Subsoil tillage enhances wheat productivity,soil organic carbon and available nutrient status in dryland fields

Tillage practices during the fallow period benefit water storage and yield in dryland wheat crops.However,there is currently no clarity on the responses of soil organic carbon(SOC),total nitrogen(TN),and available nutrients to tillage practices within the growing season.This study evaluated the effects of three tillage practices(NT,no tillage;SS,subsoil tillage;DT,deep tillage)over five years on soil physicochemical properties.Soil samples at harvest stage from the fifth year were analyzed to determine the soil aggregate and aggregate-associated C and N fractions.The results indicated that SS and DT improved grain yield,straw biomass and straw carbon return of wheat compared with NT.In contrast to DT and NT,SS favored SOC and TN concentrations and stocks by increasing the soil organic carbon sequestration rate(SOCSR)and soil nitrogen sequestration rate(TNSR)in the 0-40 cm layer.Higher SOC levels under SS and NT were associated with greater aggregate-associated C fractions,while TN was positively associated with soluble organic nitrogen(SON).Compared with DT,the NT and SS treatments improved soil available nutrients in the 0-20 cm layer.These findings suggest that SS is an excellent practice for increasing soil carbon,nitrogen and nutrient availability in dryland wheat fields in North China.

Optimized tillage methods increase mechanically transplanted rice yield and reduce the greenhouse gas emissions

Biaxia lrotary tillage in dryland(DBRT)can complete biaxial rotary tillage with straw incorporation,secondary suppression,and ditching,and it has been previously studied in direct-seeded rice and wheat.However,the effects of DBRT on the mechanically transplanted rice yield and greenhouse gas emissions remain unclear.To evaluate the effects of DBRT on improving the food security of mechanically transplanted rice and reducing the greenhouse gas emissions,we conducted an experiment for two years with wheat straw incorporation.Three tillage methods were set up:DBRT,uniaxial rotary tillage in dryland and paddy(DPURT),and uniaxial rotary tillage in paddy(PURT).The results showed that compared with DPURT and PURT,DBRT increased the yield of machine-transplanted rice by 7.5-11.0%and 13.3-26.7%,respectively,while the seasonal cumulative CH_(4) emissions were reduced by 13.9-21.2%and 30.2-37.0%,respectively,and the seasonal cumulative N_(2)O emissions were increased by 13.5-28.6%and 50.0-73.1%,respectively.Consequently,DBRT reduced the global warming potential by 10.7-15.5%and 23.7-28.6%,respectively,andtheyield-scaledglobalwarmingpotentialby18.2-21.8%and36.4-39.3%,respectively,compared to DPURT and PURT.These results were mainly related to the fact that DBRT significantly reduced soil bulk density and increased soil redox potential(Eh).Therefore,implementing DBRT in machine-transplanted rice fields is feasible,which cannot only increase the rice yield,but also reduce the greenhouse gas emissions.

Effect of No Tillage and Conventional Tillage on Wheat Grain Yield Variability: A Review

Conservation Agriculture(CA)covers more than 205 million hectares in the world.This made it possible to face and mitigate the challenges of climate change,reducing soil erosion and providing multiple ecosystem services.The first elementary factor influenced is the yield evaluation.It has a direct effect on farmers’choices for sustainable production.The present article records a review focused on wheat yield average positive change compared between conventional tillage(CT)and no tillage(NT)systems.The international database collected showed that NT is adaptable everywhere.The results of wheat yield differentiation showed the influence of crop rotation depending on stations located in different climatic zones.In more than 40 years of research,specialists have succeeded in demonstrating the importance of crop productivity like wheat.The whole integrates also experimentations where the initiation starts more than ten years.

Microbial Responses of Soil Fertility to Depth of Tillage and Incorporation of Straw in a Haplic Chernozem in Northeast China

Straw is widely incorporated into soil worldwide,but most studies have concentrated on the effects of straw mulching or incorporation with topsoil.To determine the effect of depth of straw incorporation on bacterial and fungal communities,we established a field experiment in a region in Northeast China with Haplic Chernozems using four treatments:conventional tillage(CT,tillage to a depth of 15 cm with no straw incorporation),straw incorporation with conventional tillage(SCT,tillage to a depth of 15 cm),inversion tillage(IT,tillage to a depth of 35 cm)and straw incorporation with inversion tillage(SIT,tillage to a depth of 35 cm).The soils were managed by inversion to a depth of 15 or 35 cm after harvest.The results show that soil organic carbon content was significantly higher and pH and bulk density were significantly lower in the 15–35 cm layer in IT and SIT than CT and SCT.Fungal abundance was higher with straw incorporation,but fungal diversity was lower in the 0–15 cm layer in SCT and SIT than in CT and IT.Path length in the bacterial network was shorter and connectivity was higher in CT+SCT than in IT+SIT,leading to a more complex ecosystem,and the fungal network had opposite patterns.The key taxa in the phylum Actinobacteriota and Ascomycota in the microbial networks changed dramatically at the genus level following inversion tillage with straw amendment,which may increase bacterial network resistance to environmental disturbances and unstable fungal networks,resulting in large changes in the fungal community involved in the decomposition of recalcitrant straw-derived C and the more efficient acquisition of limiting resources.

Better tillage selection before ridge–furrow film mulch can facilitate root proliferation, and increase nitrogen accumulation,translocation and grain yield of maize in a semiarid area

Plastic film mulch systems are used widely in arid areas, and the associated tillage measures affect soil properties, root and crop growth, and nutrient uptake. However, much debate surrounds the most suitable tillage method for plastic film mulch systems. We conducted a two-year field experiment to explore the impact of three tillage treatments-rotary tillage before ridge–furrow plastic film mulch(MR), no-tillage before ridge–furrow plastic film mulch(MZ), and plow tillage before ridge–furrow plastic film mulch(MP)-on soil total nitrogen, available nitrogen, root stratification structure,nitrogen transfer and utilization, and maize yield. The results showed that MP had better soil quality than either MR or MZ over 2019 and 2020, with higher nitrate-nitrogen and total nitrogen in the 0–40 cm soil layer. MP improved the soil physicochemical properties more than the other treatments, producing significantly higher root numbers and root biomass for the aerial and underground nodal roots than MR and MZ. At harvest, MP had the highest root biomass density,root length density, and root surface area density in the different soil layers(0–20, 20–40, and 0–40 cm). Significant correlations occurred between root biomass and aboveground nitrogen accumulation during maize growth. During grain filling, MP had the greatest nitrogen transfer amount, significantly increasing root and aboveground nitrogen transfer by 19.63–45.82% and 11.15–24.56%, respectively, relative to the other treatments. MP significantly produced 1.36–26.73%higher grain yields and a higher grain crude protein content at harvest than MR and MZ. MP also had higher values for the nitrogen harvest index, nitrogen uptake efficiency, and partial factor productivity of nitrogen fertilizer than MR and MZ.In conclusion, plow tillage combined with a ridge–furrow plastic film mulch system facilitated maize root development and improved nitrogen utilization, thereby increasing maize yield more than the other treatments.

RETRACTED:Effect of Long-Term Inorganic Fertilization on Diversity and Abundance of Bacterial and Archaeal Communities at Tillage in Irrigated Rice Field

Short Retraction Notice The paper does not meet the standards of "Advances in Bioscience and Biotechnology". This article has been retracted to straighten the academic record. In making this decision the Editorial Board follows COPE's Retraction Guidelines. The aim is to promote the circulation of scientific research by offering an ideal research publication platform with due consideration of internationally accepted standards on publication ethics. The Editorial Board would like to extend its sincere apologies for any inconvenience this retraction may have caused. Editor guiding this retraction: Prof. Abass Alavi (EiC of ABB). Please see the article page for more details. The full retraction notice in PDF is preceding the original paper which is marked "RETRACTED".

Technical Efficiency of"Master Switch"in Widening the Human Living Space by Fenlong Tillage

This paper reports"the fourth set"of drilling tillage after"ploughing(hoeing)"by manpower,animal power and tractor——Fenlong tillage technology(referred to as"Fenlong technology").It makes the cultivated land and saline alkali land transformed into"sponge"farmland through"drill bit"vertically digging into the soil,one-time deep cultivation,not disturbing soil layer,and granulating the soil,to bring about the effects of"expanding the land,releasing the natural force,water conservation,disaster reduction,carbon reduction,tillage saving,fertilizer saving and grain increasing",and can broaden the space for human survival and development.It has been applied to more than 50 crops in 28 provinces,including Guangxi,Hebei and Tibet.Without increasing the use of fertilizer and water,the yield of varieties in cultivated land increased by 10%-50%,while that in saline and alkaline land increased by 20%-100%.The storage of natural precipitation increased by 100%,and drought,high temperature and low temperature decreased by 20%-30%,and carbon sequestration and emission reduction reached 20%.It is proposed that China can implement the"dual strategy"platform of farmland,saline alkali land,rivers and water bodies constructing the"incremental""five new warehouses"of grain,water,fish,sugar,etc.and"increased grain return"abroad,to ensure national security.

Effects of Tillage Depth on Nutrients and Microbial Communities in Tobacco-Planting Soil

The implementation of appropriate tillage practices is of great significance for agricultural production. However, the effects of different tillage depths on soil nutrients content and microbial communities in tobacco-planting soils are still lacking systematic research. In this study, three different tillage depths of 15 cm (T1), 20 cm (T2), and 30 cm (T3) were set up for field experiments in Liupanshui, Guizhou Province, to explore the effects of tillage depth on tobacco-planting soil nutrients and bacterial and fungal communities based on 16S rRNA and ITS sequencing and figure out the key factors affecting soil microbial communities. The results showed that T2 and T3 increased the contents of organic matter, total nitrogen, total phosphorus, available phosphorus, and available potassium in tobacco-planting soil, and increased the diversity of bacterial communities compared with T1. There was no significant difference in the structure of bacterial and fungal communities in different tillage depth treatments, but some dominant genera were significantly enriched in T2 and T3. Desulfobacter, Setophoma, Humicola, and Acremonium were significantly enriched in T2. Chthonomonas and Fusarium were significantly enriched in T3. These genera favor the decomposition of organic matter and the cycling of nutrients, and control soil pests and diseases. Redundancy analysis indicated that TP and AK were the key factors influencing the dominant genera of bacteria and fungi. This study provides a scientific basis for the selection of soil tillage depth for tobacco production in this region.

Evaluating the Impact of Different Tillage Regimes and Nitrogen Levels on Yield and Yield Components of Maize (Zea mays L.)

A field study to evaluate the impact of different tillage regimes and nitrogen levels on yield and yield components of maize (Zea mays L.), was conducted during autumn 2014 at Students Farm, Department of Agronomy, University of Agriculture, Faisalabad. The experiment was laid out in RCBD (Randomized Complete Block Design), with split plot arrangement having three replications. The experiment was comprised of three tillage regimes (Minimum, Conventional and Deep) and three nitrogen levels viz: 100, 200 and 300 kg•ha-1. Urea was used as a source of nitrogen, sulphate of potash as a source of potassium and triple super phosphate as a source of phosphorous. The amount of phosphorous and potash was constant in all the treatments i.e. 125 kg•ha-1 and 100 kg•ha-1 respectively. Results of present study are summarized as yield parameters are significantly affected by different nitrogen levels and tillage regimes. Maximum number of plants at harvest (7.93), number of grain rows per cob (17.70), number of grains per row (34.31), number of grains per cob (678.58), and cob weight (187.50 g) were observed in deep tillage at 200 kg•ha-1 nitrogen application. 1000-grain weight (275.52 g), biological yield (15.66 t•ha-1), grain yield (6.16 t•ha-1) and dried stalk yield (9.91 t•ha-1) were observed maximum in deep tillage at 200 kg•ha-1 nitrogen application. Harvest index significantly affected by tillage regimes and maximum harvest index (39.58%) were recorded in deep tillage which was statistically at par with conventional tillage (38.83%). It was concluded that higher grain yield of maize can be obtained by deep tillage with the application of 200 kg•ha-1 nitrogen application under the prevailing conditions of Faisalabad.

Genotype×tillage interaction and the performance of winter bread wheat genotypes in temperate and cold dryland conditions

Growing concerns for food security and the alleviation of hunger necessitate knowledge-based crop management technologies for sustainable crop production.In this study,13 winter bread wheat genotypes(old,relatively old,modern,and breeding lines)were evaluated under three different tillage systems,i.e.,conventional tillage(CT,full tillage with residue removed),reduced tillage(RT,chisel tillage with residue retained)and no-tillage(NT,no-tillage with residue retained on the soil surface)in farmer’s fields under rainfed conditions using strip-plot arrangements in a randomized complete block design with three replications in the west of Iran(Kamyaran and Hosseinabad locations)over two cropping seasons(2018–2019 and 2019–2020).The main objectives were to investigate the effects of tillage systems and growing conditions on the agronomic characteristics,grain yield and stability performance of rainfed winter bread wheat genotypes.Significant(P<0.01)genotype×tillage system interaction effects on grain yield and agronomic traits suggested that the genotypes responded differently to the different tillage systems.The number of grains per spike and plant height were positively(P<0.0)associated with grain yield under the NT system,so they may be considered as targeted traits for future wheat breeding.Using statistical models,the modern cultivars(“Sadra”and“Baran”)were identified as high yielding and showed yield stability across the different tillage systems.As per each tillage system,genotype“Sadra”followed by“Zargana-6//Dari 1-7 Sabalan”exhibited higher adaption to CT;while cultivars“Jam”and“Azar2”showed better performance under the RT system;and cultivars“Varan”and“Baran”tended to have better performance expression in the NT condition.The increased grain yields achieved in combination with lower costs and greater profits from conservation agriculture suggest that adapted cultivar and NT systems should be evaluated and promoted more widely to farmers in the west of Iran as an attractive package of crop management technologies.In conclusion,variations in the performance of genotypes and the significant genotype×tillage system interaction effects on grain yield and some agronomic traits assessed in this study suggest that the development and selection of cultivars adapted to the NT system should be considered and included in the strategies and objectives of winter wheat breeding programs for the temperate and cold dryland conditions of Iran.

Effects of Five Years Adoption of No-Tillage Systems for Vegetables Crops in Soil Organic Matter Contents

Vegetables productions systems are done normally with intense soil tillage causing a strong decline of soil quality. Use of conservation systems can be an alternative to recover this quality. In order to evaluate the effects of such systems on soil organic matter, an experiment has been conducted in randomized blocks design and factorial scheme 3 × 2: three soil management systems (no-tillage;reduced tillage and conventional tillage) and two cover crops (maize single;and intercropping maize with gray velvet bean—Stizolobium niveum);and repeated measures over time. Soil samples were collected before the implementation of the experiment and at the end of each crop cycle until the fifth crop cycle. Carbon associated with humic substances is also determined in 0 - 5 cm, 5 - 10 cm and 10 - 30 cm at the end of the last crop cycle. The SOM content was higher in RT (48.34 g·kg-1) than in the CT (39.48 g·kg-1) at the end of the fifth crop cycle. SOM content in NT (44.92 g·kg-1) was statistically equal to RT and CT, during the same period. In 0 - 5 cm, carbon contents associated to the humic substances present the same behavior of SOM contents in 0 - 10 cm. Probably these results are associated with the capacity of each system to improve superficial contents of SOM stable fractions. It follows that the conservation systems used are alternatives to the cultivation vegetables in order to improve soil organic matter contents.

Effect of subsoil tillage depth on nutrient accumulation, root distribution, and grain yield in spring maize

A four-year field experiment was conducted to investigate the effect of subsoiling depth on root morphology, nitrogen(N), phosphorus(P), and potassium(K) uptake, and grain yield of spring maize. The results indicated that subsoil tillage promoted root development,increased nutrient accumulation, and increased yield. Compared with conventional soil management(CK), root length, root surface area, and root dry weight at 0–80 cm soil depth under subsoil tillage to 30 cm(T1) and subsoil tillage to 50 cm(T2) were significantly increased, especially the proportions of roots in deeper soil. Root length, surface area, and dry weight differed significantly among three treatments in the order of T2 > T1 > CK at the12-leaf and early filling stages. The range of variation of root diameter in different soil layers in T2 treatment was the smallest, suggesting that roots were more likely to grow downwards with deeper subsoil tillage in soil. The accumulation of N, P, and K in subsoil tillage treatment was significantly increased, but the proportions of kernel and straw were different. In a comparison of T1 with T2, the grain accumulated more N and P, while K accumulation in kernel and straw varied in different years. Grain yield and biomass were increased by 12.8% and 14.6% on average in subsoil tillage treatments compared to conventional soil treatment. Although no significant differences between different subsoil tillage depths were observed for nutrient accumulation and grain yield, lodging resistance of plants was significantly improved in subsoil tillage to 50 cm, a characteristic that favors a high and stable yield under extreme environments.

Soil physical properties and maize root growth under different tillage systems in the North China Plain

The standard cultivation system in the North China Plain is double cropping of winter wheat and summer maize. The main effects of this cultivation system on root development and yield are decreases in soil nutrient content and depth of the plow layer under either long-term no-tillage or rotary tillage before winter wheat sowing and no tillage before summer maize sowing. In this study, we investigated the combined effects of tillage practices before winter wheat and summer maize sowing on soil properties and root growth and distribution in summer maize. Zhengdan 958(ZD958) was used as experimental material, with three tillage treatments: rotary tillage before winter wheat sowing and no tillage before summer maize sowing(RTW + NTM), moldboard plowing before winter wheat sowing and no tillage before summer maize sowing(MPW + NTM), and moldboard plowing before winter wheat sowing and rotary tillage before summer maize sowing(MPW + RTM).Tillage practice showed a significant(P < 0.05) effect on grain yield of summer maize. Grain yields under MPW + RTM and MPW + NTM were 30.6% and 24.0% higher, respectively, than that under RTW + NTM. Soil bulk density and soil penetration resistance decreased among tillage systems in the order RTW + NTM > MPW + NTM > MPW + RTM. Soil bulk densities were 3.3% and 515% lower in MPW + NTM and MPW + RTM, respectively, than that in RTW + NTM, and soil penetration resistances were respectively 17.8% and 20.4% lower,across growth stages and soil depths. Root dry matter and root length density were highest under MPW + RTM, with the resulting increased root activity leading to a yield increase of summer maize. Thus the marked effects of moldboard plowing before winter-wheat sowing on root length density, soil penetration resistance, and soil bulk density may contribute to higher yield.

Effects of deep vertical rotary tillage on the grain yield and resource use efficiency of winter wheat in the Huang-Huai-Hai Plain of China

Tillage represents an important practice that is used to dynamically regulate soil properties,and affects the grain production process and resource use efficiency of crops.The objectives of this 3-year field study carried out in the Huang-Huai-Hai(HHH) Plain of China were to compare the effects of a new deep vertical rotary tillage (DVRT) with the conventional shallow rotary tillage (CT) on soil properties,winter wheat (Triticum aestivum L.) grain yield and water and nitrogen use efficiency at different productivity levels,and to identify a comprehensive management that optimizes both grain yield and resource use efficiency in the HHH Plain.A split-plot design was adopted in field experiments in the winter wheat growing seasons of 2016–2017 (S1),2017–2018 (S2) and 2018–2019 (S3),with DVRT (conducted once in June 2016) and CT performed in the main plots.Subplots were treated with one of four targeted productivity level treatments (SH,the super high productivity level;HH,the high productivity and high efficiency productivity level;FP,the farmer productivity level;ISP,the inherent soil productivity level).The results showed that the soil bulk density was reduced and the soil water content at the anthesis stage was increased in all three years,which were due to the significant effects of DVRT.Compared with CT,grain yields,partial factor productivity of nitrogen (PFP_(N)),and water use efficiency (WUE) under DVRT were increased by 22.0,14.5 and 19.0%.Path analysis and direct correlation decomposition uncovered that grain yield variation of winter wheat was mostly contributed by the spike numbers per area under different tillage modes.General line model analysis revealed that tillage mode played a significant role on grain yield,PFP_(N) and WUE not only as a single factor,but also along with other factors(year and productivity level) in interaction manners.In addition,PFP_(N) and WUE were the highest in HH under DVRT in all three growth seasons.These results provided a theoretical basis and technical support for coordinating the high yield with high resource use efficiency of winter wheat in the resource-restricted region in the HHH Plain of China.

Effects of different tillage and straw retention practices on soil aggregates and carbon and nitrogen sequestration in soils of the northwestern China

Soil tillage and straw retention in dryland areas may affect the soil aggregates and the distribution of total organic carbon. The aims of this study were to establish how different tillage and straw retention practices affect the soil aggregates and soil organic carbon(SOC) and total nitrogen(TN) contents in the aggregate fractions based on a long-term(approximately 15 years) field experiment in the semi-arid western Loess Plateau, northwestern China. The experiment included four soil treatments, i.e., conventional tillage with straw removed(T), conventional tillage with straw incorporated(TS), no tillage with straw removed(NT) and no tillage with straw retention(NTS), which were arranged in a complete randomized block design. The wet-sieving method was used to separate four size fractions of aggregates, namely, large macroaggregates(LA, >2000 μm), small macroaggregates(SA, 250–2000 μm), microaggregates(MA, 53–250 μm), and silt and clay(SC, <53 μm). Compared to the conventional tillage practices(including T and TS treatments), the percentages of the macroaggregate fractions(LA and SA) under the conservation tillage practices(including NT and NTS treatments) were increased by 41.2%–56.6%, with the NTS treatment having the greatest effect. For soil layers of 0–5, 5–10 and 10–30 cm, values of the mean weight diameter(MWD) under the TS and NTS treatments were 10.68%, 13.83% and 17.65%, respectively. They were 18.45%, 19.15% and 14.12% higher than those under the T treatment, respectively. The maximum contents of the aggregate-associated SOC and TN were detected in the SA fraction, with the greatest effect being observed for the NTS treatment. The SOC and TN contents were significantly higher under the NTS and TS treatments than under the T treatment. Also, the increases in SOC and TN levels were much higher in the straw-retention plots than in the straw-removed plots. The macroaggregates(including LA and SA fractions) were the major pools for SOC and TN, regardless of tillage practices, storing 3.25–6.81 g C/kg soil and 0.34–0.62 g N/kg soil. Based on the above results, we recommend the NTS treatment as the best option to boost soil aggregates and to reinforce carbon and nitrogen sequestration in soils in the semi-arid western Loess Plateau of northwestern China.

Yield and tillering response of super hybrid rice Liangyoupeijiu to tillage and establishment methods

Tillering is an important agronomic trait for rice grain production. To evaluate yield and tillering response, Liangyoupeijiu(super hybrid rice) was grown in Hunan, China during 2011–2012 under different methods of tillage(conventional and no-tillage system) and crop establishment methods(transplanting at a spacing of 20 cm × 20 cm with one seedling per hill and direct seeding at a seeding rate of 22.5 kg ha-1). Our results revealed that, at maximum tillering(Max.) and at maturity(MA) stages, direct seeding(DS) resulted in 22% more tillers than transplanting(TP) irrespective of tillage system. Tiller mortality reached a peak between panicle initiation(PI) and booting(BT) stages, and was 16% higher under conventional tillage(CT) than under no-tillage(NT). Transplanting required 29% more time for the completion of tillering and less for DS. Tillering rate was 43% higher in DS than TP under either CT or NT. There was a positive correlation between panicle number per m2and maximum tiller number per m2, but not panicle-bearing tiller rate. The panicle bearing tiller rate was higher under DS than TP and higher under NT than CT. Tiller dry weight gradually increased up to heading(HD) stage, and was 14% higher under TP than DS. Leaf area(cm2tiller-1) gradually increased from Max. to HD stage and then decreased by 34% in conventional tillage transplanting(CTTP) and 45% in no-tillage transplanting(NTTP) from 12DAH–24DAH(days after heading), but was similar(35%) under DS under either CT or NT. Grain yield was higher under CTTP owing to the larger sink size(heavier panicle, more spikelets in per cm length of panicle) than under DS.

Strip rotary tillage with subsoiling increases winter wheat yield by alleviating leaf senescence and increasing grain filling

Sustainable agriculture in the Huang–Huai–Hai Plain of China is threatened by subsoil compaction and the decline of winter wheat productivity induced by inappropriate tillage regimes. We investigated the effects of optimizing the tillage regime on grain filling and its relationship with flag leaf senescence post-anthesis in winter wheat. Four treatments were compared: rotary tillage, strip rotary tillage, strip rotary tillage with a 2-year subsoiling interval(STS), and conventional plowing tillage. STS produced higher chlorophyll content and leaf area indexes than other treatments, resulting in a greater photosynthetically active radiation capture ratio. The net photosynthesis rate of flag leaves from 14 to 28 days after anthesis and dry matter accumulation at maturity were higher in STS than in other treatments. Sucrose content and sucrose phosphate synthase activity of flag leaves first increased and then decreased during grain filling and were highest in STS. STS increased superoxide dismutase activity, increased soluble protein content, and reduced malondialdehyde concentrations in flag leaves after the middle grain-filling stages,resulting in reduced premature senescence. This consequence extended the active grain filling period and increased grain weight. The highest yields were observed in STS, reaching10,451 kg ha-1 in 2014–2015 and 10,074 kg ha-1 in 2015–2016, owing to increased spike numbers and 1000-kernel weight. Overall, our study suggested that STS could substantially increase photosynthetic capacity and delay leaf senescence, thus promoting grain filling rate and increasing winter wheat yields.

Distribution of soil aggregates and organic carbon in deep soil under long-term conservation tillage with residual retention in dryland

To ascertain the effects of long-term conservation tillage and residue retention on soil organic carbon(SOC) content and aggregate distribution in a deep soil(>20-cm depth) in a dryland environment,this paper analyzed the SOC and aggregate distribution in soil, and the aggregate-associated organic carbon(OC) and SOC physical fractions. Conservation tillage(reduced tillage with residue incorporated(RT) and no-tillage with residue mulch(NT)) significantly increased SOC sequestration and soil aggregation in deep soil compared with conventional tillage with residue removal(CT). Compared with CT, RT significantly increased the proportion of small macroaggregates by 23%–81% in the 10–80 cm layer, and the OC content in small macroaggregates by 1%–58% in the 0–80 cm layer. RT significantly increased(by 24%–90%) the OC content in mineral-SOC within small macroaggregates in the 0–60 cm layer, while there was a 23%–80% increase in the 0–40 cm layer with NT. These results indicated that:(1) conservation tillage treatments are beneficial for soil aggregation and SOC sequestration in a deep soil in a dryland environment; and(2)the SOC in mineral-associated OC plays important roles in soil aggregation and SOC sequestration. In conclusion, RT with NT is recommended as an agricultural management tool in dryland soils because of its role in improving soil aggregation and SOC sequestration.

Effect of Tillage and Nitrogen on Wheat Production, Economics, and Soil Fertility in Rice-Wheat Cropping System

Conservation tillage and nitrogen may improve soil fertility, yield and income on sustainable basis. The aim of this study was to evaluate the impact of three tillage systems viz. zero (ZT), reduced (RT), and conventional tillage (CT) and five N rates (0, 80, 120, 160, and 200 kg·N·ha-1) on yield and yield components, soil organic matter (SOM), total soil N (TSN), and income of wheat (Triticum aestivum L.) grown after rice (Oryza sativa L.). Nitrogen rates significantly affected yield and yield attributing characters with highest values recorded at200 kg·N·ha-1. Mean maximum grain yield (6390 -6845 kg·ha-1), net benefit (1359 - 1460 US$ ha-1), and benefit cost ratio (5.6 - 5.7) could be achieved at 160 to200 kg·N·ha-1. The tillage systems produced similar yield and yield components except spikes m-2. The SOM and TSN were highest in ZT compared to other tillage systems. Though tillage × N interactions were not significant for most of the parameters under study, the overall effect of ZT with200 kg·N·ha-1 appeared to be most favorable compared to RT and CT. Zero tillage resulted in highest number of spikes m-2 (304.4), SOM (9.6 g·kg-1) and TSN (0.5 g·kg-1) with200 kg·N·ha-1. The results suggest that ZT with200 kg·N·ha-1 was optimum and sustainable strategy to achieve higher yield and income and also to improve SOM and TSN on silty clay soil.

Effects of Straw Returning with Different Tillage Patterns on Corn Yield and Nitrogen Utilization

To explore the effects of farming methods,straw returning and their interaction on corn yield and nitrogen utilization,the experiment was conducted for two consecutive years from 2016 to 2017 at the Xiangyang Experimental Base of Northeast Agricultural University in Heilongjiang Province of China.The method of combining farming with straw returning was used and six treatments as rotary tillage(R)+no straw returning(K),rotary tillage(R)+straw returning(S),tillage(T)+no straw returning(K),tillage(T)+straw returning(S),tillage(T)+subsoiling(D)+no straw returning(K)and tillage(T)+subsoiling(D)+straw returning(S)were set to study the effects of different tillage methods and straw returning on corn yield and nitrogen accumulation and utilization.The corn yield,nitrogen accumulation,nitrogen transport,grain weight and dry matter accumulation of tillage(T)+subsoiling(D)and tillage(T)were significantly higher than those of rotary tillage(R)treatment.Meanwhile,the corn yield,nitrogen accumulation and dry matter accumulation of TD treatment were significantly higher than those of T treatment;the corn yield,dry matter accumulation,kernel weight,nitrogen dry matter production efficiency and nitrogen grain production efficiency of S treatment were significantly higher than those of K treatment.Among the treatments,the yield,nitrogen accumulation and utilization efficiency of TDS,TS and TDK were the highest.The yield,nitrogen accumulation and nitrogen transport of TDS were significantly higher than those of TS.In 2016,TDS production increased by 7.30%and 8.20%compared with TS;and TDS nitrogen accumulation increased by 6.78%and 9.50%compared with TS,while the yield and nitrogen grain production efficiency were significantly higher than those of TDK.Therefore,under the conditions of this experiment,on the basis of straw returning,tillage+subsoiling was the suitable farming method.