Tillage Regimes Research Articles

Microbial community alteration driven by labile organic carbon enhances phosphorus availability under different tillage regimes

Microbial community alteration driven by labile organic carbon enhances phosphorus availability under different tillage regimes

Evaluation of rabi season sesame productivity from graded nutrient doses and tillage regimes in rice fallows of southern plateau and hills region of the Indian sub-continent.

Only scattered information is available on the tillage and nutrient management information for the sesame crop following rice in the literature. Sesame as an edible oil yielding crop with high levels of unsaturated fatty acids has high international demand due to superior health benefits. Being a small seeded crop, it requires standard tillage and nutrient management to obtain optimum productivity under rice fallow ecologies. As a sequential crop after rice harvest, the tillage and nutrient management practices followed for the preceding rice have astounding effects on the succeeding sesame crop. To better understand and manipulate the agro ecology in the rice fallow culture, it is necessary to study the behaviour of sesame cultivars, in relation to the tillage requirements and macro nutrient factors that have a bearing on the productivity. The aim of this work was to evaluate the productivity of rice fallow sesame in the southern plateau and hills regions of the Indian sub-continent (Tamil Nadu) with a hypothesis that tillage and nutrient management would immensely benefit the sesame crop. Field experiments were conducted at TNAU, Tamil Nadu Rice Research Institute, Aduturai, Tamil Nadu during 2019-2020 and 2020-2021 with tillage practices (reduced tillage, conventional tillage and zero tillage) and fertilizer doses (zero percent RDF, 25% RDF, 50% RDF, 75% RDF and 100% RDF) in a split plot design replicated thrice. The results have clearly indicated that the performance of rice fallow sesame was poor under zero till conditions as the sesame crop is poorly adapted leading to a yield penalty up to 68%. A total of 75% RDF has yielded statistically similar yield to that of 100% RDF to the rice fallow sesame. Further, neither the oil content nor the fatty acid composition was modified by tillage and nutrient management regimes.

Primary Non-Inversion Shallow Tillage Versus Moldboard Plowing Prior to Growing Potatoes: Short-Term Impacts on Potato Yield and Soil Properties in Eastern Canada

Potato (Solanum tuberosum L.) production often requires intensive tillage with the moldboard plow (MP), which involves deeper soil tillage and turning of the soil to provide enough loose soil for proper tuberization. Although tillage with the MP allows better potato seedbed preparation and lower weed pressure, it is also associated with increased soil compaction, soil aggregate destruction, and increased soil organic matter (SOM) mineralization. The objective of this four-year (2019–2022) study conducted in 14 commercial fields was to compare the use of MP with primary non-inversion shallow tillage (ST) in terms of their effect on selected soil health indicators, soil moisture, potato petiole nitrate concentration, potato yield, and specific gravity. Commercial fields ranged from 1.5 ha to 19 ha where the main field was split in half, with one side tilled using MP (22.5–30 cm plowing depth) and the other half using ST (15–30 cm plowing depth). Soil and plant tissue samples were taken within four sub-replicates (91 m2) created per each treatment per each site and three to four sites were used as replicates per each year. Compared to MP, ST increased active carbon by an average of 9%, soil respiration by an average of 26%, and aggregate stability by an average of 8%. Biological N availability (BNA) increased by an average of 20% with ST, and the effect was statistically significant in three out of four years. Soil moisture at 20 cm depth tended to be higher with MP than ST in three out of four years. Although not statistically significant, when averaged across four years, potato petiole nitrate concentrations were 5% and 12% higher with ST than MP in samples collected at the flowering and post-potato flowering stages, respectively. Total and marketable potato yields, along with specific gravity, were comparable for the two tillage regimes. Signs of soil improvement were observed at the early stages of ST adoption. Marketable yield was negatively correlated with the soil nitrate levels measured during the growing season but was positively correlated with active carbon, aggregate stability, and soil moisture. Future studies could compare both tillage regimes over multiple growing seasons to assess their impacts over a full cycle of rotation. The novelty of the present study was that it was conducted in real-life conditions across large growers’ fields with different conditions and across four years.

Reduced tillage intensity does not increase arbuscular mycorrhizal fungal diversity in European long‐term experiments

AbstractMechanical soil disturbance is one among the key factors influencing soil biodiversity in agriculture. Although many soil organisms are sensitive to soil disturbance, fungi could be highly impacted due to their sessile lifestyle, relatively slow growth and filamentous body structure. Arbuscular mycorrhizal (AM) fungi are of particular interest in arable lands, providing crop plants with numerous vital services such as nutrient acquisition and protection against abiotic and biotic stressors. Considering this, tillage practices that aim to reduce soil disturbance are often seen as a fungal‐friendly alternative to conventional inversion tillage. Although local studies exist on the impacts of minimal tillage practices on AM fungi, the universality of this approach has been debated. Our objective was to assess the effects of reduced tillage intensity on AM fungi in comparison with conventional tillage. Using high‐throughput sequencing techniques in long‐term field experiments in five European countries, we show that the effects of reduced tillage intensity may not necessarily be positive on soil AM fungal diversity. Plots which were tilled using reduced tillage techniques had lower AM fungal richness in three countries, whereas in one of them, no significant differences were found. We also observed a shift in AM fungal communities where prevalence of taxa preferring root colonisation rather than soil exploration increased under reduced tillage regimes. Here, we argue that more detailed and long‐term studies are needed to understand the factors that could make the reduction of soil disturbance more beneficial to AM fungi if agricultural sustainability goals are to be met.

The content and quality of soil carbon and nitrogen as well as enzymatic activity in soils with diverse texture following different land use and management practices

AbstractA detailed knowledge concerning the responses of different carbon pools and the activity of soil enzymes to various land uses is critical for maintaining soil health and quality. Accordingly, the aim of this study was to determine the effects of different soil uses and management practices on the contents of total, dissolved and microbial biomass C and N as well as the fractional composition of humus and the set of enzyme activities. This study was conducted to compare the status of soil properties in the surface horizons of 24 soils with diverse textures, following the different land uses. Thus, arable lands, short‐term cultivation, vineyards, orchards, hop plantations and grasslands were compared. The contents of total and dissolved carbon and nitrogen, the fractional composition of humus, the content of microbial biomass C and N and the enzymatic activity were assessed. The application of various land uses affects the C and N content of the soils and their humus fractions as well as their enzymatic activities differently. Generally, both grass‐based systems (grasslands and orchards) revealed the most positive effects in most of the studied properties as compared to other land use systems. By contrast, long‐term tillage and/or the lack of permanent plant cover (cereals, grapevine and hop cultivation) adversely affects the studied properties of the soils. No clear pattern of changes was detected in terms of the fractional composition of the SOM. The enzymatic activity changed because of their different functions in SOM transformation and because of the differences in the complexities of the enzymatic substrates occurring in the soil. Most of the studied properties were significantly higher in soils with a loamy texture as compared to the sandy loam and loamy sand soils. Differently managed soils presented a distinctive response in terms of organic matter content and quality as well as extracellular enzyme activity as a function of the tillage regime applied and different cultivated plants. In general terms, both land uses which were based on permanent grass cultivation revealed that the most positive effects occurred on these studied properties as compared to other land use systems. Therefore, we may conclude that permanent grasslands play a special role in the status of soil organic matter, microbial content and enzymatic activity.

Conservation tillage: a way to improve yield and soil properties and decrease global warming potential in spring wheat agroecosystems.

Climate change is one of the main challenges, and it poses a tough challenge to the agriculture industry globally. Additionally, greenhouse gas (GHG) emissions are the main contributor to climate change; however, croplands are a prominent source of GHG emissions. Yet this complex challenge can be mitigated through climate-smart agricultural practices. Conservation tillage is commonly known to preserve soil and mitigate environmental change by reducing GHG emissions. Nonetheless, there is still a paucity of information on the influences of conservation tillage on wheat yield, soil properties, and GHG flux, particularly in the semi-arid Dingxi belt. Hence, in order to fill this gap, different tillage systems, namely conventional tillage (CT) control, straw incorporation with conventional tillage (CTS), no-tillage (NT), and stubble return with no-tillage (NTS), were laid at Dingxi, Gansu province of China, under a randomized complete block design with three replications to examine their impacts on yield, soil properties, and GHG fluxes. Results depicted that different conservative tillage systems (CTS, NTS, and NT) significantly (p < 0.05) increased the plant height, number of spikes per plant, seed number per meter square, root yield, aboveground biomass yield, thousand-grain weight, grain yield, and dry matter yield compared with CT. Moreover, these conservation tillage systems notably improved the soil properties (soil gravimetric water content, water-filled pore space, water storage, porosity, aggregates, saturated hydraulic conductivity, organic carbon, light fraction organic carbon, carbon storage, microbial biomass carbon, total nitrogen, available nitrogen storage, microbial biomass nitrogen, total phosphorous, available phosphorous, total potassium, available potassium, microbial counts, urease, alkaline phosphatase, invertase, cellulase, and catalase) while decreasing the soil temperature and bulk density over CT. However, CTS, NTS, and NT had non-significant effects on ECe, pH, and stoichiometric properties (C:N ratio, C:P ratio, and N:P ratio). Additionally, conservation-based tillage regimes NTS, NT, and CTS significantly (p < 0.05) reduced the emission and net global warming potential of greenhouse gases (carbon dioxide, methane, and nitrous oxide) by 23.44, 19.57, and 16.54%, respectively, and decreased the greenhouse gas intensity by 23.20, 29.96, and 18.72%, respectively, over CT. We conclude that NTS is the best approach to increasing yield, soil and water conservation, resilience, and mitigation of agroecosystem capacity.

Carbon Footprint of Wheat and Maize: A Greek Case Study

Wheat and maize are two of the most dominant crops of considerable importance in human nutrition. At the same time, agriculture is responsible for about 1/3 of anthropogenic greenhouse gas emissions. The aim of this study is to estimate the carbon footprint of the two aforementioned important crops in the region of Larissa, Greece. Under this context, the emitted CO2eq- per kg of product, the corresponding emissions per hectare and per g of harvested plant protein were estimated. The carbon footprint was measured using the CoolFarm Tool (Cool Farm Alliance). Data were collected through questionnaires and interviews with local farmers. According to the results, the carbon footprint per hectare in maize (2,979 kg CO2eq- ha-1) is significantly higher compared to wheat (1,090 kg CO2eq- ha-1). In contrast, the differences in the footprints per kilogram of product and per g of harvested protein were insignificant. Tillage was found to be the main factor increasing CO2eq- emissions in both crops. In this research work we demonstrated that tillage regimes are crucial for mitigating agricultural related GHG emissions.

Earthworm communities and their relation to above‐ground organic residues and water infiltration in perennial cup plant (Silphium perfoliatum) and annual silage maize (Zea mays) energy plants

AbstractPerennial energy cropping systems are hailed as a sustainable way of mitigating and potentially adapting to climate change. As a result of the absence of tillage, soils cropped with perennials like cup plant (Silphium perfoliatum) promote abundant and functionally diverse earthworm communities. Hence, ecosystem service provision because of earthworm activity and functional redundancy, for example, litter decomposition, water infiltration and nutrient turnover, is considerably enhanced in perennial cropping systems. We studied the abundance and functional role of earthworms in non‐tilled perennial systems and reduced‐tilled annual systems to assess their relationship with the respective above‐ground organic residues and their implications for the soil water dynamic. We sampled earthworms and simultaneously measured the saturated infiltration rate for two consecutive years in cup plant and maize (Zea mays) fields. Furthermore, we sampled above‐ground litter each trimester in both systems and analysed the total C and N content and CN ratios. Our field investigations revealed significantly higher earthworm abundance, species diversity and richness in cup plant systems likely because of the absence of tillage and the formation of a litter layer. High abundances of juveniles in both maize and cup plant systems pointed to harsh habitat conditions likely because of temperature variations, waterlogging and bulk density. The respective field litter was of minor importance as a food source in both systems because of poor quality, but may positively affect the soil water balance in cup plant systems. Earthworm populations in maize may have been supported by organic fertilizer while earthworm populations in cup plants may have additionally benefitted from the extensive root network and a higher on‐site plant diversity. Reduced tillage regimes in maize systems may have enhanced saturated infiltration rates. A direct link between earthworms and infiltration was not validated, but may not be excluded in the future, as earthworm populations may develop slowly because of adverse habitat conditions. Our results show that perennials support abundant and diverse earthworm populations and indicate the importance of functional redundancy and the diversity of food sources. The combination of both earthworm abundance and perennial cropping systems is capable of increasing on‐site ecosystem stability and supporting adaptation to climate change by increasing functional redundancy and, ultimately, providing ecosystem services. The noticeable occurrence of the latter, however, may be delayed because of the slow establishment of earthworm communities and delayed build‐up of ecosystems stability. Hence, a transitional phase is inevitable to reap the benefits of perennial energy cropping systems and must be accounted for.

Effects of intercropping on soil greenhouse gas emissions - A global meta-analysis

Diversified cropping systems, such as intercropping, have shown multifunctionality in agronomic productivity promotion, pest control, and soil health improvement. However, the intense interaction between crop species stimulates soil carbon and nitrogen turnover, and intercropping systems cause inexplicit effects on soil greenhouse gas emissions (GHG). Therefore, a comprehensive meta-analysis using 52 published articles (531 paired observations) was conducted to elucidate the effects of intercropping on soil N2O, CO2, and CH4 emissions under different environmental conditions and field practices to identify the primary driving factors, such as climate, soil and field practices. The results showed that intercropping treatment had a non-significant impact on the three GHG emissions on average. However, using a cereal-legume intercropping regime, adopting moderate N application rate or intercropping in alkaline soils could significantly mitigate soil N2O emission. Additionally, intercropping in soils with high soil organic carbon reduce soil CH4 emission. On the contrary, increasing intercropping duration, or adopted in soils with moderate soil total N tended to stimulate CO2 emission. The mixed-effect model selection indicated that initial soil pH, MAP, MAT, tillage regime, and intercropping duration and type were significant moderators in regulating soil GHG emissions. Our findings explicitly elucidated soil GHG responses to intercropping practice. Further studies are warranted on the evaluation of long-term intercropping effects to improve the comprehensive understanding of C and N balance and global warming potential under intercropping.

Management of soil cover and tillage regimes in upland rice-sweet corn systems for better system performance, energy use and carbon footprints

This study investigates the effects of tillage and mulching regimes on rice-sweet corn systems in the lower Gangetic plains, focusing on region-specific and crop-specific impacts on soil-crop-environmental parameters. The experiment consisted of three levels of tillage: conventional (CT), minimum (MT), and zero (ZT), and four levels of mulching: live, leaf litter, paddy straw, and no mulching. The results show that ZT tillage resulted in higher bulk density (BD) compared to other treatments, despite an increase in soil organic carbon (SOC). Live and leaf litter mulching led to slight reductions in BD in the upper soil layers. CT resulted in net depletion of SOC whereas ZT registered a positive sequestration rate of 1.19 Mg ha−1 yr−1. Live and leaf litter mulching increased SOC sequestration by 42.6% and 38.8% compared to paddy straw mulching, respectively. Initially, ZT resulted in a 10.3% reduction in system productivity compared to CT, while MT yields were comparable to CT. However, mulching regimes consistently improved production by 16.4%–25.2% as compared to no mulch. ZT and MT were found to be more affordable than CT, with cost savings of 18.2% and 6.8%, respectively. ZT had the highest B: C ratio, indicating better economic efficiency. Among the mulching treatments, live mulching was the most economical. Both ZT and MT saved input energy by approximately 22.9% and 13.5%, respectively compared to CT. Live mulching resulted in the highest net energy and energy output. Compared to CT, ZT reduced carbon footprint (CF) by 41.5 and 22.2% in rice and sweet corn, respectively. MT scored midway between ZT and CT in all parameters. CT exhibited several limitations, including high input energy requirements, high cost of cultivation, poor economic efficiency, negative environmental impacts, and loss of SOC. ZT initially experienced yield reduction and lower net returns in the early years. Therefore, MT was identified as the best alternative in the initial years before transitioning completely to ZT, as it provided comparable yields to CT with better overall benefits. Among the soil cover regimes, live mulching was found to be the most favorable option across all dimensions.

Effects of tillage regime on soil aggregate-associated carbon, enzyme activity, and microbial community structure in a semiarid agroecosystem

Effects of tillage regime on soil aggregate-associated carbon, enzyme activity, and microbial community structure in a semiarid agroecosystem

Weed communities after decades of mineral fertilization and tillage treatments in a corn–soybean rotation

Abstract Soil fertility and disturbance can potentially modify weed dynamics in a corn–soybean rotation. Knowing how added mineral fertilizers and tillage influence weed populations in the long term can provide insight into weed community shifts, which may affect future weed management requirements. The first objective of this study was to evaluate the effect of 24 to 25 years of nitrogen and phosphorus fertilization treatments and tillage (moldboard vs. no-till) on weeds (density, biomass, and composition) before and after herbicide applications in 2016/corn and 2017/soybean. The second objective was to evaluate the effect of the same treatments 6 yr after no postemergence weed management in 2022/corn. Since the last evaluation performed in 2004, weed density, richness, and diversity increased, and more annual grasses were observed under both tillage regimes. No fertilization effect was observed on any weed variables, including composition, except for increased biomass when left to grow all season after crop planting. In managed plots, the density and biomass of annuals and perennials were generally higher in no-till, and discrepancies were highest for annual grass densities before herbicide application. Weed species richness and diversity based on counts were equivalent between tillage regimes, but total biomass was distributed between more species in no-till. Higher weed densities and concurrent weed biomass, observed in no-till, reduced crop yields in 2016/soybean only. The combination of low crop diversity and low use of residual herbicides during the trial potentially led to the observed species shifts and increased weed density.

Critical Period of Weed Control in Maize as Influenced by Soil Tillage Practices and Glyphosate Application

Increasing evidence on environmental and economic benefits has raised farmers’ interest in adopting alternative, less intensive soil management practices. To evaluate the influence of weed-competitive ability in response to a different tillage regime, a field study was conducted in maize under humid Central European climatic conditions in Slovenia. This study was established as a split-plot arrangement with three tillage practices (TPs) as the main plot: conventional (CN), conservation (CS), and no tillage (NT); this was combined with glyphosate application and the weed removal timing as the subplot. The weed removal timings were at the V3, V6, V9, V15, and R1 maize stages, with weed-free and weed season-long monitoring. The beginning and the end of the critical period of weed control (CPWC), based on a 5% maize yield loss rate, were determined by fitting the four-parameter log-logistic equations to the relative maize dry grain yield. The weed dry biomass from maize germination until the R1 growth stage in the NT TP was consistently lower than that in the CN and CS TP. Moreover, the NT TP resulted in a shorter CPWC (39 days after emergence (DAE)) compared to the CN (57 DAE) and CS (58 DAE). The results of CTWR (critical timing of weed removal) showed that less intensive tillage operations in the CS resulted in an earlier need for weed control (V2 and 23 DAE) compared to the CN (V3 and 39 DAE) and NT (V3 and 40 DAE). Our study suggests that the intensive tillage operations performed in the CN TP and the pre-sowing use of non-selective burndown herbicide in the NT delay the CTWR by more than 2 weeks, thus reducing the need for early post-emergence herbicide application in maize.

Influences of conservation tillage on soil macrofaunal biodiversity and trophic structure in the Mollisol region of Northeast China

Tillage regimes directly impact soil disturbance and crop residue levels in the field, subsequently affecting soil macrofauna abundance and diversity, crucial for maintaining soil health and ecosystem functionality. The present study aimed to investigate the effects of different tillage regimes (no-tillage (NT), conventional tillage (CT) and reduced-tillage (RT)) on soil properties and macrofaunal communities in a typical black soil region of Northeast China. Our study revealed that, in comparison to CT and RT, NT significantly enhanced soil macrofauna biodiversity and brought about modification in the community composition. Additionally, it reduced changes in the soil physical–chemical properties. Furthermore, the choice of tillage regimes impacted the trophic structure of soil macrofauna, manifesting in great density and species richness of herbivores and predators in NT plots with crop residue retention when compared to those managed with tillage. Overall, soil organic carbon (SOC) and pH played pivotal roles in regulating the soil macrofaunal community. The alternations observed in the soil macrofaunal community represented a comprehensive response to tillage practices and residue return, which in turn influenced soil properties and microenvironments, including food resources and microhabitats. Therefore, our findings indicated that conservation tillage exerted a notable influence on the soil macrofaunal community. This underscores the significance of soil environments and properties in molding the structure and composition of the soil macrofaunal community. The study will enhance comprehension of soil management practices and advocate for diversity within soil macrofaunal communities.

Semi-arid soil bacterial communities are refined by altered plant selection pressure under conservation management practices

Plants' ability to select for, and refine, their microbiome over time is well known. In soil, the strength of plant selection pressure on microbial composition can result in distinct rhizosphere, and root-zone communities, but may be masked in soils with lower native diversity such as semi-arid soils. Semi-arid soils are also known for their high potential for wind erosion, which may be mitigated by the implementation of cover crops. These cover crops may also alter the microbial composition of the semi-arid soils, but the strength of this effect, and the resulting changes in the composition of the microbiome, are less well known. This study aimed to address whether the implementation of a single-species wheat cover crop in semi-arid agricultural soils would impact the bacterial composition of the cash crop. We investigated three tillage regimes—no-tillage with a winter wheat cover crop, no-tillage winter fallow, and conventional tillage winter fallow—to determine the effects of tillage removal, and cover crop implementation on the soil bacterial community present in the root zone of the cash crop. It was determined that the composition of the bacterial microbiome was similar between cover cropped and non-cover cropped treatments. The similarity of bacterial composition was likely due to the strong effect of environmental selection reducing overall biodiversity in these soils. However, the variability of bacterial community composition was strongly reduced for the cover cropped treatment compared to the two non-cover cropped treatments. The similarity of bacterial communities with cover cropping, without significant soil physicochemical changes, suggests that plant-selection pressure, rather than management-induced changes in soil physicochemical properties, drove the refinement (decreased dissimilarity compared to non-cover cropped treatments) of the bacterial community. The composition of this refined community under cover cropping was determined to contain an enrichment of several genera of interest including N cycling and potential plant-growth promoting bacteria. In summary, the introduction of cover cropping in the nutrient and microbial-poor soil of the semi-arid Southern High Plains strongly refined the bacterial community and selected for organisms with the potential to improve soil functions associated with greater agronomic sustainability.

STRUCTURAL-AGGREGATE COMPOSITION AND SOIL WATER RESISTANCE BASED ON TILLAGE REGIMES IN SOUTHEAST KAZAKHSTAN

The promotion and rational development of drylands employed two tillage regimes (plowing to 20–22 cm and no-till) during the spring wheat and barley cultivation in Southeast Kazakhstan. The results established that the no-till scheme contributed to forming an excellent aggregate state of the arable soil layer for spring wheat and barley (65%–69%). The water-resistant aggregates were the highest with no-tillage (19.3%–21.8%), indicating the unsatisfactory water resistance of the soil structure. Enhancing the water-resistant aggregates requires using organic fertilizers to improve the establishment of perennial grasses, green manuring, and cover crops. No-till system inclined to boost the optimal soil density from a loose and slightly compact state of 1.19–1.23 g/cm3 to a dense 1.32–1.39 g/cm3. According to crop cultivar and tillage methods, the spring wheat and barley grain yield varied between 2.84 and 3.89 t/ha. High grain yield came from the spring barley cultivar Symbat. Spring showed promising performance when the plowing level was 20–22 cm and inferior only by 0.25 and 0.15 t/ha with no-till. Based on the two-factor analysis of variance, the cultivar contribution to the spring wheat and barley grain yield buildup depended on the shares of crop season of the research (year – environment) (40.9%–62.2%) and the tillage regimes (22.4%–32.2%). The grain yield formation was more dependent on the studied crops and their cultivars, and the dependence increased over the crop seasons due to weather conditions during the crop period.

DIFFERENT TILLAGE REGIMES' EFFECT ON SOIL-WATER PHYSICAL AND AGROCHEMICAL PROPERTIES UNDER THE ENVIRONMENTAL CONDITIONS OF SOUTH EAST KAZAKHSTAN

For improvement and rational use of rainfed lands, a study on the influence of different tillage methods proceeded on the soil-water physical relationship and soil agrochemical properties in Southeast Kazakhstan. In the arable soil layer (0–30 cm), the soil density during the studied crop’s life from sowing to harvesting, enhanced to a medium compacted state with the traditional method of tillage (1.28–1.29 g/cm3), slightly higher with the minimum tillage (1.30–1.31 g/cm3), and the highest with zero tillage (1.32–1.33 g/cm3). Tillage with better crumbling, dissolution, and superior ingestion of plant vestiges in the cultivated soil layer contributed to a slight decrease in soil density, both with traditional and minimum tillage regimes. Given the least rainfall in summer, there was a decline in the productive moisture reserves in the soil with customary tillage (15.9–34.5 mm). However, the soil moisture enhanced gradually with reduced tillage, i.e., minimal tillage (20.7–36.7 mm) and zero tillage (29.8–54.8 mm). The nitrate nitrogen content in the soil also decreased from the initial state to the cultivated crops’ harvest, and a significant decrease emerged with zero tillage. The prolonged rainless period, accompanied by a decline in relative air humidity, soil moisture, and temperature increases, affected plants’ physiological processes and, eventually, the studied crops’ yield. In the studied crops, on average, acquiring the highest yield of 1.76 t/ha was with minimal tillage. Based on two-way analysis of variance (ANOVA), the contributed share of the crops in the grain yield formation was according to crop season, ranging from 0.73% to 2.89%, and the soil cultivation methods’ share was 83.3%–93.8%. The grain yield formation has a greater dependence on the tillage regimes, although that reliance might vary in association with weather conditions during the crop life. In rainfed conditions of Southeast Kazakhstan, zero tillage results in a significant reduction in nitrate nitrogen compared with conventional and minimum tillage. Therefore, with no tillage, more nitrogen fertilizer is necessary than usual plowing and the application of potash fertilizers, regardless of tillage methods.

Water-stable aggregation among untilled and intensively tilled soils with similar contents of aggregating agents in central Ohio, USA

Organic carbon (OC), permanganate-oxidizable carbon (POXC), and autoclaved citrate-extractable (ACE) proteins are utilized as soil quality indicators due in part to their positive relationships with water-stable aggregation (WSA). Tillage-induced losses of WSA are oftentimes attributed to decreases in these soil constituents. The objective of the present study was to explain differences in WSA existing between tilled and untilled cropland soils through comparing the soils in terms of these and other aggregating agents. We examined WSA and a suite of related properties on conventional tillage (CT) and no-tillage (NT) soils of an Epiaqualf-Argiaquoll association along a low-relief hillslope in central Ohio, USA. Overall, WSA was strongly correlated (r > 0.7, P < 0.05) with OC, POXC, and ACE proteins, but when concentrations were similar between NT and CT soils for these constituents, most notably at the toeslope position, WSA was consistently greater for the NT soil. Statistically controlling for the effect of these individual WSA covariates did not change this result. Results suggest that heightened WSA for the NT vs. the CT soil may be due to the greater water repellency of the former when other aggregating agents are equivalent between tillage regimes. These findings suggest that soil quality evaluators should measure WSA directly rather than rely on inferences based on organic constituents, especially when working with CT soils from poorly drained, depositional landscape positions.

Soil Aggregation and Associated Organic Carbon and Total Nitrogen in a Sandy Loam Soil under Long-Term Tillage Effects

In Tunisia, climate change impacts that lead to the degradation of soil resources are considered to be a major limiting factor on socio-economic development. These impacts are exacerbated by the intensive plowing and cultivation practices used by Tunisian farmers, which expedite the depletion of soil organic matter (SOM), leading to changes in the physio-chemical properties of soil and consequently promoting soil erosion. In fact, the decrease in soil organic carbon (SOC) stocks affects soil’s fertility and the ability to regulate climate change. The objective of this study, which was conducted in Le Krib in the Siliana region of northwestern Tunisia, was to evaluate the effects of two cropping systems, consisting of durum wheat (Triticum aestivum) and oats (Avena sativa), and two types of tillage, no-till (NT) and mouldboard plowing (MP), on different soil aggregate classes (&gt;2000 µm, 2000–250 µm, 250–180 µm, 180–53 µm and &lt;53 µm) and soil physio-chemical properties, as well as the resulting effects on the carbon and nitrogen concentrations in these aggregates. The results showed that the carbon content of all soil aggregate classes was influenced by interactions between the previous crop and tillage regime. The clay-silt fraction had higher carbon concentrations under no-till and mouldboard plowing management. Furthermore, the previous crop and tillage type and their interactions had significant effects on nitrogen concentrations in micro-aggregates. The highest nitrogen concentrations (2846.6 ppm) were found in micro-aggregates in soils where the previous crop was durum wheat and mouldboard plowing was used, while the lowest concentrations (1297 ppm) were obtained in soils where the previous crop was oats and mouldboard plowing was used.

Effects of soil physical and chemical properties on phosphorus adsorption-desorption in fluvo-aquic soil under conservation tillage

Conservation tillage has been widely used in the North China Plain to improve the aggregate structure and promote soil organic matter (SOM) retention, which is closely associated with phosphorus (P) turnover. However, a quantitative description of how conservation tillage alters P adsorption and desorption characteristics via affecting soil physical and chemical properties remains lacking. Thus, we conducted a batch experiment using pilot soils that had experienced two tillage regimes (conventional/reduced tillage) and two types of straw management (straw returning/removal) for 13 years. The results indicated that the maximum adsorption capacity (Qm) and adsorption binding energy (KL) of reduced tillage decreased by 36.2% and 21.5%, respectively, and the average desorption rate (Dr) increased by 14.4% compared with conventional tillage. In addition, the Qm and KL of straw returning decreased by 40.5% and 51.9%, respectively, and the Dr increased by 25.2% compared with straw removal. The adsorption capacity of aggregates with different particle sizes showed the order of silt + clay > macroaggregate > / (≈) microaggregate, while the desorption capacity exhibited the opposite trend. Moreover, the Qm and KL depicted negative correlations with SOM, total P (TP), Olsen-P, and the mass proportion of macroaggregate. However, they exhibited positive correlations with free aluminum oxides (Ald), non-crystalline aluminum oxides (Alo), pH, specific surface area (SSA), and the mass proportion of microaggregate and silt + clay. The Dr was just the opposite with Qm and KL. The random forest results indicated that SOM, pH, SSA, TP, Ald, Olsen-P, and the mass proportion of macroaggregate were the key factors affecting the P adsorption and desorption. The physical and chemical properties collectively explained 80.8% of the total variance, and their interaction made the largest contribution. This study provides insights into how conservation tillage reduced P adsorption potential and promoted P desorption capacity from a physical and chemical perspective and emphasizes the importance of aggregate in the environmental behavior of P, which is of great importance for sustainable agricultural development and protecting food security.