Subsoiling Research Articles

How Does Sustainable Management Practices Affect Weed Flora and Tuber Yield of Potato Crop in Mediterranean Environment?

AbstractIntensive potato cultivation affects weed species composition by selecting dominant and competitive weeds that represent a constraint of potato productivity. Field experiments were conducted during 2015 and 2016 growing seasons to examine the effects of soil tillage (plowing (PL), spading (SM), sub soiling (SS)) and fertilizer source (mineral (Min) and organic (Org)) on potato yield and weed community under Mediterranean environment. A randomized complete block design with three replications was adopted. Weed density and biomass were measured at the potato harvesting time. Weed density was highest in SS, intermediate in SM, and lowest in PL (43.8, 40.3, and 28.8 plants m−2). Similar trend was observed in weed biomass. Weed density and biomass were higher in Org than Min (42.1 vs. 36.4 plants m−2 and 129.6 vs. 117.9 g m−2, respectively). Perennial, monocot, and dicot weed species were the most abundant in subsoiling (13.1, 9.3 and 34.5 plants m−2). Density of perennial and dicot species were higher in Org than Min. Monocots were mostly linked with Min, while dicots were mainly associated with Org. Although tuber yield was higher in PL and Min (481.9 and 627.5 g m−2 of DM), it was affected by growing season and might be associated to SM and Org. Although the study shows that increased weed biodiversity in the system, achieved with more sustainable practices, proves to be an obstacle to potato production, the adoption of spading machine applied in combination with mineral and organic fertilizers could be a valid alternative to plowing. Further studies are required to develop sustainable agricultural techniques able to improve the competitive capacity of crops and reduce the selection of dominant weed species.

Effects of conservation practices on rainfed maize yield, furrow water infiltration, and soil moisture for surface sealing loam soils in the Yazoo‐Mississippi Delta

AbstractDecades of intense tillage have created the problem of surface sealing in loam soils across the Mid‐South United States and beyond. These soils exhibit low organic matter, poor aggregate stability, and ultimately low infiltration rates that decrease rainfed crop productivity and increase irrigation water demand. This research quantified the effects of soil management practices on rainfed maize (Zea mays L.) yield, furrow water infiltration, and soil moisture in Commerce very fine sandy loam and silt loam near Stoneville, MS. The six treatments included conventional tillage (CT), cereal rye (CR; Secale cereale L.), furrow diking (FD), no‐till (NT), polyacrylamide (PAM), and subsoiling (SS). No other treatment achieved a significantly higher maize grain yield than the CT control treatment in both years consistently. Single‐ring infiltrometer results indicated no significant differences among CT, CR, PAM, and SS in 2022 and between CT and NT in 2021. Neutron attenuation found that total soil water within the top 1 m was not significantly different among CT, FD, and SS on any of the eight measurement dates throughout the 2022 maize reproductive period. However, soil moisture was numerically lower for FD in the late reproductive stages. These findings suggest that environmental factors and other agronomic operations may counteract conservation practices, limiting their effectiveness at reducing irrigation requirements to mitigate groundwater depletion in the Mississippi River Valley Alluvial Aquifer.

The effect of tillage methods on soil physical properties and maize yield in Eastern Inner Mongolia

Long-term shallow tillage has degraded the soil structure, which has increased the difficulty of increasing the yield of maize (Zea mays L.) in Eastern Inner Mongolia. The aim of this study was to select optimal tillage practices to gain high maize yield in this region. The experiment included farm shallow rotary tillage (FR), strip cultivation (SC), subsoiling (SS), deep ploughing (DP) and no-tillage (NT) in maize fields in Chifeng, Tongliao, Xingan and Hulun Buir, Eastern Inner Mongolia. The effects of tillage practices on soil physical properties and maize yield were studied from 2018 to 2020. The results showed that bulk densities of SC, SS and DP were all lower than that of FR at each site. In contrast, the soil aeration porosity was higher from SC, SS and DP compared with FR at some soil depths. The water contents of DP and SS at Tongliao and Xingan and no-tillage (NT) at Hulun Buir were higher than that of FR. Correlation analysis showed favorable soil conditions promoted maize grain yield. The yields of maize that used SC and DP were 4.3% and 10.96% significantly higher in Chifeng, respectively, while the yields in Xingan were 15.93% and 18.22% significantly higher than those of FR, respectively. SS and DP resulted in a higher yield in Tongliao, and the other tillage methods had a higher yield in Hulun Buir compared with FR, whereas, the yield of NT was less than that of FR in Chifeng and Tongliao. Based on the physical properties of the soil and yield of maize, SC and DP are the optimal tillage practice for Chifeng and Xingan; SS and DP are optimal for Tongliao and Hulun Buir.

Effects of tillage management on cbbL-carrying bacteria and soil organic carbon dynamics across aggregate size classes in the farmland of North China Plain

Calvin-Benson-Bassham cycle (cbbL)-carrying bacteria in soil are essential to renew and circulate organic matter. However, the relation between cbbL-carrying bacteria and soil carbon dynamics under tillage managements, especially across the aggregate size remains unclear. Thus, in our study, soil organic carbon (SOC) storages, mineralization, and the cbbL-carrying bacterial community across five soil aggregate sizes were thoroughly investigated under four tillage treatments: conventional rotary tillage (CT), deep plowing (DP), subsoiling (SS), no-tillage (NT). We found macroaggregates (>2 mm) contributed most with regard to SOC stocks, whereas microaggregates (<0.25 mm) contributed the least among all the tillage managements (NT, DP, SS and CT). Macroaggregates (>1 mm) with the highest cumulative SOC mineralization were found in subsoiling, whereas microaggregates had the lowest cumulative mineralization under no-tillage. By physically protecting, no-tillage specifically inhibited carbon dioxide (CO2) emissions in macroaggregates (>1 mm), whereas increased SOC levels and encouraged CO2 releases across microaggregates. Shifts in the co-occurrence network demonstrated that subsoiling promoted the joint symbiotic function between cbbL-carrying bacteria, the efficiency of matter and energy, and information transfer. And the keystone species, the enhanced cooperation and stochastic processes of autotrophic microorganisms under subsoiling lead to increased carbon fixation and reduced CO2 emissions in microaggregates with limited oxygen and nutrients. Overall, our work verified physical protection of large aggregates under no-tillage and improvement of microbial interaction efficiency under subsoiling. This may offer a theoretical foundation for the choice of tillage practices in fluvo-aquic soil regions.

Effects of five years conservation tillage for hedging against drought, stabilizing maize yield, and improving soil environment in the drylands of northern China.

Continuous tillage cultivation positioning trials can provide the basis for maintaining soil health, improving resource utilization efficiency and crop productivity, and achieving sustainable agricultural development. In this study, changes in soil stability and water-holding capacity characteristics were measured under different tillage cultivations from a multi-year microscopic perspective and analyzed to evaluate selected key indicators. Continuous monitoring of rainfall utilization efficiency and yield was carried out for five years. Here, we discuss the role of conservation tillage in buffering and stabilizing rainfall precipitation pattern on the fluctuation and uncertainty of soil water retention and water supply capacity and soil quality. The study was carried out on dryland areas of the Loess Plateau in northern China with eight tillage systems established in 2016: no-tillage (NT); no-tillage and straw (NTS); subsoiling (SU); subsoiling and straw (SUS); rotary tillage (RT); rotary tillage and straw (RTS); conventional tillage (CT); and conventional tillage and straw (CTS). All treatments were applied in conjunction with continuous cropping for five years. The evaluated soil parameters were mean weight diameter (MWD), geometric mean diameter (GMD), >0.25 mm aggregate content (R0.25) of water-stable aggregates (WSAs), soil moisture characteristic curve (SMCC), specific soil water capacity (Cθ), soil organic matter (SOM), rainfall utilization efficiency (RUE), and maize yields for five consecutive years. The MWD, GMD, and R0.25 of SUS were 27.38%, 17.57%, and 7.68% more than CTS (control), respectively. Overall, SOM, average annual RUE, and average annual yields increased by 14.64%, 11.89%, and 9.59%, respectively, compared with 2016. Our results strongly suggest that conservation tillage can considerably improve these characterization indicators. SUS was more effective than CTS in the 0-40 cm soil layer at hedging against drought in the area, stabilizing crop production, and achieving sustainable agricultural development.

Subsoiling reduces CO2 concentrations in soil profile of winter wheat – summer maize rotation ecosystem in the North China Plain: a strategy to achieve carbon neutrality in farmland

ABSTRACT Reducing CO2 emissions from agricultural soils is a key component of the overall carbon reduction strategy. The closed chamber method was used to continuously monitor CO2 concentration in soil profiles of winter wheat-summer maize rotation fields in the North China Plain (NCP) during 2015–2017. Additionally, we evaluated the contribution of different tillage methods (Rotary tillage (RT), Subsoiling (SS), No- tillage (ZT), and conventional tillage (CT) in combination with Straw return (s) and straw removal (0)) to reducing soil CO2 emission. The results showed that the concentration of CO2 increased with the soil depth and peaked at the 150 cm layer. The trend of CO2 concentration in soil profiles under different tillage treatments was CTS > RTS > ZTS > SSS, and the average concentration in maize season was higher than that in wheat season. In addition, soil moisture and temperature in the 0–10 cm soil layer were significantly correlated with soil CO2 concentrations. Thus, our results highlight that the SSs plays a critical role in moderating soil CO2 emissions. This process merits further study to effectively regulate soil CO2 release and achieve carbon neutrality with less carbon emissions in farmland ecosystems.

An In Situ Videotaping Approach for Parameterizing Subsoiling-Induced Soil Disturbance

Subsoiling (SS) is an important technology in conservation tillage, but soil-disturbance characteristics in the SS are rarely described. Research on soil-disturbance characteristics during SS is conducive to the design and optimization of subsoilers, which provides a basis for reducing draft force and energy consumption. This study conducted SS experiments at five different tillage depths in the field with a specific field in situ test-rig facility, and in situ videotaping was made from five positions during SS. The microrelief test, draft force test, disturbance cross-section test and disturbance process analysis were conducted after SS. The results showed that draft force increased with tillage depth as a quadratic function. Soil displacement parameters and soil crack parameters extracted from the video of SS were significantly correlated with tillage depth, which could be used for a quantitative description of the paddy soil-disturbance characteristics. Cross-sectional area showed a trend of “increasing then decreasing” with increasing tillage depth, reaching a maximum at a tillage depth of 20 cm. When the tillage depth was greater than 20 cm, the bottom of the disturbing boundary formed a “mole cavity”. Fallback rate was used to describe the change in disturbed height or width during and after SS, which exceeded 100% at maximum. The surface roughness of microrelief and the size of the average clods reached the maximum at tillage depth of 20 cm. Considering the shallow cultivation layer of paddy soil in rice–wheat rotation, the recommended tillage depth of 20 cm could achieve maximum soil disturbance and minimum energy consumed.

Interactions between Intrinsic Soil Properties and Deep Tillage in the Sustainable Management of Perennial Crops

Choosing the appropriate management system is essential for sustainable agricultural practices. Yet, soil-specific properties at the subsurface are seldom considered when choosing the appropriate tillage system. This study assessed the effect of tillage depth on physical–hydraulic properties in three contrasting soil classes in the establishment of perennial crops. Tillage practices were evaluated in soils with natural dense layers (Inceptisols and Ultisols), and soils with very small and stable granular structure (Oxisols). From least to most aggressive, tested tillage systems included surface furrowing + plant holes (MT); plowing followed by two diskings + furrowing (CT); plowing followed by two diskings + subsoiling (SB); and plowing followed by two diskings + rotary hoeing (DM). Physical indicators with the greatest explanatory power were relative field capacity (RFC, 97%), aeration capacity (AC, 95%), macroporosity (Pmac, 95%), the S index (Sgi, 89%), and bulk density (Bd, 81%). DM caused the greatest modification in soil structure, especially at the surface. It increased values of AC, Pmac, and Sgi, and reduced Bd values. Only deep tillage systems (DM and SB) improved soil structure in deeper layers. Highest Bd values were observed for MT (1.47 g cm−3), and lowest for DM (1.21 g cm−3). Soil classes responded differently to soil tillage systems. DM was most effective in soils with densified layers (Inceptisol and Ultisol). Effects were less expressive in the studied Oxisol. Comparing MT and DM, Pmac increased by more than 100% in the studied Ultisol, but by less than 20% in the Oxisol. No tillage system affected the Oxisol’s soil structure in deeper layers, due to its small and stable granular structure. The choice of optimal tillage strategies should consider soil-specific properties, especially at greater depths, to guarantee more productive and sustainable crop systems.

Evaluation of carbon mineralization and its temperature sensitivity in different soil aggregates and moisture regimes: A 21-year tillage experiment.

Characterizing soil organic carbon (SOC) mineralization and its temperature sensitivity (Q10) under different soil moisture in tillage systems is crucial for determining global carbon balance under climate warming and increasing precipitation. Aggregate protection can potentially govern SOC mineralization and its Q10. However, how tillage and aggregate sizes affect SOC mineralization and its Q10, especially under varying soil moisture, remains unclear. Soil samples (0-10 cm and 10-20 cm) were collected from a 21-year field study with four tillage treatments: conventional tillage (CT), reduced tillage (RT), no-tillage (NT), and subsoiling (SS). Bulk soil and dry-sieved aggregates were incubated at 15°C and 25°C at low, medium, and high moistures (i.e., 40%, 70%, and 100% water-holding capacity, respectively). Macro-aggregates (> 0.25 mm) had lower SOC mineralization relative to micro-aggregates (< 0.25 mm) across all soil temperatures, moistures, and depths (P < 0.01), which was attributed to their lower SOC quality (i.e., higher ratio of SOC to total nitrogen and lower ratio of dissolved organic carbon to SOC). Moreover, NT and SS promoted macro-aggregation relative to CT and RT, and thereby decreased mineralization (P < 0.001). However, Q10 was higher in macro-aggregates than in micro-aggregates at low and medium moistures. The Q10 was negatively correlated with the SOC quality in macro-aggregates (P < 0.05). The macroaggregate-associated SOC quality was lower under NT and SS than under CT and RT, which resulted in a greater Q10 under NT and SS at low and medium moistures, suggesting that NT and SS may accelerate SOC losses under global warming. Furthermore, increased soil moisture could lower Q10, and no differences among tillage practices were observed at high moisture levels (P > 0.05). Overall, our findings indicated that NT and SS decreased SOC mineralization but increased Q10 because of their large amounts of macro-aggregates with low SOC quality, and the improvement of Q10 was constrained by increasing soil moisture.

Carbon isotope discrimination and the factors affecting it in a summer maize field under different tillage systems.

Based on two years of field experiments, under different soil tillage methods and straw management practices, which included conventional tillage (CT), subsoiling (SS), rotary tillage (RT), and no-tillage (NT), combined with either straw return (S) or straw removal (0), we characterized the dynamic changes in Δ13C among three height layers [upper (U, 240 cm above the ground), middle (M, 120 cm above the ground), and lower (L, 30 cm above the ground)] of the summer maize canopy. The Δ13C, the factors affecting it, and the relationships between Δ13C and soil water content (SWC), the leaf area index (LAI), canopy microclimate, and the CO2 concentration were elucidated. The results indicated that the Δ13C of summer maize at the pre-filling stage was greater than that at the post-filling stage. Δ13C also varied at different heights, with the order of the Δ13C values being L > U > M. Among the different tillage methods, the Δ13C values were ordered SSS > CTS > RTS > NTS. SSS and NTS significantly increased the LAI; air temperature and relative humidity tended to gradually decrease with the increase in height of summer maize. Correlation analyses of the various influencing factors and Δ13C showed that SWC, LAI, air temperature, and CO2 concentration were all positively correlated with Δ13C, in which LAI and air temperature were significantly or extremely significantly positively correlated with Δ13C. In addition, we show that Δ13C can be used as a prediction index for summer maize yield, providing a theoretical basis for future yield research that may save precious time in summer maize breeding efforts.

Improvement of soil aggregate-associated carbon sequestration capacity after 14 years of conservation tillage

Summary The North China Plain is an important summer maize/winter wheat rotation area. However, over the years, continued intensive tillage has destroyed the soil aggregate accelerating the mineralization and decomposition of soil organic carbon (SOC), which plays an important role in soil quality, as increased organic carbon storage improves soil fertility and crop yields. Thus, the objective of this study was to explore the comprehensive impact of tillage methods on soil aggregates, aggregate-associated SOC, and carbon sequestration capacity under a regime of straw return. In 2002, we started a 14-year long-term tillage experiment; then in 2016–2017, we tested the following tillage methods, zero tillage (ZT), rotary tillage (RT), subsoiling (SS), and conventional tillage (CT). The results showed that in the 0–10 cm soil layer, tillage methods significantly reduced the proportion of aggregates in the order of 2–0.25 &gt; 5–2 &gt; 0.25–0.053 mm. Additionally, conservation tillage (i.e., SS and ZT) significantly increased the percentage of macroaggregates (0–40 cm) and their SOC content, compared to CT. Additionally, the contribution rate of macroaggregates to SOC was 17.2% and 30.6% higher under SS and ZT than under CT, respectively. Conservation tillage methods improved the carbon sequestration capacity of soil aggregates. Our study provides a theoretical basis for the development of more suitable tillage methods. Furthermore, long-term conservation tillage seemingly protected large aggregates and, SOC, whereby carbon sequestration was enhanced and soil carbon emissions were effectively reduced.

Effects of fallow tillage on winter wheat yield and predictions under different precipitation types.

In northern China, precipitation that is primarily concentrated during the fallow period is insufficient for the growth stage, creates a moisture shortage, and leads to low, unstable yields. Yield prediction in the early growth stages significantly informs field management decisions for winter wheat (Triticum aestivum L.). A 10-year field experiment carried out in the Loess Plateau area tested how three tillage practices (deep ploughing (DP), subsoiling (SS), and no tillage (NT)) influenced cultivation and yield across different fallow periods. The experiment used the random forest (RF) algorithm to construct a prediction model of yields and yield components. Our results revealed that tillage during the fallow period was more effective than NT in improving yield in dryland wheat. Under drought condition, DP during the fallow period achieved a higher yield than SS, especially in drought years; DP was 16% higher than SS. RF was deemed fit for yield prediction across different precipitation years. An RF model was developed using meteorological factors for fixed variables and soil water storage after tillage during a fallow period for a control variable. Small error values existed in the prediction yield, spike number, and grains number per spike. Additionally, the relative error of crop yield under fallow tillage (5.24%) was smaller than that of NT (6.49%). The prediction error of relative meteorological yield was minimum and optimal, indicating that the model is suitable to explain the influence of meteorological factors on yield.

Increase in maize yield and soil aggregate-associated carbon in North China due to long-term conservation tillage

SummaryThe North China Plain (NCP) is an important agricultural area, where conventional tillage (CT) is used year-round. However, long-term CT has damaged the soil structure, threatening agricultural sustainability. Since 2002, we have conducted a long-term tillage experiment in the NCP to explore the effects of different types of tillage on soil and crop yield. As part of long-term conservation tillage, we conducted a 2-year study in 2016/2017 to determine the impact of no tillage (NT), subsoiling (SS), rotary tillage (RT) and CT on soil aggregate distribution, aggregate-associated organic carbon (AOC), aggregate-associated microbial biomass carbon (AMBC), and maize yield. Compared to CT, NT increased the content of macro-aggregates (+4.8%), aggregate-AOC (+8.3%), and aggregate-AMBC (+18.3%), but decreased maize yield (−11.5%). SS increased the contents of macro-aggregates (+5%), aggregate-AOC (+14.7%), and aggregate-AMBC (+16%); although the yield increase was not significant (+0.22%), it had the highest economic benefit among the four tillage measures. RT had no significant advantage when considering the above soil variables; moreover, it reduced maize yield by 16.1% compared with CT. Overall, SS is a suitable tillage measure to improve soil macro-aggregate content, carbon content, yield, and economic benefit in the NCP area.

Subsoiling Affecting Soil Quality Parameters and Sugarcane Yield in Multiratooning System in Subtropical India

ABSTRACT Soil compaction in the plow layer of soils is becoming a serious concern because of conventional tillage practices adopted by sugarcane growers utilizing a rotavator, particularly in medium to heavy textured soils. Continuous use of machinery causes compaction in the plow layer; thus strategic tillage practices have become an essential component in intensive agriculture. Keeping these points in view, a field experiment was conducted in split plot design considering four pre-plant tillage treatments, i.e., (i) one subsoiling (SS) followed by two harrowings (H) (ii) subsoiling alone and direct planting through Sugarcane Cutter Planter (SS) (iii) one plowing through moldboard (MB) plow and two harrowings (MB+H) (iv) and conventional practice (CP) in main plots and three ratoon management treatments viz., (i) HW:Three hand weedings (HW) (ii) integrated weed management (IWM), trash mulching at the time of ratoon initiation and application of microbial consortia (TM +MC) in subplots. Results on bulk density in surface and subsurface layers indicated a significant reduction due to subsoiling. Higher availability of N (252 to 310.2 kg ha−1) was analyzed with adoption of subsoiling as compared to conventional practice (218.4 to 224 kg N ha−1). Subsoiling improved soil microbial biomass carbon (SMBC) by 39% to 73% and 32.20% to 46% as compared to conventional practice in 0–15 cm and 15–30 cm depth, respectively. Among all the primary tillage treatments, sub soiling enhanced SMBC at the highest level (1574 mg C/kg soil/day in 0–15 cm soil depth). Sugarcane (97.26 t ha−1) and sugar (11.87 t ha−1) yields also improved significantly under subsoiling as compared to other pre-plant tillage treatments. Subsoiling before planting also increased mean ratoon cane (117.6 t ha−1) and sugar yields (14.48 t/ha). In addition to trash mulching and application of microbial consortia in ratoon crop proved effective for sustaining higher ratoon yields in sugarcane. Short title: Minimum tillage affecting soil quality parameters and sugarcane yield

Tillage and irrigation increase wheat root systems at deep soil layer and grain yields in lime concretion black soil

In lime concretion black soil, a two-factor (tillage and irrigation) split block experiment from 2015 to 2017 was conducted to identify whether their combination is suitable for the improvement of winter wheat yield and water use efficiency. The main treatments were subsoiling (SS) and rotary tillage (RT), with secondary treatments of three irrigation regimes: no irrigation during the whole growth period (W0), irrigation at jointing stage (W1), and irrigation at both jointing and anthesis stages (W2). In combination with a soil column experiment, the contribution of the root system in different soil layers to yield was clarified. The results indicated that both tillage and irrigation significantly influenced the spatiotemporal distributions of the root systems and yield components, while tillage produced the strongest effect. Compared with RT, SS significantly promoted the root penetration and delayed root senescence in deep soil layers. With increasing soil depth, each root configuration parameter (dry root weight density, DRWD; root length density, RLD; root surface area per unit area, RSA; root volume per unit area, RV) gradually decreased, and the peak appearance times of each root parameter in RT and three parameters (RLD, RSA and RV) in SS were postponed from heading to anthesis and from anthesis to filling stage, respectively. The average post-peak attenuation values at soil layers from 60 to 100 cm in W1 were less than those in W0 and W2. SSW1 generated the highest grain yields, with an average increase of 31.88% compared with the yield in RTW0. Root systems at three soil layers (0–40 cm, 40–80 cm and below 80 cm) differentially contributed to grain yields with 78.32%, 12.09% and 9.59%, respectively. The growth peak of the deep root system in SSW1 was postponed to the filling stage, and the post-peak attenuation declining rates were also slowed. Therefore, SSW1 is an effective cultivation method improving grain yields and water use efficiency in lime concretion black soil.

Evaluating soil physical quality indicators of a Vertisol as affected by different tillage practices under wheat-maize system in the North China Plain

Soil physical quality (SPQ) is an important parameter for crop growth. Tillage management is widely recognized to affect SPQ remarkably, but such an effect is complicated in Vertisols by shrinking and swelling soil structure. The objectives of this study were to (i) investigate how tillage practices affected SPQ as indicated by the S index, least limiting water range (LLWR) and water stress percentage (WSP); and (ii) determine the relationship between these SPQ indicators and crop yield. A 4-year field experiment, which was conducted in a Vertisol under wheat-maize rotation system in the North China Plain, consisted of four tillage treatments: no tillage (NT), rotary tillage (RT), subsoiling (SS), and deep ploughing (DP). Soil water retention curve (SWRC), soil shrinkage curve (SSC), penetration resistance (PR), and bulk density (BD) of the 0−10 and 10−20 cm layer were measured during wheat and maize seasons, and soil water content was continuously monitored in situ. The S index, LLWR and WSP were determined. Our results showed that SSCs were parallel to each other among four tillage treatments, indicating that tillage did not impact shrinkage capacity (P > 0.05). Relative to NT and RT treatments, the SS and DP treatments improved soil physical quality (higher S index and larger LLWR), particularly in the 10−20 cm layer. The S index presented a poor relation with wheat (P > 0.05) and maize yields (P > 0.05), while LLWR had a significant correlation with wheat yield (P < 0.05) but not with maize yield (P > 0.05). A new proposed SPQ indicator, WSP, is defined as the percentage of the period when the soil water content is above the field water capacity (waterlogging stress percentage, WLP) or below the wilting point (drought stress percentage, DSP) to the entire crop season period. The WLP presented a significantly negative relation with maize yield (P < 0.01) but not with wheat yield (P > 0.05), whereas the DSP had no relation with wheat and maize yield (P > 0.05). Moreover, the WSP was observed to be independent of the volume change in the Vertisol. Our results demonstrate that LLWR and WLP can be regarded as suitable indicators for evaluating SPQ in wheat and maize seasons, respectively, but the latter is more conveniently applied in a Vertisol.

Sugarcane Yield Using Minimum Tillage Technology Through Subsoiling: Beneficial Impact on Soil Compaction, Carbon Conservation and Activity of Soil Enzymes

Adverse effect of intensive tillage practices on soil chemical and biological properties is already known. Soil organic carbon maintains porosity, releases nutrients for crop growth and also provides shelters to microbes. However, maintaining soil organic carbon at higher level and increasing crop productivity have become two faces of a single coin. Without addressing both issues simultaneously, the sustainability of production system will be far away. Strategic tillage intervention in no-tillage plots for sustaining long-term productivity is gaining importance. Strategic tillage through subsoiling/ripping of soil up to 45 cm depth at about 1 m spacing before sugarcane planting is feasible in sugarcane-based system. Thus, keeping the above points in view, the experiment was conducted during 2015–2017 with hypotheses of (i) whether the minimum tillage (once subsoiling) could maintain soil physical, chemical and biological parameters to sustain sugarcane productivity for longer period and (ii) how the mouldboard ploughing and/or conventional tillage practice affects these parameters and crop yields. The experiment was laid out in four preplant tillage treatments, i.e., one subsoiling (SS) and two harrowings, minimum tillage through subsoiling and direct planting of sugarcane through IISR Cutter Planter (SS), one ploughing through mouldboard plough and two harrowings (MBP + H) and conventional practice (CP—two ploughings through cultivator and one through rotavator) with six replications in randomized block design. The effect of these treatments was recorded on various soil physical, chemical and biological parameters vis-a-vis infiltration rate, cumulative infiltration and optimizing sugarcane yield in subtropical India. The results concluded that minimum tillage and direct planting of sugarcane through Sugarcane Cutter Planter could break hard impervious layer and improve soil physical, chemical and biological parameters besides improving sugarcane and sugar yields. Minimum tillage favoured build-up of soil organic carbon (SOC) and also release of nutrients for crop growth, which optimized rhizospheric environment as compared to conventional practice. Minimum tillage through subsoiling had shown major effect in reducing soil compaction in subsurface layers (bulk density—1.52 Mg m−3 (SS) vs 1.61 Mg m−3 through MBP + H). During tillering period, basic infiltration rate could reach the level of 7.5 mm/hr in SS plots compared to 5.5 mm/hr in conventional practice (CP). Minimum tillage recorded the highest SOC at all the crop growth stages. The highest mean SOC was recorded during grand growth phase (13.51 Mg ha−1). Minimum tillage altered lower amount of soil and showed the highest population of soil bacteria (log10 6.90x 105). Thus, the minimum tillage through subsoiling significantly improved sugarcane (96.32 t ha−1) and sugar yields (12.14 t ha−1) as compared to conventional tillage/mouldboard ploughing.

Subsoiling Improves the Photosynthetic Characteristics of Leaves and Water Use Efficiency of Rainfed Summer Maize in the Southern Huang-Huai-Hai Plain of China

In the southern Huang-Huai-Hai (HHH) region, China, maize production is frequently threatened by waterlogging at the seedling stage and by drought at the big flare stage. A two-year field experiment was performed to explore whether subsoiling (SS) in the winter wheat season could improve the photosynthetic capacity and increase the water use efficiency (WUE) of summer maize using the variety, Luyu9105. A split design was adopted in the experiment. The main plots used tillage practices, including SS and rotary tillage (RT). The subplots consisted of two irrigation methods, i.e., applied supplemental irrigation at the big flare stage (I) and no irrigation at the big flare stage (NI). The results showed that the SS treatment significantly increased soil water content (SWC) in the 40–60 cm soil layer. The SS treatment improved green leaf area index (gLAI) by 15.1%–30.2%, and enhanced the ear-leaf net photosynthetic rate (Pn), stomatal conductance (gs), intercellular CO2 concentration (ci) and transpiration rate (Tr), and was accompanied by an increase in the grain-filling duration (T) by 5 days and the mean grain-filling rate (Va). The SS treatment decreased the stomatal limitation (Ls), indicating that RT treatment, which was under lower SWC, led to a decrease in Pn. Applied supplemental irrigation under RT treatment was able to compensate for the growth of leaves, but could not reverse the decreasing trend in the gLAI. Ultimately, the SS treatment improved WUE by 9.1%–9.9%, and increased grain yields by 10.0%–29.3%. Therefore, this study showed that in the southern Huang-Huai-Hai Plain, which has a yellow cinnamon soil type, the practice of SS can improve the photosynthetic characteristics of leaves and WUE of rainfed summer maize.

The regional water-conserving and yield-increasing characteristics and suitability of soil tillage practices in Northern China

Water deficiency seriously restricts the agricultural production in Northern China. Soil tillage practices can conserve water and increase yield effectively, but the regional applicability of soil tillage practices has not been systematically studied so far. It is significant to study the regional characteristics of tillage practices on water-conserving and yield-increasing so that the optimal practices for improving the crop water production and maintaining the agricultural sustainable development can be determined. This study applied the meta-analysis method to analyze results extracted from 156 peer-reviewed published papers conducted at 62 agricultural experimental sites for evaluating the effects of commonly used tillage practices, i.e., No-tillage (NT), Subsoiling (SS), Mulching (M), Ridge and Furrow Planting without Mulching (F), and Ridge and Furrow Planting with Mulching (F–M) on crop yield, water consumption and water use efficiency (WUE) of wheat and maize in Northern China. The results showed that NT only increased yield of winter wheat in North-central China and spring maize in Northeast China. SS increased wheat and maize yield by 16.3 ± 3.2 % and 9.2 ± 3.0 %, and increased water consumption by 8.4 ± 3.4 % and 1.8 ± 1.8 %, respectively. M increased the yield of wheat and maize by 14.9 ± 2.9 % and 17.7 ± 6.2 %, respectively, while it did not increase the water consumption. F increased the yield of wheat by 5.0 ± 1.1 %. F–M increased wheat and maize yield by 18.9 ± 6.3 % and 36.6 ± 11.8 %, respectively. This study recommends that, SS is suitable for winter wheat and summer maize in North-central China. M and F–M are suitable for spring maize in North-central China as well as wheat and maize in Northwest and Northeast China

Tillage system affects soil water and photosynthesis of plastic-mulched maize on the semiarid Loess Plateau of China

Water deficit is a threat to agricultural sustainability in the semiarid Loess Plateau of China due to low and variable precipitation. Technologies to improve soil water content (SWC) are necessary for sustainable intensification of maize production. The potential of plastic film mulch and reduced tillage to improve SWC has been reported for the Loess Plateau. However, there has been little research on how tillage management can be integrated with plastic mulching as an approach to improve SWC and maize photosynthesis. A 3-yr field study was conducted to investigate how tillage system influences SWC, photosynthetic performance, grain yield, and grain water use efficiency (WUEg) of plastic-mulched maize in a semiarid environment. Treatments were conventional tillage (CT), rotary tillage (RT), subsoiling (SS), and no-till (NT). Soil water content in the 0–30 cm depth with SS was 24, 31, and 13% greater at the flowering, kernel milk, and physiological maturity stages of maize phenological development, respectively, compared to CT. These improvements in SWC were associated with increased leaf water potential (17%), net assimilation rate (41%), transpiration rate (54%), and stomatal conductance (42%), and decreased intercellular CO2 concentration (15%) and stomatal limitation (20%) with SS compared to CT. Subsoiling used more water (9%) and increased grain yield by 21% compared to CT, thus enhancing WUEg by 11%. On average, reduced tillage systems had improved performance (SS > NT > RT > CT) for almost all parameters measured. These results show that SS is a viable option for increasing grain production of plastic-mulched maize in semiarid areas.