreased economic benefit and water use efficiency with higher carbon footprint. Pre-sowing + jointing + anthesis irrigation led to the greatest energy consumption and greenhouse gas emissions. However, pre-sowing + jointing irrigation increased yield by 2.3–8.7%, economic benefit by 4.0–11.1%, water use efficiency by 7.4–10.9%, and net energy by 6.5–12.0% but reduced carbon footprint by 9.8–14.3% compared to pre-sowing + anthesis irrigation and pre-sowing + jointing + anthesis irrigation. The corresponding metrics in rotary tillage improved by 9.6%, 13.9%, 7.0%, and 14.2%, respectively, relative to subsoiling, whereas carbon footprint decreased by 12.4–17.2%. Besides, rotary tillage coupled with additional jointing irrigation obtained the highest value based on a Z-score method, which was recommended as a cleaner management practice to improve benefit return and water use efficiency with lower energy consumption and carbon footprint. This work provides valuable insights into food-water-energy-carbon nexus for ensuring food security and achieving environmental sustainability in the wheat−maize cropping systems.

Study of Physical and Mechanical Properties and Tillage Modes of Soil Under Modern Technological Principles

The availability of information about the physical and mechanical properties of the soil during the operation of tillage machines, including machines carrying out pre-sowing tillage, plays a key role in choosing the technological scheme and working bodies of the machine. The use of advanced tillage machines and technologies first of all requires studying the real situation of the corresponding physical and mechanical properties of the soil. From this point of view, the question raised has the same purpose. The studies were carried out on the territories of intensively agricultural regions and on samples taken from agricultural land. The results obtained during the experiment show that with an increase in the hardness of the soil from only 0.68 to 0.78 MPa, this cannot significantly affect the change in the resistivity of the working body. However, after this limit, an increase in the hardness of the soil significantly resists the working organ. In the course of the study, the physical and mechanical properties of the soil and the operating characteristics of the cutting body of the unit were also studied.

Efficient Utilization Mechanism of Soil Moisture and Nutrients with Ridge Film Furrow Seeding Technology of Sloping Farmlands in Semi-Arid and Rain-Fed Areas

How to improve the utilizations of water and nutrient is a research hotspot of sloping farmland in semi-arid and rain-fed areas. In this study, the spatial changes of soil moisture, nutrients, and roots under different tillage modes, as well as the efficient utilization mechanism of soil moisture and nutrients from rain-fed maize on three mulching treatments (no surface covering, ridge film and straw mulch and ridge film mulch) and two slope treatments (5° slope and 10° slope) of sloping farmlands were studied at the Nationally Agricultural Environment Fuxin Observation and Experiment Station in China through a micro-zone simulation and a long-term positioning experiment. The results indicated that ridge film mulch and furrow seeding significantly improve the water use efficiency and partial factor productivity of the plants in sloping farmlands, with the highest increases being 51.33% and 45.05%. By analyzing the coordinated relationship between water, nutrients, and roots, it was found that ridge film furrow seeding technology can significantly affect the spatial distribution of water, nutrients, and roots in different soil layers, and improves the effective coefficient of soil water and nutrients. The effective coefficient of ridge film and straw treatment was 2.53, while the average value of the effective coefficient of ridge film treatment was 1.39. Further analysis found that the degree of consistency between the root system, water, and nutrient barycenter was highly correlated with the effective coefficients of water and nutrients. Visual radar map analysis revealed that root development limits the improvement availability of the efficient use of water and nutrients in the soil. Promoting root development indicators and root spatial distribution through ridge film coverage was an effective way to improve the efficient use of maize water and nutrients. The ridge film mulching promoted the root development index and root spatial distribution, thus improving the efficient use of water and nutrients in maize. Overall, the ranking of the regulation effect was as follows: ridge film and straw mulch > ridge film mulch > no mulch, and 5° slope > 10° slope. This research provided a theoretical basis for the enhancement of use efficiency in water and nutrients in sloping farmlands.

Analysis on Change in Soil Organic Carbon Content of Farmland in Yangtze River Economic Belt Under Different Fertilizing Measures

The literature from a long-term fertilization experiment in the Yangtze River Economic Belt from January 1992 to May 2022 was collected, and the data of farmland soil organic carbon were extracted and integrated. Using the normalization treatment and the analysis method of relative annual variation, the overall change in soil organic carbon content in farmland in the Yangtze River Economic Belt under different long-term fertilization measures was studied, and the change differences of soil organic carbon content under three tillage modes were compared so as to judge and analyze the influence of the duration of the experiment on soil organic carbon dynamics. The results showed that under different long-term fertilization measures, the organic carbon content of farmland soil in the Yangtze River Economic Belt in China showed an overall upward trend. The NP, NPK, O, and NPKO treatments all increased the organic carbon content of agricultural soils, with that of the NPKO treatment being the largest. The sole application of inorganic nitrogen fertilizer reduced the organic carbon content of the soil. The rates of change in soil organic carbon content were 0.22 g·(kg·a)-1, 0.24 g·(kg·a)-1, and 0.16 g·(kg·a)-1for dryland, paddy, and water-dry rotation farmland, respectively. Additionally, the relatively rapid increase effect of organic carbon brought by the O and NPKO treatments could last for no more than 28 years in dryland soil but could still last for more than 28 years in paddy field and paddy-upland rotation soil. There was some variation in the rate of change of soil organic carbon content between soil types. The average rate of change of organic carbon was 0.25 g·(kg·a)-1for red soils, 0.14 g·(kg·a)-1 for brown soils, 0.19 g·(kg·a)-1 for tidal soils, and 0.15 g·(kg·a)-1 for rice soils. The trend of NPKO>O>NPK>NPK>NP>N was basically maintained for the rate of change in soil organic carbon content. The NPKO treatments were all significantly higher than the chemical fertilizer (N, NP, and NPK) treatments alone. The N treatment showed a reduction in organic carbon content in both red soil and rice soils. Considering the carbon fixation of farmland soil, the combined application of organic and inorganic fertilizers is a more suitable fertilization method in this area.

Improving wheat seedling quality through deep ploughing and soil compaction at sowing in lime concretion black soil.

The straw incorporation in lime concretion black soil compromises the emergence and quality of winter wheat seedlings in Huaibei Plain, China, lowering the potential of wheat productivity. To overcome the disadvantage, a two-year field experiment was conducted in 2017-18 and 2018-19 to investigate the effects of different tillage modes on seedling emergence and subsequent seedling growth, and final grain yield (GY) in winter wheat. The modes are rotary tillage with compaction after sowing (RCT), rotary tillage after deep ploughing (PT) and rotary tillage after deep ploughing with compaction after sowing (PCT), with the traditional rotary tillage (RT) method as the control. Compared to RT, greater soil moisture content (SMC) at the seedling stage was observed in deep ploughing or compaction treatment, and the highest SMC was achieved in PCT; the time of reaching the maximum number of seedlings was 1 d sooner in RCT or PT, and 3 d in PCT; the seedling number in RCT, PT and PCT was significantly increased by 32.6%, 34.5% and 61.5% respectively. The population size, shoot and root growth of winter wheat in ploughing mode was significantly enhanced than that of rotary treatment at the over-wintering stage; compared to no compaction after sowing, plant growth in compaction treatments was significantly promoted with greater plant population size and height of seedlings. At harvest, GY in RCT, PT and PCT was significantly improved by 5.87%, 10.8% and 16.4%, respectively, compared to RT and the highest GY was achieved in PCT by up to 8, 350.1 kg ha-1 due to the increased spike number. In conclusion, the seedling quality in the straw incorporation practice was improved through rotary after deep ploughing and compaction after sowing for lime concretion black soil in Huaibei Plain, China or a similar soil type.

Effects of tillage patterns and stover mulching on N2O production, nitrogen cycling genes and microbial dynamics in black soil

Stover-covered no-tillage (NT) is of great significance to the rational utilization of stover resources and improvement of cultivated land quality, and also has a profound impact on ensuring groundwater, food and ecosystem security. However, the effects of tillage patterns and stover mulching on soil nitrogen turnover remain elusive. Based on the long-term conservation tillage field experiment in the mollisol area of Northeast China since 2007, the shotgun metagenomic sequencing of soils and microcosm incubation were combined with physical and chemical analyses, alkyne inhibition analysis to elucidate the regulatory mechanisms of NT and stover mulching on the farmland soil nitrogen emissions and microbial nitrogen cycling genes. Compared with conventional tillage (CT), NT stover mulching significantly reduced the emission of N2O instead of CO2, especially when 33% mulching was adopted, and correspondingly the nitrate nitrogen of NT33 was higher than that of other mulching amounts. The stover mulching was associated with higher total nitrogen, soil organic carbon and pH. The abundance of AOB (ammonia-oxidizing bacteria)-amoA (ammonia monooxygenase subunit A) was substantially increased by stover mulching, while the abundance of denitrification genes was reduced in most cases. Under alkyne inhibition, the tillage mode, treatment time, gas condition and interactions between them noticeably influenced the N2O emission and nitrogen transformation. In CT, NT0 (no mulching) and NT100 (full mulching), the relative contribution of AOB to N2O production was markedly higher than that of ammonia oxidizing archaea. Different tillage modes were associated with distinct microbial community composition, albeit NT100 was closer to CT than to NT0. Compared with CT, the co-occurrence network of microbial communities was more complex in NT0 and NT100. Our findings suggest that maintaining a low-quantity stover mulching could regulate soil nitrogen turnover toward proficiently enhancing soil health and regenerative agriculture, and coping with global climate change.

Effects of Agricultural Machinery Operations on PM2.5, PM10 and TSP in Farmland under Different Tillage Patterns

Agricultural machinery can improve agricultural productivity and promote agricultural scale operation. However, machinery operations lead to increased dust in farmland and affect the atmospheric environment; thus, they have been increasingly emphasized. In this study, the effects of agricultural machinery operations in wheat cultivation were investigated regarding the emissions of three kinds of particulate matters, namely fine particulate matter (PM2.5), inhalable particulate matter (PM10) and total suspended particulate (TSP), from farmland in Beijing. The results showed that the total dust emission from the traditional tillage mode, including straw crushing, rotary tilling and sowing, was 3.990 g per hectare, which was larger than that of the conservation tillage mode including only no-tillage sowing (0.407 g per hectare). The total dust emission for one hectare of farmland under the two modes was 3.415 g, 0.497 g, 0.407 g and 0.078 g for straw shredding, rotary tillage, no-tillage sowing and conventional sowing, respectively. The values of PM2.5/PM10 and PM2.5/TSP decreased in each tillage section after each agricultural machinery operation, while the values of PM10/TSP were basically unchanged, indicating that particulate matter emissions from farmland due to agricultural machinery operations are mainly PM10 and TSP. The dust concentration generated by agricultural machinery increased with an increase in the speed of the machinery operation, provided that the quality of the operation was guaranteed. This study provides guidance for reducing dust emissions from mechanized operations, improving air quality and decreasing health hazards to operators of agricultural machinery.

Responses of anaerobic ammonia-oxidizing bacteria and methane-oxidizing archaea communities from different tillage modes in paddy fields

Responses of anaerobic ammonia-oxidizing bacteria and methane-oxidizing archaea communities from different tillage modes in paddy fields

Differentiation in Nitrogen Transformations and Crop Yield as Affected by Tillage Modes in a Fluvo-Aquic Soil

Nitrogen is a vital element for soil fertility and crop productivity. The transformation of nitrogen is directly affected by tillage practices for the disturbing soil. The characteristics of different nitrogen forms under different tillage modes are still unclear. A 3-year cycle tillage experiment was carried out to assess the combination of rotary tillage (RT), deep tillage (DT), and shallow rotary tillage (SRT) on nitrogen transformation and distribution, wheat yield and nitrogen balance in fluvo-aquic soil from Huang-Huai-Hai Plain in China. The results showed the rotation tillage cycle with deep tillage in the first year increased the total nitrogen (TN), and the main nitrogen form content in 0-30 cm compared with continued rotary tillage (RT-RT-RT). Moreover, the nitrate (NO3--N) and ammonium nitrogen (NH4+-N) content were improved in 20-40 cm by deep tillage practice with the highest value as 39.88 mg kg-1 under DT-SRT-RT. The time, tillage, and depth significantly affected the different nitrogen forms, but there was no effect on dissolved organic carbon (DON) and soil microbial biomass nitrogen (SMBN) by the interaction of time and tillage. Moreover, compared with RT-RT-RT, the rotation tillage promoted the spike number and kernels per spike of wheat, further increasing the wheat yield and nitrogen partial productivity, and with a better effect under DT-SRT-RT. The NO3--N and NH4+-N trended closer and positively correlated with wheat yield in 0-40 cm in 2019. The rotation tillage with deep tillage improved the different forms of nitrogen in 0-30 cm, wheat yield, and nitrogen partial productivity, and decreased the apparent nitrogen loss. It was suggested as the efficiency tillage practice to improve nitrogen use efficiency and crop yield in this area.

A seven‐year study on the effects of four tillage modes on soil physicochemical properties, microbial biomass, enzymatic activities, and grain yield in a rice–ratoon rice cropping system

AbstractRatoon rice is resource efficient to produce economically sound and environmentally sustainable rice production. However, there is no more information on the relative impact of soil tillage practices on soil physical and chemical properties, microbial biomass, and enzymatic activity, and grain yield in a rice–ratoon rice cropping system remains to be tested. Systematic study of soil under ratooning rice model is a problem to be solved in the development of ratooning rice model. This study primarily investigated the long‐term (from 2014 to 2020) changes in soil bulk density (BD), soil organic carbon (SOC) concentration, total nitrogen (TN) concentration, microbial biomass, β‐glucosidase activity (BG), urease activity (UR), and yield under four treatments: no‐tillage (NT), no plowing tillage + rotatory tillage (RT), plowing tillage in winter + rotatory tillage (PTW), and plowing tillage in spring + rotatory tillage (PTS). NT increased BD by 9.65%–12.97%, and RT increased the 20–40 cm soil layer BD by 8.80% in 2020, compared with the baseline initial value (in 2014). Plowing tillage (PT) time had no significant effect on BD. All tillage methods decreased the SOC concentration in the 0–20 cm soil layer, and only RT increased the TN concentration. PT was the only treatment that increased the SOC and TN concentrations in the 20–40 cm soil layer. Both the main‐season rice yield and the ratoon season rice yield ranked PTW > PTS > NT > RT, in which the main‐season rice yield increased by 28.15% and the ratoon season rice yield increased by 25.19% in PTW. Overall, the PTW treatment had the highest microbial biomass, enzyme activity, and grain yield compared with the other tillage methods. In conclusion, plowing tillage in winter + rotatory tillage is a more suitable tillage method under the mode of ratooning rice.

Use of multifractal parameters to determine soil particle size distribution and erodibility of a physical soil crust in the Loess Plateau, China

Understanding the knowledge of multifractal analysis on particle size distribution (PSD) of soil physical crusts is indispensable for progressing soil surface erosion mode. In this study, hoeing tillage (20 cm long × 15 cm wide × 5 cm deep) were conducted to simulate classic tillage mode in Yangling, China to obtain physical crusts under artificial rainfall (60 mm h−1 intensity with three durations (5, 15, and 30 min)). We defined crusts formed in ridges as structural crust (Cst), formed by infiltration of runoff in hoes as sediment-containing depositional crust (Cscd), and formed by the extraction of runoff as sediment-free depositional crust (Csfd). Soil stratification methods were used to explore physical crust particle sorting. Results represented that the sand content of Cst, Cscd, and Csfd decreased, whereas clay and silt contents increased after rainfall compared to undisturbed soil. There was no significant difference between Cscd and Csfd under short rainfall duration. Three crust types became gradually concentrated in areas with higher density with increasing rainfall duration according to six common parameters in the generalised dimension spectrum (D0, D1, D2, D1/D0, Dv(D-10–D0), and Ds(D0–D10)). Multifractal singularity spectrum (α0, Av, Fv) showed that PSD was most symmetrical in Csfd, followed by Cscd and Cst. Erodibility index KEPIC was largest for Cst, followed by Csfd then Cscd. The relationship between KEPIC and multifractal parameters were significant. Spatial difference caused by tillage activities and rainfall events determine the heterogeneous formation mode, particle size distribution and erodibility of physical crust.

Motor Torque Distribution Strategy for Different Tillage Modes of Agricultural Electric Tractors

Aiming at the existing single-motor agricultural tractors, which often have a mismatch between power and working conditions and a poor operation effect under different tillage modes, this paper designs a torque allocation strategy for agricultural electric tractors under different tillage modes. Firstly, the torque is divided into basic and compensating, and a calculation model is established. Then, the Particle Swarm Optimization algorithm is used to find the optimal demand torque position, and fuzzy control rules allocate the motor torque in combination with the battery SOC. Finally, the strategy’s effectiveness in different tillage modes is verified by MATLAB/Simulink simulation and bench test. The test results show that the strategy can distribute the motor torque stably according to the load torque change and pedal opening under three PTO transitions and the plowing and rotary tillage modes. The main and speed control motors respond in about 3 s with good real-time performance. The drive wheel torque can reach 1600 N·m during plowing and rotating operation. The PTO torque can reach 60 N·m during the rotating process. The maximum torque of the output shaft can reach 150 N·m with good plowing performance. During all operations, the SOC of the battery shows a steady linear decrease, and the battery discharge has stability.

Effect of Tillage and Residue-Returning Mode on Soil Carbon Mineralizability and Accumulation in a Wheat–Maize System

Conservation tillage has been widely adopted to improve soil organic carbon (SOC) accumulation. To assess the effects of different tillage and residue-returning modes on SOC mineralizability and accumulation, a field experiment was conducted in 2015, including two tillage modes, i.e., no-tillage (NT) and rotary-tillage (RT), as well as three straw-returning modes, i.e., no straw returning (N0), wheat straw returning (WR), and wheat–maize straw retuning (WM). Wheat–maize root, maize straw, and wheat straw were added to soil samples during laboratory incubation. The results showed that NT significantly increased SOC concentration by 26.75% at a depth of 0–10 cm (p < 0.01). Although NT significantly decreased SOC mineralizability at soil depths of 0–10 cm and 10–20 cm (p < 0.05), the residue did not significantly affect SOC mineralizability in the 0–20 cm layer. The potentially mineralized C (Cp) and organic labile C fraction (C1) increased with the increase of residue amount. A significant correlation (R2 = 0.662) was observed between C1 and SOC concentration. Notably, SOC concentration and mineralizability without straw returning were insignificant between N0 and WR in the 0–10 cm and 0–20 cm layers, respectively. This suggests that NT with WR is a promising strategy to increase SOC concentration and decrease mineralizability.

Research on the Effect of Conservation Tillage Mode on the Suppression of Near-Surface Dust in Farmland

In order to explore the beneficial effects of conservation tillage (straw burial, stubble + straw mulching, straw mulching) compared with traditional tillage on suppressing farmland dust and the law on farmland wind erosion, PM2.5 and PM10, in this study, according to the distribution characteristics of farmland dust particles “from large to small” and “from bottom to top”, the self-designed dust collector and farmland dust online monitoring system were used to analyze the amount of wind and dust, PM2.5 and PM10, near the surface of farmland. A comparative study on the dust emission of farmland from conservation tillage and traditional tillage is conducted in two dimensions. The mobile wind tunnels are used to simulate and verify the release of PM2.5 and PM10 near the surface of farmland. Among them, the monitoring of farmland wind erosion shows that compared with traditional farming, the wind erosion of straw burial, stubble + straw mulching, and straw mulching decreased by 29.37%, 40.73%, and 36.61%, respectively, and 90~250 μm large-size sand particles are reduced by 37.2%, 74.7%, and 31.6%, respectively. The monitoring results of PM2.5 and PM10 near the surface of the farmland showed that the stubble + straw mulching model is compared with the traditional farming farmland. The reductions were 42.5% and 40.8%, significantly higher than the straw burial and straw mulching modes. The multiple linear regression analysis of the monitoring data showed that the PM2.5 and PM10 release concentrations near the surface of farmland had the highest correlation with wind speed, followed by soil moisture and temperature. Wind tunnel test verification shows that the following three protective tillage modes: straw burial, straw mulching, and stubble + straw mulching, have apparent inhibitory effects on PM2.5 and PM10 released on farmland compared with traditional tillage modes. In 1~8 m/s interval, the release concentration of PM2.5 in the modes of straw burial, stubble + straw mulching, and straw mulching decreased by 15.34~41.17%, 32.05~48.56%, and 28.85~42.40%, and the PM10 release concentration decreased by 19.44~36.47%, 35.90~52.00%, and 25.83~50.63%, respectively, which are consistent with the monitoring results of PM2.5 and PM10 near the surface of farmland. The research results show that the beneficial effects of each model on farmland dust suppression are stubble + straw mulching > straw mulching > straw burial. The study is intended to provide theoretical support for promoting conservation tillage and the return of high-quality straw mulch to the field in Beijing.