Explore the vast range of titles available.

AimsTraditional tillage represents a serious threat to the stability of soil ecosystems. Understanding the response mechanisms of soil microbial community assembly to different tillage practices is a major topic of soil ecological research.MethodsHere, we investigated the bacterial community structures and assembly in bulk and rhizosphere soils of soybeans grown under traditional tillage (moldboard plow, MP) and two conservation tillage practices, namely, no-tillage (NT) and ridge tillage (RT), using high-throughput sequencing methods.ResultsCompared with MP, NT and RT increased the relative abundances of nitrifying bacteria of Nitrosospira sp. and the nitrogen-fixing bacteria of Mesorhizobium sp., Bradyrhizobium sp. and Burkholderia sp., but decreased the abundance of carbon-degrading bacteria, especially Blastococcus sp., Streptomyces sp. and Sphingomonas sp. The altered functional bacteria were mostly affiliated with biomarkers and keystone taxa in the NT and RT networks. For the results of network properties and assembly processes, we found that NT and RT habited a more stable bacterial network structure and a lower homogenizing dispersal value. Soil pH was the primary factor regulating both the bacterial community structures and assembly processes under the three tillage practices.ConclusionsThe soil bacterial community structures and assembly processes were profoundly altered by tillage practices. The changes in functional bacteria indicated that conservation tillage might contribute to soil carbon sequestration, while stimulating nitrogen fixation and nitrification.

Rice−wheat (Oryza sativa L.−Triticum aestivum L.) rotation is the major production system in Asia, covering about 18 million ha. Conventional practice of growing rice (puddled transplanting) and wheat (conventional till, CT) deteriorate soil physical properties, and are input- and energy-intensive. Zero-tillage (ZT) along with drill-seeding have been promoted to overcome these problems. A 7-yr permanent plot study evaluated various tillage and crop establishment (CE) methods on soil physical properties with an aim to improve soil health and resource-use efficiency. Treatments included transplanting and direct-seeding of rice on flat and raised beds with or without tillage followed by wheat in CT and ZT soil. Bulk density (Db) of the 10- to 20-cm soil layer was highest under puddled treatments (1.74-1.77 Mg m-3) and lowest under ZT treatments (1.66-1.71 Mg m-3). Likewise, soil penetration resistance (SPR) was highest at the 20-cm depth in puddled treatments (3.46-3.72 MPa) and lowest in ZT treatments (2.51-2.82 MPa). Compared with conventional practice, on average, water-stable aggregates (WSAs) > 0.25 mm were 28% higher in ZT direct-seeding with positive time trend of 4.02% yr-1. Infiltration was higher (0.29-0.40 cm h-1) in ZT treatments than puddled treatments (0.18 cm h-1). The least-limiting water range was about double in ZT direct-seeding than that of conventional practice. Gradual improvement in soil physical parameters in ZT system resulted in improvement in wheat yield and is expected to be superior in long-run on system (rice+wheat) basis. Further research is needed to understand mechanisms and requirements of two cereals with contrasting edaphic requirements in their new environment of ZT direct-seeding.

We have measured total soil organic carbon (SOC), dissolved organic carbon (DOC), and microbial lipid contents (as indices of microbial biomass and community structure), and their distributions to 60 cm depth in soils from replicated medium-term (2003-2008) experimental arable plots subject to different tillage regimes in Scotland. The treatments were zero tillage (ZT), minimum tillage (MT; cultivation to 7 cm), the conventional tillage (CT) practice of ploughing to 20 cm, and deep ploughing (DP) to 40 cm depth. In the 0-30 cm depth range, SOC content (corrected for bulk density differences between tillage treatments) was greatest under ZT and MT, but over 0-60 cm depth the SOC contents of these treatments were similar to the CT and DP treatments. DOC concentrations declined with increasing depth in ZT and MT above 20 cm, but there were no significant differences with depth in the CT and DP treatments. Beneath 20 cm, there was little change in DOC concentration with depth for all treatments, although for the MT treatment, there was less DOC beneath the depth of cultivation. The total microbial biomass decreased with increasing depth over the 0-60 cm range in the ZT and MT treatments, whereas it decreased with depth only below 30-40 cm in the CT and DP treatments. The microbial biomass was significantly different only between 0-5 cm in the ZT, CT and DP treatments, but not for other depths between all treatments. The bacterial biomass was greater in the ZT treatment than in MT, CT and DP near the soil surface, but not significantly different over the whole profile (0-60 cm). The fungal biomass decreased with depth in the ZT and MT treatments over the whole 0-60 cm depth range, whereas it decreased with depth only below 20 cm in the CT and DP treatments.

The combination of conservation tillage (non-inversion and no-till) with organic farming is rare due to weed problems. However, both practices have the potential to improve soil quality and increase soil organic C (SOC). This study investigated the changes in SOC, microbial biomass, and microbial composition during the transition from conventional to organic farming (from 2014 to 2020) in a long-term tillage trial established in 1999. Non-inversion minimum tillage to a depth of 10 cm (MT) resulted in SOC stratification, whilst conventional soil tillage with 25-cm-deep mouldboard ploughing (CT) maintained an even SOC distribution in the plough layer. After 12 years of contrasting tillage in 2011, the uppermost soil layer under MT had a 10% higher SOC content (1.6% w/w) than CT (1.45% w/w). This difference became even more pronounced after introducing organic farming in 2014. By the fall of 2020, the SOC content under MT increased to 1.94%, whilst it decreased slightly to 1.36% under CT, resulting in a 43% difference between the two systems. Conversion to organic farming increased microbial biomass under both tillage systems, whilst SOC remained unchanged in CT. Abundances of total bacterial and Crenarchaeal 16S rRNA and fungal ITS genes indicated shifts in the microbial community in response to tillage and depth. Fungal communities under MT were more responsive to organic farming than bacterial communities. The improved soil quality observed under MT supports its adoption in both organic and conventional systems, but potentially large yield losses due to increased weed cover discourage farmers from combining MT and organic farming.

Little information is available about their influences of conservation tillage on the distribution and storage of soil organic C (SOC) and total N in soil profiles in the North China Plain. We investigated the changes in SOC and total N as related to the shift from conventional to conservation tillage using a long-term field experiment with a winter wheat (Triticum aestivum L.)–corn (Zea mays L.) double cropping system. The experiment included four tillage treatments for winter wheat: moldboard plow without corn residue return (MP–R), moldboard plow with corn residue return (MP+R), rotary tillage (RT), and no-till (NT). Compared with the MP–R treatment, returning crop residue to the soil (MP+R, RT, and NT) increased SOC and total N in the 0- to 30-cm soil layer, but no distinct changes in SOC and total N concentration were observed among the four treatments at soil depths >30 cm. Compared with the MP+R treatment, the RT and NT treatments increased SOC and total N concentration significantly in the 0- to 10-cm layer but decreased SOC and total N concentration in the 10- to 20-cm layers. As a consequence, soil profile SOC and total N storage did not vary among the MP+R, RT, and NT treatments. Thus under the experimental conditions, conservation tillage (RT and NT) increased SOC and total N contents in the upper soil layers, but did not increase SOC and total N storage over conventional tillage (MP+R) in the soil profile.

A field study was carried out to analyze the short-term (2 years) effect of tillage and crop rotation on microbial community structure and enzyme activities of a clay loam soil. The experimental design was a split-plot arrangement of treatments, consisting of two tillage treatments—ridge tillage (RT) and no-tillage (NT)—in combination with two crop rotation treatments—corn (Zea mays L.) monoculture and a 2-year corn-soybean (Glycine max L.) rotation. Phospholipid fatty acid (PLFA) profiles were used to assess soil microbial community structure. No-tillage resulted in significantly higher total PLFAs compared to the RT treatment, which was accompanied by higher activities of protease, β-glucosaminidase, and β-glucosidase. This suggests a close link between soil microbial communities and enzyme activities in response to tillage. The increase of total microbial lipid biomass in the NT soils was due to the increase in both fungal and bacterial PLFAs. Crop rotation had little effect on soil bacterial communities and enzyme activities, but it significantly influenced soil fungal communities, particularly arbuscular mycorrhizal fungi. Soils under monoculture corn had higher fungal biomass than soils under corn-soybean rotation regardless of tillage treatment.

Tillage is among the most important soil management practices, which exert strong impacts on weed flora composition in different cropping systems. The large-scale adoption of tillage and cropping systems warrants thorough investigation regarding their impacts on weed flora composition. Therefore, this study was aimed to assess weed flora composition of various barley-based cropping systems (BBCSs) under different tillage practices (TPs). Barley was sown in fallow-barley (F-B), maize-barley (M-B), cotton-barley (C-B), mungbean-barley (Mu-B) and sorghum-barley (S-B) cropping systems with zero tillage (ZT), conventional tillage (CT), minimum tillage (MT), strip tillage (ST) and CT with bed sowing (CTBS). Significant differences (p < 0.05) were recorded among study years and interactions among BBCSs and TPs. The C-B system with ST during 1st year recorded the highest density (35 m− 2) of broadleaved weeds, whereas the highest density (37.76 m− 2) of broadleaved weeds was noted for the same cropping system with MT. All TPs, except BS resulted in increased density of broadleaved weeds in 2nd year compared with 1st year of the study, whereas BS reduced broadleaved weeds’ density during 2nd year. Nonetheless, M-B cropping system with ST and S-B cropping system with CTBS recorded the lowest density of broadleaved weeds during 1st and 2nd year, respectively. Similarly, C-B cropping system with ZT (39.33 m− 2) and MT (24.00 m− 2) recorded the lowest density of grassy weeds during 1st and 2nd year respectively. Nonetheless, S-B system with CTBS and S-B and Mu-B systems with ST recorded no grassy weeds during 1st and 2nd year, respectively. The S-B and M-B cropping systems suppressed various broadleaved and grassy weed species due to their allelopathic potential. In conclusion, different BBCSs had varying weed flora composition under different TPs. Adapting ST and CTBS can lower weed infestation. Similarly, inclusion of sorghum in rotation could be a viable option for effective weed management of barley-based cropping systems. Moreover, long-term experiments are needed to infer the weed seed bank in different TPs and BBCSs.

Human efforts to produce more food for increasing populations leave marks on the environment. The use of conventional agricultural practices, including intensive tillage based on the removal of crop residue, has magnified soil erosion and soil degradation. In recent years, the progressive increase in the concentration of greenhouse gases (GHGs) has created global interest in identifying different sustainable strategies in order to reduce their concentration in the atmosphere. Carbon stored in soil is 2–4 times higher than that stored in the atmosphere and four times more when compared to carbon stored in the vegetation. The process of carbon sequestration (CS) involves transferring CO2 from the atmosphere into the soil or storage of other forms of carbon to either defer or mitigate global warming and avoid dangerous climate change. The present review discusses the potential of soils in sequestering carbon and mitigating the accelerated greenhouse effects by adopting different agricultural management practices. A significant amount of soil organic carbon (SOC) could be sequestered by conversion of conventional tillage to conservation tillage. The most important aspect of conservation agriculture is thought to improve plant growth and soil health without damaging the environment. In the processes of climate change mitigation and adaptation, zero tillage has been found to be the most eco-friendly method among different tillage techniques. No-till practice is considered to enable sustainable cropping intensification to meet future agricultural demands. Although no-tillage suggests merely the absence of tillage, in reality, several components need to be applied to a conservation agriculture system to guarantee higher or equal yields and better environmental performance than conventional tillage systems.

The rice-wheat cropping system occupying 13.5 million ha is important to meet the challenge of food security in the Indo-Gangetic Plains. The consequences of current production practices viz., degraded soil health, high cost of cultivation, inefficient use of resources and environment raises the danger to its sustainability. In the Indo-Gangetic Plains (IGP) of South Asia, the most widely adopted resource conserving technology has been zero-tillage (ZT) in wheat after rice, particularly in India. The severity of system constraints can be reduced by ZT wheat via earlier/timely planting (5-10% yield gains), control of Phalaris minor, reduced cultivation costs (fuel saving of 36-43 litres ha-1 and higher returns of Rs 4300-5700 ha-1) and water saving. Soil organic carbon, porosity, aggregate size and infiltration rate also increased significantly with long term zero tillage. The yield increase alongwith a cost saving led to pretty robust adoption rate but still knowledge gaps exist. Therefore, more research is needed to understand the interactions between ZT and soil type, seasonal factors and cumulative effects that cause farmers to adhere to conventional tillage (CT) or reduced tillage (RT) in some plots or seasons. Therefore for further wider adoption, ZT should be considered as a system and be looked more precisely to suit varying farm situation.

Background and aims Conservation tillage enhances soil aggregate function, —a key factor for promoting soil nutrient cycling and plant growth. However, there is a limited understanding of how tillage practices impact soil nutrients, enzymes and microbes distribution among different-sized aggregates, and their potential subsequent effects on other soil functions and processes. Methods We conducted a long-term experiment involving maize ( Zea mays L.) cultivation in a semiarid farming region in Northwest China. Four tillages were implemented: no-tillage, minimal tillage, fold-tillage, and sub-tillage. Soil aggregates were categorized based on size: <0.25 mm (‘micro’), 0.25–2 mm (‘small’), and > 2 mm (‘macro’). We measured the nutrient contents, enzyme activity, enzymatic stoichiometry, and soil microbial community structure with each fraction, and assessed crop productivity. Results The no-tillage treatment increased soil C content, microbial biomass, and P and N availability within micro-aggregates and bulk soil. It also enhanced enzymatic activity related to C and P acquisition and the C: N enzymatic ratio but decreased the N: P enzymatic ratio in micro-aggregates. Notably, no-tillage promoted straw and root biomass and crop yield compared to conventional tillage. Microbial community structure differed under the different tillage regimes and among aggregate size fractions, particularly under conventional tillage, but the tillage system did not affect alpha diversity. Conclusions Our results highlight that long-term conservation tillage positively influenced soil aggregates by increasing carbon content and enzyme activity, thereby, reshaping the soil microbial community composition within aggregate size fractions in semiarid agroecosystems.