Plow Tillage Research Articles

Effects of different tillage management on the growth and yield of maize (Zea mays l.)

Effects of different tillage management on the growth and yield of maize were studied from early June to September 2017. The experiment was set up with three tillage treatments: traditional shallow moldboard plow tillage with straw removal (MT), sub-soiling/ plow tillage /sub-soiling rotation with straw mulch (ST) and no-till/sub-soiling/no-till rotation with straw retention (NT). The soil compaction of different soil layers, plant height, chlorophyll content, above-ground biomass and yield were determined through the three tillage practices. Results showed that NT and ST treatments helped to reduce soil compaction, and had a positive effect on maize root growth and development, plant height and chlorophyll content compared to the MT treatment. The chlorophyll value in early growth period under NT and ST increased by 31.8 and 24.6%, respectively, and the plant height was increased by 20.2 and 15.9% compared with MT, respectively. The size order of soil compaction was MT > NT > ST, and the soil compaction value was the maximum at 20 cm under MT treatment, which was 1007 kPa. Meanwhile, NT and ST also increased the plant above-ground biomass and yield of maize. Compared to MT treatment, the dry weight of plants for the NT and ST treatments significantly increased by 24.3 and 15.7%, respectively, and the grain yield significantly increased by 11.9 and 14.9%, respectively (P < 0.05). NT and ST tillage treatments are effective measures to improve structure of soil, contribute to plant growth and development and thereby increase in yield. Bangladesh J. Bot. 52(2): 451-458, 2023 (June) Special

Effects of different tillage management on the growth and yield of maize (Zea mays l.)

Effects of different tillage management on the growth and yield of maize were studied from early June to September 2017. The experiment was set up with three tillage treatments: traditional shallow moldboard plow tillage with straw removal (MT), sub-soiling/ plow tillage /sub-soiling rotation with straw mulch (ST) and no-till/sub-soiling/no-till rotation with straw retention (NT). The soil compaction of different soil layers, plant height, chlorophyll content, above-ground biomass and yield were determined through the three tillage practices. Results showed that NT and ST treatments helped to reduce soil compaction, and had a positive effect on maize root growth and development, plant height and chlorophyll content compared to the MT treatment. The chlorophyll value in early growth period under NT and ST increased by 31.8 and 24.6%, respectively, and the plant height was increased by 20.2 and 15.9% compared with MT, respectively. The size order of soil compaction was MT > NT > ST, and the soil compaction value was the maximum at 20 cm under MT treatment, which was 1007 kPa. Meanwhile, NT and ST also increased the plant above-ground biomass and yield of maize. Compared to MT treatment, the dry weight of plants for the NT and ST treatments significantly increased by 24.3 and 15.7%, respectively, and the grain yield significantly increased by 11.9 and 14.9%, respectively (P < 0.05). NT and ST tillage treatments are effective measures to improve structure of soil, contribute to plant growth and development and thereby increase in yield. Bangladesh J. Bot. 52(2): 451-458, 2023 (June) Special

No-tillage and rye cover crop systems improve soil water retention by increasing soil organic carbon in Andosols under humid subtropical climate

No-tillage (NT) combined with a cover crop is a climate-smart agricultural practice that eliminates nearly all physical disturbance of the soil surface and increases soil aggregation and soil organic carbon (SOC); however, the response of SOC and soil water retention (SWR) to long-term NT and cover crops systems in the volcanic ash Andosol soil of Japan has not been well addressed. This study aimed to evaluate the effect of NT and moldboard plow (MP) tillage systems combined with rye (RY) and fallow (FA) cover crop treatments on SOC, active carbon (AC), water-stable aggregates, aggregate stability index, mean weight diameter (MWD), bulk density, aggregate-associated carbon, and SWR. NT significantly increased the > 4 and 2 mm aggregates, aggregate-associated C at the 0–2.5 and 2.5–5 cm depths, field capacity, and SWR between 0 and 15 cm. RY cover crops significantly increased aggregate-associated carbon at the 2.5–5 and 5–10 cm depths in both NT and MP and SWR at the 10–15 cm depth. NT combined with RY significantly increased SOC and AC in the surface layer and volumetric water content at all soil depths. Path analysis revealed that SOC and MWD were correlated with easily plant-available water (EPAW) and field capacity under the NT system and is the primary reason for the observed increase in SWR. Thus, the NT system increased plant residue, reduced soil evaporation, increased SOC content and SWR, and bonded soil microaggregates into macroaggregates better than the MP system. The use of an RY-based NT system is an effective climate-smart agriculture practice that reduces the drought effects brought on by climate change.

A comprehensive analysis of soil health indicators in a long‐term conservation tillage experiment

AbstractConservation tillage (CT) is a ploughless tillage with a reduced number of operations, and its positive effect on soil functions and health is widely known. Multivariate analyses are required to choose indicators that adequately characterize the changes in soil health. However, there is little research on the comprehensive analysis of the full spectrum of soil physical, chemical and biological properties. Therefore, we examined 21 soil parameters in a long‐term CT experiment conducted in Hungary. Four pairs of similarly sized CT and conventional ploughing tillage (PT) plots were set up in 2003 on Luvisols. The soil samples were collected after 17 years. The total organic carbon (TOC) increased significantly in the 0–15 cm layer at CT sites compared to those in PT, indicating a total increase of 5.22 t ha−1 TOC stock. In addition, the increasing biological activity and improved soil structure were the most important processes at the CT sites. Furthermore, more complex humic substances with higher molecular weights are characteristic of water‐extractable organic matter (WEOM) as a result of CT. The potentially available nitrogen, phosphorus and potassium were also measured with a relatively high response ratio. Slowly changing parameters, such as cation exchange capacity and base saturation, are important soil physical and chemical parameters, but are not good indicators of the impact of tillage practices. Based on principal component analysis, we suggest the use of water‐extractable organic C, amino‐nitrogen, water‐stable aggregates, available P and K and photometric analysis of WEOM to identify the soil improving processes.

Assessment of the effects of integrated rotation-tillage management on wheat productivity in the Loess Plateau region

The long-term use of conventional management practices coupled with the overapplication of synthetic fertilizers by smallholder family farms to meet food demand has negatively impacted the environment of farmland. Therefore, improved agronomic management practices are needed to enhance crop productivity. A 3-year (2016–2019) experiment was conducted to evaluate the effects of integrated rotation-tillage management [maize/soybean-wheat (MW/SW); chisel plow tillage (CPT), zero tillage (ZT), and plow tillage (PT)] on the farmland environment and wheat productivity in the Loess Plateau of China. The results indicated that SW and conservation tillage (CPT and ZT) increased soil nutrient levels and decreased soil pH and C/N values compared with conventional management practices (MW and PT); meanwhile, conservation tillage substantially increased soil moisture (SM, 3.56–16.06 %) compared with PT. Compared with MW and PT, SW and CPT increased aboveground biomass (0.26–4.45 % and 0.73–2.15 %, respectively) and nitrogen content (1.24–2.30 % and 0.26–2.73 %, respectively) during wheat development. Coincidentally, SW increased wheat actual yield (AY, 2.98 %) and maintained wheat theoretical yield (TY) and harvest index (HI) compared with MW; CPT increased wheat grain yield (AY, 6.72 %; TY, 3.28 %) and HI (2.26 %) compared with PT, while ZT caused significantly opposite results. CPT increased nitrogen fertilizer productivity (NfP, 3.28 %), nitrogen uptake efficiency (NupE, 1.19 %), and nitrogen use efficiency (NUE, 1.67 %) compared with PT regardless of crop rotations, while ZT significantly decreased NfP (9.69 %) and NupE (16.99 %) and increased NUE (8.18 %). Nevertheless, crop rotation did not substantially affect wheat nitrogen efficiency. Further correlation and partial least squares path modeling analysis revealed that elevated SM and nitrogen levels due to improved management practices had the potential to improve wheat productivity by regulating wheat growth characteristics. Overall, integrated SW-CPT management was more positive for improving farmland environment and enhancing wheat productivity in the Loess Plateau, which is suitable as a conservation strategy to adjust the cropping structure of smallholder family farms and promote sustainable agricultural development in arid and semiarid agricultural regions.

Effects of long-term tillage practices on the stability of soil aggregates and organic carbon in black soil farmland.

We examined the effects of different tillage practices on plough layer soil structure and organic carbon stabilization in black soil farmland with a long-term positioning platform. The wet-sieving method and infrared spectroscopy method were used to investigate the impacts of conventional tillage (CT), no-tillage (NT), sub-soiling tillage (ST), and moldboard plowing tillage (MP) on soil aggregates distribution and organic carbon characteristics in 0-40 cm soil layers. Compared to CT, both NT and ST treatments significantly increased the proportion of large macroaggregates (>2 mm) in the topsoil layer (0-20 cm)and that of small macroaggregates (0.25-2 mm) in the subsoil layer (20-40 cm) for NT, ST, and MP. NT, ST, and MP treatments resulted in higher mean weight dia-meter (MWD) and mean geometric diameter (GMD) of soil aggregates in both the topsoil and subsoil layers. NT treatment improved organic carbon contents in bulk soil and large macroaggregates in the topsoil layer, while ST and MP enhanced organic carbon contents in bulk soil and large macroaggregates in the subsoil layer. The contribution rate of small macroaggregates organic carbon content to the total was between 68.9% and 83.4%. Furthermore, the organic carbon chemical stabilization of soil body and aggregates increased in the topsoil and subsoil layers under NT treatment compared to others. The MWD had a positive correlation with the organic carbon content and chemical stability of soil body and small macroaggregates. These findings offered a theoretical basis for understanding the impacts of different tillage practices on the stability of soil aggregate and organic carbon in black soil region.

CHANGES IN PHYSICAL AND CHEMICAL PROPERTIES AND HUMUS CONTENT OF TYPICAL BLACK SOIL IN TREATMENT AND FERTILIZER SYSTEMS

The article presents the results of studies on the effectiveness of various systems of basic soil cultivation and fertilizer systems for growing winter wheat, and their impact on the physicochemical properties of typical black soil and organic matter content. The experiment included plough tillage, tillage with a 10-12 cm disc harrow, 'No-till' technology, and a mineral fertilizer system - source-saving minimized and intensive. The study was conducted in the agrocenosis of winter wheat. The results showed that shallow tillage with a disc harrow and resource-saving minimized mineral fertilizer increased the humus content in the 0-15 cm layer by 0.04% and in the 15-30 cm layer by 0.03% compared to inversion tillage. High rates of hydrolytic acidity (1.61-2.92 mol/m3/100 g of soil) were noted at all doses of mineral fertilizer when using inversion tillage. More optimized indicators of the sum of exchangeable bases of typical chernozem in a layer of 15-30 cm were noted during inversion tillage - 28.0 mol/m3/100 g of soil. The lowest value of the sum of exchangeable bases in the 15-30 cm layer was noted using the No-till technology - 27.6 mol/m3/100 g of soil. High rates of hydrolytic acidity (1.61-2.92 mol/m3/100 g of soil) were observed at all doses of mineral fertilizer using surface tillage. More optimized indicators of the sum of exchangeable alkaline of typical black soil in a layer of 15-30 cm were noted during shelf tillage - 28.0 mol/m3/100 g of soil. The lowest value of the sum of exchangeable alkalines in the soil layer of 15-30 cm according to the No-till technology was 27.6 mol/m3/100 g of soil.

Impact of Tillage and Straw Management on Soil Properties and Rice Yield in a Rice-Ratoon Rice System

The rice-ratoon system has long been considered an important economic, time-saving, and labor-saving planting method. Optimal tillage and straw management are beneficial to increasing the growth and yield of recycled rice. However, there is little research on the physical and chemical properties of soil under tillage and straw management, and its effects on the yield and fertilizer utilization of recycled rice. A field experiment was conducted to study the effects of four types of tillage and straw management on rice yield and soil properties in central China during 2020–2021. The types of management were no-till with residues retained (NT+S); plow tillage with residue retention (PT+S); no-till with residues removed (NT-S); and plow tillage with residue removed (PT-S). Compared with PT, yield decreased by 38.8% in NT, while straw returning effectively increased the yield of regenerated rice. NT+S increased the yield of main season rice by 37.0% and ratoon rice by 45.3%. Compared with non-returning straw, straw returning increased soil total porosity, soil organic carbon, and activity of β-glucosidase and urease, among which TP and SOC were increased by 8.8% and 27.8%, respectively. The results showed that returning straw to the field could significantly reduce the yield loss caused by no-tillage and improve the soil structure. No-tillage combined with returning straw to the field of regenerative rice is a green, light, and simplified cultivation mode worthy of further exploration.

Conservation tillage increases surface soil organic carbon stock by altering fungal communities and enzyme activity.

Fungal communities play a key role in the decomposition of crop residues and affect soil organic carbon (SOC) dynamics. Conservation tillage enhances SOC sequestration and mitigate global climate change. However, the impact of long-term tillage practices on fungal community diversity and its relation to SOC stock remains unclear. The objectives of this study were to evaluate the relationship between extracellular enzyme activities and fungal community diversity and SOC stock under different tillage practices. A field experiment was conducted with four tillage practices: (i) no-tillage with straw removal (NT0), (ii) no-tillage with straw retention (NTSR, conservation tillage), (iii) plough tillage with straw retention (PTSR), and (iv) rotary tillage with straw retention (RTSR). The results showed that the SOC stock in NTSR was higher than other treatments in the 0-10 cm soil layer. Compared to NT0, NTSR significantly increased soil β-glucosidase, xylosidase, cellobiohydrolase, and chitinase activities at 0-10 cm soil depth (P < 0.05). However, different tillage methods with straw returning had no significant effects on enzyme activity at 0-10 cm soil depth. The observed species and Chao1 index of the fungal communities under NTSR were 22.8% and 32.1% lower than under RTSR in the 0-10 cm soil layer, respectively. The composition, structure, and co-occurrence network of fungal communities differed across tillage practices. A partial least squares path model (PLS-PM) analysis indicated that C-related enzymes were the most influential factors associated with SOC stock. Soil physicochemical properties and fungal communities affected extracellular enzyme activities. Overall, conservation tillage can promote surface SOC stock, which was associated with increased enzyme activity.

The impacts of soil tillage combined with plastic film management practices on soil quality, carbon footprint, and peanut yield

Soil tillage and plastic film management practices are essential agricultural production strategies for improving crop yield. Furthermore, they can also play important roles in affecting soil quality, greenhouse gas (GHG) emissions, and carbon footprint (CF), and the overall impacts of tillage and plastic film management on these indicators and the potential links among them are rarely assessed. A 4-year-long field experiment was performed under the winter wheat–summer peanut rotation pattern to investigate how the tillage (plow tillage and rotary tillage) and plastic film management practices (plastic film mulching and no plastic film mulching) affected the summer peanut fields' soil quality (soil carbon (C) stock, enzyme activity, and nutrients concentration), soil GHG (N2O and CH4) emissions, CF components, and peanut yield. The present results showed that plow tillage management improved peanut yield and decreased seasonal cumulative soil N2O and CH4 emissions and CF relative to rotary tillage management. However, the seasonal cumulative emissions of soil N2O and CH4 under plastic film mulching were higher than those under no mulching. The application of plastic film mulching also increased soil TOC stock, soil enzymes (invertase, unease, and catalase) activities, and soil nutrients (microbial biomass C, microbial biomass nitrogen (N), ammonium N, and nitrate N) concentrations. The mulching-induced improvements in soil quality can promote an increase in crop productivity; thus, plastic film mulching showed increased peanut yield and decreased yield-scaled CF. In conclusion, plow tillage combined with plastic film mulching (PTM) treatment maintained higher peanut productivity and produced lower CF while generating suitable soil conditions and therefore may be a more high-yielding, eco-friendly, and sustainable development management strategy for summer peanut production.

Strategic tillage is a promising alternative to conventional and no-tillage: Evidence from a 12-year field trial in a double-cropped rice system

No-tillage (NT) has obvious advantages in reducing input and labour costs. However, some farmers have raised concerns about adapting continuous NT to manage farmland due to problems such as soil stratification and less yield. Therefore, occasionally targeted tillage (known as strategic tillage, ST) has been proposed as a flexible management measure. To evaluate the potential impact of a typical ST pattern on soil properties and yield, a 12-year positioning field trial was conducted with three tillage practices, including long-term no-tillage (NT), ploughing tillage (CT), and ST (3-year NT and 1-year CT), in an intensive double-cropped rice system in southern China. ST could alter soil physicochemical properties by reducing soil stratification and potentially increasing nutrient availability. ST alleviated the bulk density (BD) stratification caused by the continuous decrease in 0–5 cm BD and the continuous increase in 5–10 cm BD under NT, due to the periodic use of CT. Compared with NT and CT, ST increased the soil available K (AK) and available P (AP) concentrations without affecting the SOC or TN storage throughout the profile. However, ST lowered the soil acidification at the soil surface (0–5 cm) while increasing the risk of soil subsurface acidification. Relative to ST, yields with NT trended lower over time, and the yield gap between NT and ST increased as the experiment progressed. The multiyear average yield of ST was 0.31 t ha−1 higher than that of NT but lower than that of CT. ST had the potential to improve the low yield under NT. It may be related to the fact that the seed setting rate (the proportion of filled to total seeds) of ST was significantly higher than that of NT (p < 0.05). In conclusion, strategic tillage is a more sustainable tillage method than continuous no-tillage and ploughing tillage in double-cropped rice systems in southern China.

Eight-year tillage in black soil, effects on soil aggregates, and carbon and nitrogen stock

The effects of different tillage management practices on the soil aggregates, soil carbon stock (STCS), and soil nitrogen stock (STNS) are key issues in agricultural research. We conducted an 8-year field experiment to evaluate the effects of different tillage methods: stubble cleaning and ridging (CK), no-tillage with stubble retention (NT), plow tillage (PT), and width lines (WL) on soil aggregates, STCS, and STNS in the black soil corn continuous cropping area of Northeast China. Different tillage methods predominantly affected the soil aggregates in the 2–0.25 mm and 0.25–0.053 mm size classes. The PT methods increased the proportion of macroaggregates and improved the quality of the soil aggregates. PT methods significantly increased the soil organic carbon content at the 0–30 cm layer by changing the number of soil macroaggregates. The PT practices are better strategies for enhancing soil carbon sinks, and the WL method increased the total amount of N in the soil pool. Our results suggest that the PT and WL methods are the best strategies for improving the quality of soil aggregates and preventing/reducing depletion of soil C and N in a black soil area of Northeast China.

Soil Aggregates Stability Response to Summer Fallow Tillage in Rainfed Winter Wheat Fields on the Loess Plateau

Soil aggregates are one of the most important indicators of soil quality, which can be affected strongly by soil tillage. Little is known about the composition and stability of soil aggregates under summer fallow tillage in rainfed winter wheat fields on the Loess Plateau. Soil aggregates were assessed before sowing and after the harvest of winter wheat under three tillage treatments during summer fallow, including minimum tillage (FMT), subsoiling (FST) and plough tillage (FPT). The results showed that the 0.25–2 mm soil mechanical-stable aggregates (MSA) under the FPT treatment were significantly higher (25.5–42.1%) compared with the FMT treatment in the 0–40 cm soil layer before sowing. The FMT treatment significantly increased the 0.5–2 mm size WSA content (24.6–342.4%) compared with the FPT treatment in the 0–20 cm soil layer before sowing and after harvesting. Compared with the FMT treatment, the FPT treatment significantly increased the stability of the MSA in the 0–20 cm soil layer before sowing and the FST treatment significantly increased the stability of the MSA in the 0–50 cm soil layer after harvest. The FPT treatment significantly decreased the geometric mean diameter (4.2–9.3%) and the stability rate (73.6–252.6%) and increased the destruction rate (1.3–3.5%) and the unstable aggregate index of the WSA (0.8–2.3%) in the 0–20 cm soil layer before sowing, compared with the FMT treatment. In summary, the application of FPT and FST increased the stability of the MSA in the 0–20 cm soil layer; however, FMT improved the stability of the WSA in the 0–40 cm soil layer.

Effects of tillage on soil organic carbon and crop yield under straw return

No-tillage with straw mulch is an effective way to achieve soil sustainability. However, the specific redistributions of soil organic carbon composition, stocks, and crop yield remain unclear. The hypothesis that no-tillage had a minor effect on soil organic carbon stocks in 0–50 cm but decreased crop yield compared to plow-tillage under straw return was tested in this study. Soils properties from two decades of rice-wheat rotation field experiment were related to the yield of rice and wheat depending on tillage: 1) plow-tillage without straw return, 2) no-tillage with straw mulch, and 3) plow-tillage with straw return. No-tillage with straw mulch had the highest mean weight diameter of soil aggregates, the contents of macro-aggregates (>0.25 mm) organic carbon, particulate organic carbon (>53 µm), and soil organic carbon across tillage practices in 0–5 cm. However, it decreased the contents of macro-aggregates (>0.25 mm) organic carbon in 5–15 cm, the particulate organic carbon in 5–50 cm, and soil organic carbon in 5–30 cm compared to plow tillage with straw return due to less carbon input from roots and straw. Organic carbon stocks in micro-aggregates (<0.25 mm) and mineral-associated organic matter (<53 µm) did not vary between tillage practices. Hence the soil organic carbon stocks of plow tillage without straw return (48 Mg ha−1) were similar to that of no-tillage with straw mulch (51 Mg ha−1) but lower than that of plow tillage with straw return (57 Mg ha−1) in 0–50 cm. The mean annual yields of wheat and rice under no-tillage with straw mulch (14 t ha−1) were lower than that of plow tillage without straw return (15 t ha−1) and plow tillage with straw return (16 t ha−1). No-tillage-induced high soil bulk densities limited the rice yields. The yield losses of no-tillage with straw mulch were higher in rice than in wheat. The rice yield losses of no-tillage with straw mulch compared to plow tillage with straw return increased with experiment duration due to decreased available nitrogen in 7–14 cm and phosphorus contents in 0–14 cm over time. Conclusively, plow-tillage is more efficient for carbon sequestration and yield increase than no-tillage under straw return in rice-wheat farming by increasing carbon input in deep soils, soil available nutrients, and decreasing soil compactness.

Combining conservation tillage with nitrogen fertilization promotes maize straw decomposition by regulating soil microbial community and enzyme activities

Straw return can effectively improve farmland soil microenvironment and fertility. However, excessive straw in the topsoil adversely affects seed germination and crop growth. At present, the characteristics and key driving factors of straw decomposition in dry farmlands are unclear. Based on the interactions between tillage practices including zero tillage (ZT), chisel tillage (CT), and plow tillage (PT) and nitrogen (N) fertilization, i.e., low N (N1, 180 kg ha-1), normal N (N2, 240 kg ha-1), and high N (N3, 300 kg ha-1), quantitative polymerase chain reaction technology and an enzymatic detection kit were used to investigate the effects of key straw C-degrading enzyme activities and microbial abundance in soil on maize straw decomposition during the growth period of winter wheat in the winter wheat/summer maize double cropping system in a dry farmland of the Loess Plateau, China. Between 2018 and 2020, ZT and CT significantly increased winter wheat yield (by 10.94% and 12.79%, respectively) and straw decomposition velocity (by 20% and 26.67%, respectively), compared with PT. Compared to N1 and N3, N2 significantly increased wheat yield (by 4.65% and 5.31%, respectively) and straw decomposition velocity (by 26.33% and 13.21%, respectively). The partial least squares pathway modelling showed significant positive direct effects of soil moisture, NO3-, NH4+, total N, bacteria, and cellulase, laccase, and xylanase activities on straw decomposition, while soil pH, fungi, and Actinomycetes had significant negative direct effects. Overall, conservation tillage (ZT and CT) combined with N2 was beneficial for straw decomposition in the drylands of the Loess Plateau and improved straw resource utilization and basic soil fertility. The results of the study clarified the key drivers of straw decomposition in dry farmlands and provided new ideas for developing updated soil management practices and adaptive N application strategies to promote the resource utilization of straw and achieve the goals of carbon peaking and carbon neutrality.

Agricultural management strategies for balancing yield increase, carbon sequestration, and emission reduction after straw return for three major grain crops in China: A meta-analysis

Straw return can improve crop yield as well as soil organic carbon (SOC) but may raise the possibility of N2O and CH4 emissions. However, few studies have compared the effects of straw return on the yield, SOC, and N2O emissions of various crops. Which management strategies are the best for balancing yield, SOC, and emission reduction for various crops needs to be clarified. A meta-analysis containing 2269 datasets collected from 369 studies was conducted to investigate the influence of agricultural management strategies on yield increase, soil carbon sequestration, and emission reduction in various crops after the straw return. Analytical results indicated that, on average, straw return increased the yield of rice, wheat, and maize by 5.04%, 8.09%, and 8.71%, respectively. Straw return increased maize N2O emissions by 14.69% but did not significantly affect wheat N2O emissions. Interestingly, straw return reduced the rice N2O emissions by 11.43% but increased the CH4 emissions by 72.01%. The recommended nitrogen application amounts for balancing yield, SOC, and emission reduction varied among the three crops, while the recommended straw return amounts were more than 9000 kg/ha. The optimal tillage and straw return strategies for rice, wheat, and maize were plow tillage combined with incorporation, rotary tillage combined with incorporation, and no-tillage combined with mulching, respectively. A straw return duration of 5–10 years for rice and maize and ≤5 years for wheat was recommended. These findings provide optimal agricultural management strategies after straw return to balance the crop yield, SOC, and emission reduction for China's three major grain crops.

Microbial functional genes within soil aggregates drive organic carbon mineralization under contrasting tillage practices

AbstractSoil organic carbon (SOC) transformation is susceptible to tillage practices. Conservation tillage is known to optimize soil structure, improve microbial community diversity and increase SOC storage. However, how soil aggregate distribution and microbial community structure and function within aggregates affect SOC transformation under long‐term conservation tillage remains unclear. In this study, SOC mineralization dynamics were studied in situ and under laboratory conditions to examine the mechanisms by which C functional genes within soil aggregates of different sizes (i.e., mega‐, macro‐, and micro‐aggregates) influence SOC mineralization under long‐term tillage (i.e., zero, chisel, and plow tillage) in a dryland. The results indicated that in the winter wheat and summer maize rotation cropping system, SOC‐derived CO2‐C emissions were 143.99 and 133.29 g CO2‐C m−2 h−1 lower under chisel and zero tillage than that under plow tillage, respectively. Moreover, after 180 days of laboratory incubation, SOC mineralization in micro‐ and macro‐aggregates was 1.98 and 1.63 mg CO2‐C g−1 d−1 higher than that in mega‐aggregates, respectively. The aggregate‐associated differential modules of bacterial co‐occurring networks may be directly governed by bacterial community diversity and composition, which might play critical roles in driving SOC mineralization in response to different tillage intensities. Moreover, aggregate‐associated functional genes involved in labile and recalcitrant C compositions, which were determined by shotgun metagenomic sequencing, were associated with SOC mineralization and were significantly affected by the legacy effect of tillage intensity and aggregate size. Particularly, partial least squares path modeling revealed that genes involved in simple sugar metabolism exerted significantly positive effects on SOC mineralization, except for the effects of tillage intensity and aggregate size. Overall, this study showed that decreased abundances of labile C decomposition‐related functional genes within aggregates and community composition changes, as elucidated by the differences in bacterial network modules, under conservation tillage inhibit SOC mineralization. These findings may help in the development of adaptive soil tillage strategies for reducing carbon emissions in agroecosystems.

Do Cover Crops Increase Subsequent Crop Yield in Temperate Climates? A Meta-Analysis

Cover crops (CCs) are a promising strategy for maintaining and enhancing agroecosystem sustainability, yet CCs’ effects on the subsequent crop yield are highly variable. To quantitatively synthesize the effects of CCs on subsequent crop yield, a meta-analysis of 672 observations collected from 63 recent studies (2015 to 2021) in temperate climates was conducted. Legume CC species increased subsequent crop yield significantly more than grass (by 14%), nonlegume broadleaves (by 7%), and mixtures (by 2%). Incorporation of CC residue into soil increased crop yield by approx. 15% compared to leaving the CC residue on the soil surface. Relative to the no-CC control, the adoption of grass and legume CC species in non-organic vegetable cropping systems enhanced crop yield by 14% and 19%, respectively. Likewise, crop yield with legume CCs in coarse and medium textured soil, and under high precipitation conditions (&gt;700 mm), was significantly greater than the no-CC control by 18%, 4%, and 11%, respectively. Cover crops significantly increased vegetable crop yields and decreased the silage corn yield; however, grain corn, soybean, and winter wheat yield did not decrease with CC. Adoption of CC in no-tillage and plow tillage systems contributed to an increase in crop yield compared to the no-CC control. Our meta-analysis highlights that crop yield response to CC might become more robust when pedo-climatic conditions and agronomic factors are considered.

Influence of Crop Residue Management and Soil Tillage Method on Reducing the Carbon Footprint of Winter Wheat Production in the Salt-Affected Arable Land in the North China Plain

Salt-affected arable land is distributed widely in China, especially in the North China Plain. Crop residue management under appropriate tillage is critical to improving salt-affected soil organic carbon and reducing the carbon footprint. This study conducted four-year field experiments including two treatments (residue incorporated into soil with plough tillage (CT+); residue mulching with no-till (NT+)) in two sites (non-saline soil and salt-affected soil); the carbon footprint of wheat production was analyzed by life cycle assessment. The results showed that the carbon footprint of wheat production in the salt-affected soil was significantly larger than that in the non-saline soil, because the salt-affected soil exhibited higher N2O emission than the non-saline soil. CT+ has lower carbon footprint than the NT+, mainly due to the lower N2O emission and higher carbon sequestration in the CT+ compared to NT+. As for the salt-affected soil, the largest contributor of the carbon footprint per unit area was soil N2O emission, with a relative contribution of 40%; the largest contributor of the carbon footprint per unit yield was carbon sequestration, with a relative importance of 47–50%. Our results indicated that wheat production in salt-affected land has a high carbon footprint, while it can be decreased by incorporating crop residue into the soil under the plough tillage.

Shallow plough tillage with straw return increases rice yield by improving nutrient availability and physical properties of compacted subsurface soils

Shallow plough tillage with straw return increases rice yield by improving nutrient availability and physical properties of compacted subsurface soils