Conservation Tillage Management Research Articles

The LTAR Integrated Common Experiment at Southern Plains.

The Southern Plains (SP) is one of 18 Long-Term Agroecosystem Research network sites that combine strategic research projects with common measurements across multiple agroecosystems. Projects at the SP site focus on the use of indicator measurements to aid in assessment of land and nutrient management's impact on soil health, water quality, carbon and water balances, and forage biomass-quality in diversified, adaptive crop-livestock systems designed to overcome shifts in natural resources and climate. The prevailing treatment is tilled winter wheat (Triticum aestivum L.) that is grazed, hayed, harvested for grain, or grazed and harvested for grain. The alternative treatment is year-round annual cover crop forage mixes for cattle (Bos taurus) production planted in fall and spring under conservation tillage management. The area is subject to variable weather and climatic shifts that reduce the potential to diversify forage crops and limit grazing in southern tall grass prairies and small grain systems. Incorporation of fertilized, rain-fed, annual cool and warm season mixtures of cover crops could fill forage gaps. The presence of year-round ground cover reduces sediment and nutrient loading to surface waters while enhancing soil health and water holding capacity. Tools to aid agricultural producers and land and water resource managers have been developed and implemented to determine how climate, topography, and varying conservation management practices alter hydrological structures, greenhouse gas emissions, water usage, and soil resources.

The impact of arable soil management on physical functions – The ratio of air capacity and air permeability or hydraulic conductivity as a document of harmful soil compaction

Soil health or soil degradation criteria are until now not well documented for a greater number of soil profiles under conventional and conservation tillage management in the literature. In order to evaluate the compaction status of more than 700 arable sites analyzed within the last 40 years, the Compaction Verification Tool (CVT) was applied according to Zink et al. (2011). Besides the ratio of air capacity (AC, at a matric potential of −6 kPa) and saturated hydraulic conductivity (Ks), the ratio of AC and air conductivity (Ka, at a matric potential of −6 kPa) was considered for evaluating the compaction status with respect to potentially harmful soil alterations. The compaction status was classified into the CVT classes I–IV, where a harmful subsoil compaction was assumed, if both values of AC and Ks or AC and Ka simultaneously exceeded (are smaller than) their defined critical value indicating limited conditions for plant growth (CVT class IV). We analyzed the compaction status of soil profiles with respect to clay content, soil type, structural stage (aggregate forms) and time span of sampling (1980–1999, 2000–2020) under conventional and conservation tillage for top- and subsoil horizons. While also some of the annually plowed topsoils under conventional tillage showed critical values of AC, Ks and Ka, the occurrence of harmful soil compaction is most dominant in the subsoil horizons (> 30 cm depth) because of a higher proportion of class IV which increased with the clay content (from < 12 % to > 12 % clay), irrespective of the applied ratio used for verification (AC/Ks or AC/Ka). Especially the highly productive Luvisols showed a high percentage of harmful compaction in the subsoil (30–41 % in CVT class IV). Soil profiles under conservation tillage management are less affected by harmful compaction. The more aggregated subsoils showed smaller proportions of class IV, which was further influenced by the clay content.

Response of Soil Moisture to Four Rainfall Regimes and Tillage Measures under Natural Rainfall in Red Soil Region, Southern China

Investigating the effects of natural rainfall on the soil moisture for sloping farmland is extremely important for comprehending a variety of hydrological processes. Rainfall regimes can elicit different responses to soil moisture at the depth of soil layers, and the responses may differ depending on the landscape position of the sloping farmland. This paper utilized the surface runoff natural rainfall and soil moisture measured on sloping farmland with conventional tillage and contour tillage in the red soil area of China to investigate the influence of natural rainfall events on soil moisture content and to evaluate if the response results were consistent across the four rainfall regimes. Natural rainfall events were classified into different four regimes in line with rainfall duration, rainfall amount, and the maximum 30 min rainfall intensity (I30) by the k-means clustering method, including advanced, intermediate, uniform and delayed regimes. The result showed that the advanced regime was the predominant one in the study area, which represented 45.9% of the total rainfall events. The rainfall regimes influenced the surface runoff coefficient and runoff depth on sloping farmland for conventional and contour tillage, with the uniform regime generating the highest runoff coefficient (5.20% and 5.82%) and runoff depth (2.00% and 2.05%), respectively. For the conventional tillage, soil moisture at a depth of 0–20 cm increased appreciably when the rainfall amount was larger than 20 mm and larger than 30 mm for the advanced regime. For the contour tillage, soil moisture in 20–40 cm layer increased for the advanced regime when the rainfall amount was larger than 15 mm and 30 mm, while the values were modified with rainfall duration and the antecedent dry day (ADD). A longer rainfall duration had a more obvious effect on soil moisture increasing in deep soil. At a depth of 20 cm, the ADD showed an appreciably positive correlation with the increment in soil moisture, which means that a brief ADD produces a compounding effect for a natural rainfall event. The present results underline the complexity of the effect of the rainfall events on soil moisture under two tillage measures for different rainfall regimes and suggest that the advanced regime significantly affects the distinction of soil moisture and the contour tillage can effectively reduce soil water loss and enhance water storage on the sloping farmland with red soil, presenting a theoretical basis for local soil and water conservation research and sloping farmland conservation tillage management.

Short‐term conservation tillage degrades soil infiltration properties in the black soil region of Northeast China

AbstractSoil infiltration properties (SIPs) are crucial soil hydraulic parameters for hydrological and erosion models as they regulate the movement of water and nutrients within the soil. Tillage practice can significantly impact the hydrological and erosional processes of sloping farmland by changing SIPs through altering soil structure. Nevertheless, knowledge regarding the effects of short‐term conservation tillage on SIPs is unclear, which greatly limits the management of soil and water resources of sloping farmland. This study aimed to clarify the potential impact and underlying mechanisms of short‐term implementation of conservation tillage on SIPs under three typical tillage management types: conventional downslope tillage (DT), conservation contour tillage (CT), and no‐tillage (NT) in the black soil region of Northeast China. SIPs of initial infiltration rate (IIR), steady infiltration (SIR), and hydraulic conductivity (Ks) were determined by a field disc infiltration experiment under pressure heads (h) of −3, −1.5, and 0 cm. The results revealed that short‐term implementation of conservation tillage management degraded SIPs, with a significant difference observed between DT and NT. In comparison to DT, the mean SIPs of IIR, SIR, and Ks of CT decreased by 27.5%, 31.2%, and 28.6%, and the corresponding reduced values of NT were 54.1%, 65.0%, and 65.5%, respectively. SIPs were significantly correlated with soil texture, bulk density (BD), capillary porosity (CP), total porosity (TP), field capacity (FC), saturated water content (SSWC), and organic matter content (SOM). Among these influencing factors, the variations in SIPs among different tillage management and soil layers were primarily influenced by differences in clay and gravel contents, FC, and SSWC and SSWC played the most critical role. These results highlight the substantial impacts and clarify the mechanisms of short‐term conservation tillage on SIPs, which is helpful for understanding the potential effect of short‐term conservation tillage management on hydrology and erosional processes, thereby improving the sustainable utilization of arable land.

Effect of long-term conservation tillage management on microbial diversity under Mediterranean rainfed conditions

Conservation Agriculture has been the subject of numerous studies for decades. However, its impact on the soil microbial community has often been overlooked. Recent studies have shed light on the changes in soil bacterial composition resulting from modifications in tillage practices, particularly when compared to conventional tillage methods. However, there is a lack of soil microbial community analysis conducted under conservation tillage and rainfed conditions in the Mediterranean basin. A metataxonomic approach was employed to assess the influence of 19 years (2004–2022) of minimum tillage (MT) and no-till (NT) practices, along with crop rotation, on the soil bacterial community at upper layers (15 cm depth). This field study involved three different seasonal moments throughout the year. Results revealed that both sampling time and tillage management significantly influenced the structure of the bacterial community, whereas no effect was observed due to the crop. May showed a higher taxonomic diversity than July and December, showing differences in some o fthe most abundant phyla, such as Actinobacteria, Firmicutes and Proteobacteria. On the other hand, the long-term application of NT was found to lead to a significant decrease in bacterial diversity, with lower abundances of the phyla Chloroflexi, Gemmatimonadetes, and Armatimonadota, as well as an increase in k-strategist bacteria compared to MT. However, no significant effect on alpha diversity was observed as a result of tillage. no variations in phyla composition were observed attributable to crop, as the primary distinctions were identified among legume crops, which were associated with different sampling times. Therefore, our conclusion is that over this period, NT did not promote microbial diversity in the upper soil layers, despite notable shifts in bacterial composition occurring across seasonal time points in both tillage management systems.

Residue Management and Nutrient Dynamics in Conservation Agriculture: A Review

Conservation tillage significantly influence the physico-chemical properties of soil that makes microclimate conducive for crop growth and productivity. The use of chemical fertilizers alone to sustain high crop yield has not been successful due to its effects on soil acidity, nutrient leaching, degradation of soil’s physical properties and organic matter. Higher levels of soil organic carbon, microbial biomass of carbon and nitrogen, nitrogen mineralization, total nitrogen and extractable phosphorus are directly related to crop residues under conservation tillage management. Conservation agriculture (minimum or no tillage with residue retention and crop rotation) practices has potential for increasing the nutrient supply to crops through changes in the mineralization and immobilization of nutrients by microbial biomass and provide an eco-protective environment for sustainable production. Conservation agriculture reduces nutrient percolation/leaching from the soil profile, can redistribute the soil profiles thus affects nutrient supply, and its storage. Entire soil-plant continuum changes after the conversion from conventional agriculture to conservation agriculture. The review therefore highlights the nutrient dynamics under crop residue management with no or minimum tillage.

Long-term warming increased microbial carbon use efficiency and turnover rate under conservation tillage system

Microbial carbon use efficiency (CUE), a combination of respiration and growth, plays a central role in the flow of carbon through soil. Carbon-depleted agricultural soils are promoted as a global sink for atmospheric carbon in a warming climate. There is an urgent need to understand whether increased soil respiration from warmed cropland soils reduces CUE, potentially creating positive feedback to atmospheric CO2 concentrations. We investigated microbial CUE and turnover rates in response to experimental warming in topsoils under traditional tillage and conservation tillage management using a substrate-independent H218O labeling method. Eleven years of warming increased soil organic carbon (SOC) by 3.9% in topsoil under conservation tillage, while there was no change in traditional tilled soils. Soil microbial respiration was increased by 108% and 11.6% under traditional tillage and conservation tillage, respectively. Warming decreased microbial growth by 60.3% in traditional tilled topsoils, but increased it by 50.8% under conservation tillage. Therefore, CUE and microbial turnover rates decreased by 77% and 22.2%, respectively, in response to warming in traditional tilled topsoils and increased by 29.1% and 19.3%, respectively, under conservation tillage. Soil hydrolase (β-glucosidase, cellobiohydrolase and N-acetyl-glucosaminidase) activities were increased by warming under both management types, but oxidase (peroxidase and phenol oxidase) activities only increased in traditional tilled topsoils. Hydrolase:oxidase ratios were 4.1 times less in warmed traditional tilled soils compared to unwarmed traditional tilled soils but were 0.63 times more in warmed conservation tillage soils compared with unwarmed conservation tillage soils. Microbial CUE was positively correlated with dissolved organic carbon (DOC), DOC:SOC and hydrolase:oxidase, suggesting that substrate quality and availability were important factors driving changes in microbial physiology. The SOC increased with microbial growth, CUE and turnover rate. Our findings suggest that microorganisms in warmed topsoils under conservation tillage use a greater abundance of high-quality substrates more efficiently to build biomass, thereby reducing the positive feedback effect of increased soil respiration caused by soil warming.

Simulated Cropping Season Effects on N Mineralization from Accumulated No-Till Crop Residues

The adoption of no-till management practices has increased in the United States over the last decade. In the state of North Dakota, approximately 5.7 million hectares of cropland is managed under no-till or conservation tillage management practices. Even though conservation tillage is known for building soil health, increasing soil organic matter, capturing soil moisture, and reducing wind and water erosion, it also presents a unique best management practice since an increased mass of crop residue remains on the soil surface. Producers are concerned about whether plant needs are being met by nitrogen fertilizer that is currently being applied based on current North Dakota recommendations for long-term no-till systems. A Forman clay loam soil (fine-loamy, mixed, superactive, frigid Calcic Argiudolls) was used in this study, as it represented glacial till soils of the region. We examined whether N mineralization from surface-applied crop residue would result in similar or different results when compared to crop residue mixed into the soil. Soil freeze-thaw contribution to soil N mineralization was also evaluated. Six residue treatments with different C/N ratios including corn (Zea mays L.), soybean (Glycine max L.), forage radish (Raphanus sativus L.), winter pea (Pisum sativum L.), spring wheat (Triticum aestivum L.), and winter wheat (Triticum aestivum L.) were used. Five 10–14-week cycles with a three-week freeze period between each cycle at 0 ºC were evaluated for NO3-N production. Crop residues with a narrow C/N ratio contributed to greater instances of N mineralization during each incubation cycle, and the accumulation of crop residues with a wide C/N ratio over each incubation cycle following the first incubation did not offset the immobilization trends observed in the first incubation. A change in N mineralized in the untreated control soil during the last two incubation cycles may have been caused by freeze-thaw effects or a shift in microbial population due to a lack of fresh C inputs.

Response of Fungal Sub-Communities in a Maize-Wheat Rotation Field Subjected to Long-Term Conservation Tillage Management.

Conservation tillage is an advanced agricultural technology that seeks to minimize soil disturbance by reducing, or even eliminating tillage. Straw or stubble mulching in conservation tillage systems help to increase crop yield, maintain biodiversity and increase levels of exogenous nutrients, all of which may influence the structure of fungal communities in the soil. Currently, however, the assembly processes and co-occurrence patterns of fungal sub-communities remain unknown. In this paper, we investigated the effects of no-tillage and straw mulching on the composition, assembly process, and co-occurrence patterns of soil fungal sub-communities in a long-term experimental plot (15 years). The results revealed that combine straw mulching with no-tillage significantly increased the richness of fungi but not their diversity. Differential abundance analysis and principal component analysis (PCA) indicated that tillage management had a greater effect on the fungal communities of abundant and intermediate taxa than on the rare taxa. Available phosphorus (AP) and total nitrogen (TN) were the major determinants of fungal sub-communities in NT treatment. The abundant fungal sub-communities were assembled by deterministic processes under medium strength selection, while strong conservation tillage strength shifts the abundant sub-community assembly process from deterministic to stochastic. Overall, the investigation of the ecological network indicated that no-tillage and straw mulching practices decreased the complexity of the abundant and intermediate fungal networks, while not significantly influencing rare fungal networks. These findings refine our knowledge of the response of fungal sub-communities to conservation tillage management techniques and provide new insights into understanding fungal sub-community assembly.

Continuous cropping legumes in semi-arid Southern Africa: Legume productivity and soil health implications

Abstract Legume agronomic research in Southern Africa has often focused on integrating legumes into smallholder cereal cropping systems, but there is limited information available on the feasibility and soil health implications of continuous cropping legumes in the region. Continuous legumes may be suitable in areas with large livestock populations where a premium is placed on high-quality forage, or where efforts are underway to reclaim degraded cropland. Our objectives in this study were to (i) evaluate the performance of diverse legumes under continuous cropping and conservation tillage management with no fertility inputs and (ii) assess the response of soil health parameters to continuous legumes in a semi-arid environment. A 4-year study was conducted in Limpopo, South Africa beginning in the 2011–2012 growing season in which 10 legume and fallow treatments were imposed in the same plots for 4 growing seasons. All legumes responded negatively in varying degrees to continuous cropping in terms of biomass and nutrient accumulation. Lablab (Lablab purpureus L.) was the top-performing legume in the study and accumulated 4.5–13 Mg ha−1 of biomass and 153–345, 11–34, and 75–286 kg ha−1 of N, P, and K, respectively. Lablab often outperformed natural fallow, while other legumes generally performed as well as or inferior to natural fallow, depending on species and growing season. Cowpea (Vigna unguiculata Walp) was especially incompatible with continuous cropping and averaged less than 252 kg ha−1 and 2.1 Mg ha−1 of grain and biomass, respectively, from 2012–2013 to 2014–2015. Continuous cropping did not lead to sustained improvements in soil health. By 2014–2015, soil organic matter for all treatments had either declined or resembled baseline values. Rates of potentially mineralizable N in cowpea, lablab, vining mucuna (Mucuna pruriens var. Utilis), natural fallow, and bare ground plots fell by 70–96% during the study. There was also evidence for lower recovery of leached K by legumes compared to natural fallow species. In conclusion, legumes, such as lablab, should be considered as continuous forages on marginal land in areas where high-quality forage is in demand, but continuous cropping legumes without fertility inputs are not an effective strategy for improving soil health on degraded cropland in this semi-arid region of Southern Africa. Future research efforts may focus on the grazing strategies and baling frequencies required to optimize annual biomass accumulation of continuous lablab to meet livestock demand and support smallholder livelihoods.

Conservation tillage methods affect soil water use and spring maize yield in a semi-humid drought-prone area of China

In the arid areas of Northwest China, water has become a key limiting factor for agricultural development, so conservation tillage management has become an important measure to improve water use efficiency and crop yield. Our experiment, conducted from 2015 to 2018, explored the effects of conventional flat planting with no mulch (NP), with straw mulch (SM), and with plastic mulch (PM); and also ridge and furrow planting without mulch (RF) and ridge-furrow planting with plastic film and straw mulch (RFPFM) on soil nutrients, soil water storage, water use efficiency, and crop yield when compared with traditional no mulch and no fertilization cultivation (CK). Four years of experiments showed that compared to CK, SM and RFPFM had significantly increased soil surface nutrient content and increased organic matter content, and the water depletion during the maize growth period of the NP, SM, PM, RF, and RFPFM treatments increased by 9.7%, 0.6%, 8.6%, 4.4%, and 14.2%, respectively. For four years, the average spring maize yields of the NP, SM, PM, RF, and RFPFM treatments increased by 36%, 87%, 115%, 40%, and 119%, compared to those of CK. The PM and RFPFM treatments' water use efficiencies were significantly different from those of the other treatments and the basic decreasing trend of water use efficiency was RFPFM > PM > SM > RF > NP > CK. In summary, we showed that because ridge-furrow planting with plastic film mulch improved both soil nutrients and crop yields, it is a preferred cultivation method for agricultural water utilization in arid areas.

Long‐term organic management combined with conservation tillage enhanced soil organic carbon accumulation and aggregation

AbstractSuccessful synergy between organic management and conservation tillage could provide the best agroecological benefits by minimizing the negative effects of both synthetic chemicals and intensive tillage on soils. We studied the long‐term impacts of conventional and organic crop management under different tillage regimes on soil organic C (SOC) and soil aggregation, leveraging Rodale Institute's long‐term Farming Systems Trial. The experiment was initiated in 1981 with three cropping systems under intensive tillage management: (a) conventional (3‐yr rotation of corn–corn–soybean) with synthetic fertilizer application, (b) organic–legume (4‐yr rotation of corn–oats–soybean/wheat–wheat) organic system with legume as sole N source, and (c) organic–manure (8‐yr rotation of soybean/wheat–wheat/hay–hay–hay–corn silage/wheat–wheat–corn–oats) organic system with composted manure and legumes as N sources. There were eight replications for each of these cropping systems when the trial was initiated in 1981. In 2008, four replicates of each cropping system treatment were placed under conservation tillage management. Soils were collected from 0 to 10‐, 10 to 20‐, and 20 to 30‐cm depths in 2018 and measured for total SOC, active SOC fractions (microbial biomass C, water extractable C, permanganate‐oxidizable C), aggregate size distribution, and wet aggregate stability. Overall, total and active SOC increased by 16–132% under organic management compared with conventional management and the increase was more pronounced under organic–manure treatment than organic–legume treatment. Results also showed that 10 yr of tillage treatments did not influence active and total SOC concentrations, but influenced dry aggregate size distribution and wet aggregate stability. This study suggests that in long‐term organic cropping systems, incorporated composted manure and perennial hay vs. legumes alone accumulated the greatest amount of SOC compared with conventional systems. Conservation tillage in organic systems improved aggregation; however, beyond 10 yr, it is necessary to reflect tillage effects on SOC.

Soil health assessment after 40 years of conservation and conventional tillage management in Southeastern Coastal Plain soils

AbstractConservation tillage (CST) and cover crops are important components of soil health management. In the present study, we applied two independent soil health assessment approaches to evaluate the impacts of 40‐yr CST and additional 4‐yr cover cropping on a range of soil health indicators and the overall soil health in typical southeastern Coastal Plain soils. Soils were collected at 0–15 cm and analyzed for physical, chemical, and biological indicators. The Soil Management Assessment Framework (SMAF) and Cornell's Comprehensive Assessment of Soil Health (CASH) were used to calculate soil health indices. When compared to conventional tillage, 40‐yr CST increased active carbon (C) from 301 to 420 mg kg–1 and organic nitrogen (N) mineralization potentials from 0.78 to 0.91 mg kg–1 d–1, but it reduced soil electrical conductivity from 133 to 101 μs cm–1. No difference in soil aggregate stability, total C, extractable phosphorous and potassium, microbial biomass C, respiration, and glucosidase activities were observed between the two tillage treatments. Cover cropping had no impacts on any measured variables, except that it increased soil total N. Regardless of tillage and cover cropping, both the SMAF and CASH scoring functions suggested no changes in overall soil health. Soil organic C (SOC) was the only indicator positively correlated with both the SMAF and CASH indices, indicating its importance in maintaining the health of the tested soils. Moreover, CASH index recommended improving soil structure and SOC as the management priority to maintain or improve the overall soil health. Increasing organic inputs along with CST is seemingly the optimal management option.

Peanut nitrogen credits to winter wheat are negligible under conservation tillage management in the southeastern USA

Agricultural extension services in many peanut (Arachis hypogaea L.)-producing regions recommend that farmers reduce nitrogen (N) fertilization rates, or apply N credits, to crops planted after peanut but do not typically specify how peanut residue management or planting schedules of subsequent crops affect the magnitude of peanut N credits. The objective of this study was to quantify peanut N credits to winter wheat (Triticum aestivum L.) in a conservation tillage cropping system in different subtropical growing environments. A five site-year study was conducted in Florida, USA beginning in 2016. A split-plot experimental design was arranged in which summer crop [peanut, cotton (Gossypium hirsutum L.), and weed-free fallow] was the main plot factor, while N rate (0, 34, 67, and 101 kg N ha−1) to winter wheat was the split plot factor. Peanut and cotton were planted under strip-tillage, while winter wheat was drilled into peanut and cotton residues and weed-free fallow plots without tillage. Although peanut residues accumulated 54–93 kg N ha−1, plant available N at winter wheat planting in the 0–15 cm soil depth range of former peanut plots was only higher than in former cotton or fallow plots for one site-year. A previous peanut crop did not affect winter wheat grain yield, but there were cases of lower grain yield, grain N removal, and agronomic efficiency following cotton relative to peanut depending on site. Nonlinear regression procedures predicted that N rates required to optimize grain yields following peanut would exceed 94 kg N ha−1, further indicating the absence of detectible peanut N credits in this study. These results suggest that assuming peanut provides N credits to subsequent crops in the southeastern USA is not justified and, if assumed, will reduce the productivity of subsequent crops.

Can conservation tillage and residue management enhance energy use efficiency and sustainability of rice-pea system in the Eastern Himalayas?

ABSTRACTLow productivity and energy use efficiency (EUE) of rice farming are the major concerns for agricultural sustainability in the Eastern Himalayan region of India. A field experiment on rice (Oryza sativa L.)-pea (Pisum sativum L) system was conducted for three consecutive years during 2012–15 in lowland ecosystem to assess the direct and residual impact of tillage and residue management (RM) practises on productivity and sustainability. Significantly higher grain yield of rice was achieved under no-till (NT) than minimum tillage (MT) and conventional tillage (CT). Among RM practises, 50% NPK + green leaf manure, 50% NPK + weed biomass and 50% NPK + in-situ residue retention recorded significantly higher mean grain yields than application of 50% NPK and 100% NPK without residues. Residual effect of MT in preceding rice gave significantly higher green pod yield of succeeding pea than NT and CT. The system EUE was significantly higher under MT (rice)-NT (pea) compared to those of NT-NT and CT-NT systems. The sustainable yield index of rice and pea was maximum under MT-NT followed by NT-NT. Thus, NT/MT with suitable RM practises is a pertinent strategy for sustainable productivity of rice-pea system in the Eastern Himalayas and in similar adjoining regions.

Grazing Crop Residues Has Less Impact in the Short‐Term on Soil Properties than Baling in the Central Great Plains

Core Ideas Corn residue grazing had little to no impact on soil health indicators. Residue baling increased wind erosion risks by 22 to 56%. Baling reduced near‐surface soil water content by 8 to 32%. Soil type or precipitation amount did not influence residue removal impacts on soil properties. Residue grazing can be a more sustainable practice than baling Cattle grazing and baling of corn (Zea mays L.) residues are common practices in integrated crop–livestock systems, but their impacts on soil properties are not well understood on a regional scale. We conducted a 3‐yr study across a precipitation gradient (ranging from 400 to 804 mm) in the central Great Plains to evaluate soil compaction, structural quality, water content, fertility, sorptivity, and microbial biomass in response to corn residue grazing and baling. Six on‐farm sites varying in soil texture, organic matter, crop rotation, and irrigation practices were established with three residue treatments: control, grazing, and baling. Sites were predominantly under conservation tillage management. Residue baling reduced residue cover by 57% and residue grazing by 17% relative to the control. At most sites, residue baling reduced near‐surface soil water content by 8 to 32% and increased wind erodible fraction by 22 to 56% compared with the control but grazing generally had no effect. Residue grazing and baling had small or no negative effects on other measured soil properties regardless of soil type or precipitation amount. When changes in soil properties did occur, they were due to differences in grazing duration or agronomic management. For example, grazing during spring at one of the sites increased soil bulk density by 7% (1.17 vs. 1.26 Mg m−3) relative to the control. This short‐term study indicates that residue grazing, in general, does not impact soil properties, but residue baling at high rates (&gt;50%) could increase wind erosion risks and reduce surface soil water content in this region.

Stimulation of N2O emission by conservation tillage management in agricultural lands: A meta-analysis

Conservation tillage has been widely adopted in agricultural lands worldwide and is considered a potential strategy for climate change mitigation through enhanced carbon sequestration. However, conservation tillage may alter soil N2O emissions, which may diminish the potential climate change mitigation benefits. Based on 212 observations from 40 publications, a meta-analysis was conducted to quantitatively assess the effects of climate regimes, initial soil properties, and type/duration of agricultural practices on soil N2O emission following application of conservation tillage. Overall, conservation tillage significantly increased soil N2O emission by 17.8% compared to conventional tillage. The greatest increase in N2O emission was observed from soils in tropical climates (70.1%) experiencing short-term (29.3%) application of conservation tillage. Soil pH and clay content significantly influenced N2O emission, while overall soil texture and soil organic carbon (SOC) were not effective predictors of soil N2O emission following conservation tillage. According to the categorical meta-analysis, agricultural practices, including water, residue, and rotation managements and crop types, significantly affected soil N2O emission following conservation tillage. Conservation tillage induced N2O emissions were mitigated with rain-fed cropping systems, residue removal, crop rotation and cultivation of beans and some vegetables. Significant categorical variables affecting N2O emission were mainly attributed to soil aeration and substrate availability, which were important factors affecting nitrification and denitrification processes. Overall, the conservation tillage induced N2O emission factor (EFad) increased by 0.40%, suggesting an attenuation of climate change benefits from increased N2O emission. Our meta-analysis provides a scientific basis for assessing the effects of conservation tillage on N2O emissions and provides site-specific information to mitigate N2O emissions associated with conservation tillage practices.

Tillage and residue retention effect on crop and water productivity of Indian mustard (Brassica juncea) under rainfed conditions

A field experiment was conducted during rabi season of 2014-15 and 2015-16 to study the effect of moisture conservation techniques and tillage management practices on growth, productivity and economics of Indian mustard[Brassica juncea (L.) Czernj and Coss.]. The experiment was laid out in split-plot design with three replications in cropping system mode. The main plot treatments consisted of four moisture conservation practices adopted inkharif season cropviz. ridges and furrows (RF), RF + crop residue (CR) 4 tonnes/ha, RF + CR 2 tonnes/ha + vesicular arbuscular mycorrhiza (VAM) and flat sowing (FS) and in sub plots;five zero tillage management techniques, viz. zero tillage (ZT), ZT + seed priming, ZT + CR 4 tonnes/ha, ZT + CR 2 tonnes/ha + Hydrogel and conventional tillage (CT) were executed in mustard. Results revealed that moisture conservation technique,RF + CR 4 tonnes/ha in main plot and tillage management practice ZT + CR 4 tonnes/ha in sub plot recorded significantly superior growth parameters, physiological indices, yield attributes and yield values over rest of the treatments. Sowing in furrows under RF + CR 4 tonnes/ha recorded highest values for seeds/siliqua and siliqua length to the tune of 13.16 and 4.17 cm, seed yield (2.12 tonnes/ha) and stover yield (7.46 tonnes/ha), respectively. Furthermore under RF +CR 4 tonnes/ha treatment registered significantly higherWUE (21.63 kg/ha/mm) as well as maximumN, P and K uptake values of 102.7, 21.02 and 97.15 kg/ha, respectively. Highest net returns of ` 54100/ha as well as B:C ratio (2.88) were obtained under RF + CR 4 tonnes/ha. In sub-plots, ZT + CR 4 tonnes/ha gave significantly higher values of siliquae/plant, seeds/siliqua and siliqua length to the tune of 342, 13.18 and 4.05 cm, respectively. ZT + CR 4 tonnes/ha recorded maximum seed yield (2.05 tonnes/ha) closely followed by ZT + CR 2 tonnes/ha + Hydrogel (1.94 tonnes/ha) and both the treatments were statistically at par. Water use efficiency under ZT sowing with CR 4 tonnes/ha and ZT + CR 2 tonnes/ha + Hydrogel, gave statistically at par values of 20.93 and 19.72 kg/ha/mm, respectively. In spite of higher cost of cultivation, significantly maximum net returns (` 49500/ha) were obtained under ZT + CR 4 tonnes/ha. Thus on the basis research findings, it can be established that under rainfed conditions after kharif crop harvest planting of Indian mustard can be done in left over furrows without any tillage with application of ex-situ CR 4 tonnes/ha or with CR 2 tonnes/ha + Hydrogel to save time, reduce cost and capitalize of residual moisture.

Weed dynamics in conservation agricultural systems as influenced by conservation tillage and nutrient management practices under rainfed finger millet

Weeds are major threats for loss of yield in any cropping system. Especially in conservation tillage systems, it is a basic necessary requirement to keep the weed population below their threshold levels to realize optimum grain yields. Managing weeds in conservation tillage systems are very essential to optimize crop production. Hence, to study the effect of conservation tillage practices on weed dynamics, soil weed seed bank and their distribution, a field experiment was conducted under rainfed finger millet (Eleusine coracana (L.) Gaertn.) on Alfisols for two consecutive seasons during 2014 and 2015 at All India Coordinated Research Project on Dryland Agriculture, University of Agricultural Sciences, GKVK, Bengaluru, India under split-plot design with three main plots (different tillages) and five sub-plots (different nutrient management). Conventional tillage has recorded significantly higher grain and straw yield of finger millet (3.04 and 4.69 t/ha, respectively) due to effective control of weeds as evidenced by lower total weed density and dry weight observed (13.7 no./m2, 8.0 g/m2 at 30 DAS and 23.9 no./m2, 9.0 g/m2 at 60 DAS) along with higher weed control efficiency (92.5–93.2% in 2014 and 93.3–93.8% in 2015) and lower weed index (7.6–10.3%) due to lower number of weed seeds observed during 2014 (12.3, 19.5 and 4.6/kg soil at 15, 30 and 60 days, respectively) and 2015 (11.3, 17.6 and 4.1/kg soil at 15, 30 and 60 days, respectively as compared to minimum tillage (2.60 and 4.03 t/ha, respectively). Whereas, zero tillage has recorded significantly lower grain and straw yield (2.09 and 3.24 t/ha, respectively) due to poor weed control as observed by higher soil weed seed bank. Among different nutrient management practices application of 100% recommended NPK + 7.5 t FYM/ha yielded significantly higher grain and straw yields (3.03 and 4.68 t/ha, respectively) over other nutrient management practices. Wherein, the soil weed seed bank was not significantly influenced by nutrient management practices and their interactions with the tillage.

Splash erosion in maize crops under conservation management in combination with shallow strip-tillage before sowing

Soil under maize cropping is among the most endangered by erosion. The effect of conservation tillage management on values of splash erosion when using shallow strip tillage before sowing maize was evaluated in the Central Bohemian region (Czech Republic) during the period 2010–2012. The following types of tillage management using conventional technology and shallow tillage were evaluated: ploughed plots with mulch formed by weed biomass (PL&lt;sub&gt;W&lt;/sub&gt;), ploughed plots with mulch from perennial ryegrass plants (PL&lt;sub&gt;PR&lt;/sub&gt;), ploughed plots without mulch (PL) and shallow tillage (ST) where the mulch was formed by cereals straw. Furthermore, values of the splash erosion, plants and plant residues coverage ratio of soil by image analysis and the stability of soil aggregates were monitored during the whole experiment. The average value of splash erosion (MSR) was higher by 18.7% in the variant of PL&lt;sub&gt;W&lt;/sub&gt;, lower by 35.9% in PL&lt;sub&gt;PR&lt;/sub&gt;, and lower by 39.5% in ST, than in the control treatment PL (MSR value for PL = 100%) for the whole evaluated period (2010–2012). The average values of the soil surface plant coverage ratio in the plots with mulch ranged from 1.5 to 43.0% at the beginning of the vegetation period, and from 4.9 to 85.5% in the second half of the vegetation period. A positive correlation was observed between the average values of the stability of soil aggregates and the plant coverage ratio of the soil surface in 2010 and 2011.