Ridge Tillage Research Articles

GNSS Esaslı Traktör Otomatik Dümenleme Sistemlerinin Ekim İşleminde Paralel Geçişlerde Sıra Arası Mesafe Düzgünlüğüne Etkisi

Precision agriculture (PA) includes advanced technologies to increase efficiency and profitability of agricultural operations from tillage to harvest and offers sustainability of the natural resources and the environment. Automatic steering (AS) is the mostly-used PA technology in the world and in Türkiye providing many benefits. It has potential for efficient and sustainable agronomic practices including soil ridge tillage and sowing. Adequate spacing is needed to provide equal living area for each plant in sowing. Thus, in mechanized planting, pass-to-pass plant inter-row spacing (PIRS) should be equal in parallel passes. Research on the benefits of the AS for providing uniform PIRS in sowing is very limited. This work aimed to appraise the pass-to-pass PIRS deviations in planting with GNSS-based AS with three signal correction sources (RTK, CORS, SBAS) and without AS (manual steering) for comparison. The data were obtained from 24 farmer fields (cotton and corn) with PIRS set values of 70-75 cm located in the Cukurova region of Türkiye. Pass-to-pass PIRS values were manually measured and the deviations from the set value were analyzed in terms of root mean square error (RMSE). The mean PIRS variations in sowing by manual steering (7.4 cm) were found as significantly higher than the AS based soil ridge tillage and / or sowing (CORS: 5.0 cm, SBAS: 5.9 cm, RTK: 6.7 cm) (p

High leaching potential combined with a low leaching amount of fertilizer-derived nitrate in conservation tillage cropland of Northeast China

Stover mulching in no-tillage farming has been widely proposed as an optimized agricultural management practice to increase soil carbon storage and improve fertilizer nitrogen (N) use efficiency in current agroecosystems. However, the regulation of soil internal gross N transformation dynamics on NO3−-N leaching potential in response to long-term conservation tillage practices is still lacking. Here, based on a combination of 15N-tracing incubation and in situ monitoring experiments, we investigated the effect of 9-year no-tillage and maize stover mulching on the vertical migration of fertilizer-derived NO3−-N into a deeper soil profile and the associated gross NO3−-N transformation dynamics in the Mollisol of Northeast China. The net positive NO3−-N production rates (varied from 3.14 to 6.22 mg N kg−1 d−1) were observed across all management practices in the studied Mollisol, indicating a relatively high NO3−-N leaching potential in the cropland of Northeast China, which was further confirmed by an average of 7.4 % fertilizer-derived NO3−-N being vertically transferred to the 80–100 cm soil layer after a complete maize growing period. Compared with traditional ridge tillage, long-term stover mulching in no-tillage farming significantly reduced total NO3−-N production by decreasing autotrophic nitrification while simultaneously enhancing total NO3−-N consumption by stimulating nitrate reduction and microbial NO3−-N immobilization, revealing a markedly reduction of net NO3−-N production in the no-tillage agroecosystem. Therefore, converting traditional ridge tillage toward no-tillage with maize stover mulching can effectively decrease fertilizer-derived NO3−-N leaching amounts and thus formulate targeted mitigation strategies for sustainable agriculture in Mollisols of Northeast China.

Soil and water conservation effects of different tillage measures on phaeozems sloping farmland in northeast China

AbstractConventional tillage is still widely practiced in phaeozems sloping farmland, which leads to serious soil erosion. Adopting effective farming methods is crucial for mitigating soil erosion. To prevent and control soil and water loss in phaeozems sloping farmland, field experiments were conducted in 2022 using three tillage methods and their combination modes: subsoiling tillage (SF), ridge tillage and pitting field (RF), ridge tillage and pitting field + subsoiling tillage (RF‐S), contour tillage (TP), contour tillage + ridge tillage and pitting field (TP‐R), and contour tillage + subsoiling tillage (TP‐S). The study aimed to assess the impact these different tillage methods on soil and water conservation. The results showed that the contour tillage + ridge field treatment significantly reduced surface runoff and soil loss (p < 0.05), with no observed nutrient loss. Compared with other treatments, this method significantly reduced runoff, erosion, and nutrient loss. In contrast, the contour tillage + subsoiling tillage treatment significantly decreased the soil three‐phase R‐value, improved the soil texture, and exhibited higher yield, harvest index, and water use efficiency (WUE) compared to alternative treatments. Overall, the comprehensive findings indicate that contour tillage + subsoiling tillage can reduce soil erosion, enhance soil quality, and improve the WUE, all while maintaining high production capacity. Furthermore, the results of this study provide a theoretical basis for conserving soil and water resources, improving soil fertility, and increasing farmland yield in the phaeozems area of northeast China.

Effect of Different Tillage Practices on the Growth and Yield of Sweet Potatoes (Ipomoeo Batata L) in Asaba, Delta State Nigeria.

The research was carried out to determine the effect of different tillage practices on the growth and yield of sweet potatoes (Ipomoeo batata L) in Asaba, Delta State Nigeria. Field experiment was carried out at the teaching and research farm of Federal College of Education (Technical),Asaba, Delta State Nigeria. The experiment was laid out in a randomized complete block design (RCBD) made up of four treatments: To – control (ridge tillage), T1 – Zero tillage, T2 – Mound tillage, T3 – Flat tillage and was replicated three times (4 x 3). Land area of 100m x 100m was cleared and divided into three to represent, replicates 1, 2 and 3. Random samples of five plants were tagged for data collection at four, six and eight weeks’ intervals after germination of plants to measure the growth parameters, while yield was measured in kg using weighing scale. Data analysis was carried out using the statistical package of social science (SPSS) with general linear model procedure analysis of variance (ANOVA) to determine the treatment effect and Duncan Multiple Range Test was used for mean separation difference in mean were considered significant at an alpha level of 95% or higher (p ≤ 0.05). Findings from the study revealed that tillage practices had significant effect (p<0.05) on the growth and yield of sweet potatoes. The study recommended the adoption of ridge tillage practices for increased growth and yield of sweet potatoes.

Effects of long-term conservation tillage on N2 and N2O emission rates and N2O emission microbial pathways in Mollisols

Conservation tillage is widely used in farmland management for soil carbon sequestration, but it can also lead to potential emissions of nitrous oxide (N2O). Therefore, our study is aimed to investigate the effects of 15 years of no-tillage combined with four straw mulching levels of 0 % (NT0), 33 % (NT33), 67 % (NT67), and 100 % (NT100) compared to ridge tillage (RT) on the rates of N2O and N2 emissions and the respective contributions of four microbial pathways to N2O emissions. The incubation experiments were conducted at two different moisture levels (55 % and 100 % WFPS) by using dicyandiamide inhibition and 15N-labeling techniques. Soil samples were collected from the 0–20 cm and 20–40 cm soil depths across three maize growth stages: seedling, jointing, and maturity. Our results showed that conservation tillage significantly decreased the N2O + N2 emission at 55 % WFPS, but it has a reverse influence in N2O + N2 emission at 100 % WFPS. The proportion of N2O in gaseous N loss were higher at 100 % WFPS than at 55 % WFPS. Among the four microbial pathways for N2O emissions, autotrophic nitrification was the dominant pathway 55 %WFPS. The contribution of autotrophic nitrification remarkably decreased, co-denitrification and denitrification increased at 100 %WFPS. Overall, at 100 % WFPS, N2O emissions from all major microbial pathways were positively correlated with GWC, temperature, TC, TN, NH4+-N, and NO3−-N, but negatively correlated with soil pH and C/N ratios. Our results suggest that long-term conservation tillage increases N2O and N2 emissions from the soil under water-saturated conditions by regulating soil nutrient levels, soil moisture, and microbial pathways. Therefore, we should consider the impact of conservation tillage on N2O emission risk when we attach importance to the role of conservation tillage in improving soil quality and increasing crop yields.

Long-term conservation tillage improves soil stoichiometry balance and crop productivity based on a 17-year experiment in a semi-arid area of northern China

Although conservation tillage has been widely implemented to address the challenge to improve crop yield and soil quality with fewer environmental costs, its long-term effects on crop yields and soil stoichiometry balance remain uncertain. Here, four different long-term (17-year) tillage practices (conventional tillage (CT), deep scarification (DS), no tillage (NT), and ridge tillage (RT)) were conducted in northern China to evaluate their effects on crop yield, soil nutrients, C sequestration, and soil stoichiometry. The conservation tillage (DS, NT, and RT) increased the recent 5-year average yields by 12.2 %–20.1 % compared with CT, respectively. RT showed the highest C sequestration potential of 10.0 t/ha, followed by DS and NT (6.0 t/ha and 4.4 t/ha, respectively). The DS, NT, and RT enhanced soil available N and K with the best effect for NT, but DS reduced soil total and available P. The conservation tillage significantly increased the C:N, C:P, C:K, and N:P ratios, indicating it sustained soil balanced stoichiometry. Correlation analysis indicated crop yield was closely related to soil C:N, C:P, C:K, and N:P. The structural equation model revealed that the C, N, and P affected C:N and C:P ratios, thus improving crop yield under long-term conservation tillage. In summary, long-term conservation tillage improves soil stoichiometry balance and thus crop yields with great C sequestration potential to achieve sustainable agricultural management in rain-fed farmland.

Multi-attribute parameterization modelling to assess response of microtopographic variation to rainfall-seepage coupled erosion

Slope microtopography redistribution caused by the process of surface–subsurface hydrology results in the randomness and nonlinearity of erosion behavior. However, the erosion effects of various microtopographic features under the rainfall-seepage coupled impact remain inadequately explored. In this work, a specialized parameterization framework was employed, coupling numerical attribute, shape, and structure with the spatial pattern of microtopography, specifically to quantify changes in microtopography and to clarify their response mechanisms to rainfall-seepage erosion on purple soil slopes. The continuous rainfall-seepage simulation experiments were conducted on a 15° tilled-slopes differing in microreliefs (conventional tillage, CT; artificial digging, AD; ridge tillage, RT) with constant rainfall intensity of 1.0 mm min−1 coupling three seepage rates of 2, 4 and 8 L/min, respectively. Results revealed that the elevation decay occurred in the stage of transition from sheet erosion to rill erosion for CT, AD and RT slopes, representing a “erosion > deposition” feature. The numeric roughness and multifractal pattern of microtopography showed RT > AD > CT slope during the rainfall-seepage erosion. The spatial change of microtopography was attributed to structural-oriented factors because the nugget ratio with less than 25 % accounted for 73.33 %. Synchronously, the runoff, sediment yields and concentrations increased with the increase of rainfall-seepage intensity. It was found that the response of roughness index on soil erosion was more obvious for smooth surface with relatively contribution rate of 81 %, while the change of microstructure (H) and multifractal shape (ΔD) were more sensitive to erosion process on AD and RT slopes respectively. The results reported in this study have important implications for an in-depth apprehending of microtopography erosion effects in saturation-excess dominated slope cropland.

Short-term effect of different returning methods of maize straw on the temperature of black soil plough layer

Clarifying the effect of different maize straw returning methods on soil temperature is crucial for optimizing the management of farmland straw and the efficient utilization of heat resources in the black soil region of Northeast China. To investigate the impacts of straw returning methods on soil temperature, we conducted a field experiment with four treatments during 2018 and 2020, including plough tillage with straw returning (PTSR), rotary tillage with straw returning (RTSR), no-tillage with straw returning (NTSR), and a control treatment of conventional ridge tillage without straw returning (CT). We measured soil temperature and water content at the 5 cm, 15 cm and 30 cm soil layer, and the straw coverage rate during the 3-year maize growth period. We further analyzed the differences of soil temperature in different soil layer under different treatments, accumulated soil temperature and growing degree-days (GDD) above 10 ℃, daily dynamics of soil temperature, the production efficiency of air accumulated temperature among different treatments, and explored factors causing the difference of soil temperature and the production efficiency of air accumulated temperature. Our results showed that different treatments mainly affected soil temperature from the sowing to emergence stage (S-VE) of maize. The daily average soil temperature showed a trend of CT>PTSR>RTSR>NTSR. The differences of soil temperature under different treatments showed a decreasing trend as growth process advanced and soil depth increased. Compared with the CT treatment, soil temperature at 5 cm depth was decreased by 0.86, 1.84 and 3.50 ℃ for PTSR, RTSR, and NTSR treatments, respectively. NTSR significantly reduced the accumulated temperature of ≥10 ℃ in different soil layers and GDD. The accumulated temperature ≥ 10 ℃ at the 5, 15, and 30 cm soil layers decreased by 216.2, 222.7, and 165.1 ℃·d, and the GDD decreased by 201.9, 138.7 and 123.9 ℃·d, respectively. In addition, production efficiency of air accumulated temperature decreased by 9.7% to 15.6% for NTSR. Conclusively, PTSR and RTSR had significant impacts on topsoil temperature during the maize growing period from sowing to emergence, but did not affect the accumulated soil temperature and the production efficiency of air accumulated temperature. However, NTSR significantly reduced topsoil temperature and production efficiency of air accumulated temperature.

Reduction of NH3 Emissions from Urea by Long-Term No-Tillage and Stover Mulching with Inhibitors: An Isotopic Field Study in Northeast China

Large nitrogen (N) losses during fertilization in agricultural production may result in energy wastage, soil and water contamination, and potentially influence crop development. Thus, with the help of a 15N-labeled tracer, we carried out a field monitoring analysis of NH3 emissions in a long-term (9-year) conservation tillage agroecosystem of Mollisols in northeast China, in order to determine whether a no-tillage regime and four levels of stover mulching (0%, 33%, 67%, and 100%), combined with urease and nitrification inhibitors, could improve fertilizer utilization efficiency in agricultural systems by reducing ammonia volatilization. Our results showed that in comparison with ridge tillage, no-tillage with stover mulching levels of 33%, 67%, and 100% significantly reduced NH3 emission rates and cumulative volatilization from 159.67 to 130.42 g N ha−1 and 15N-NH3 cumulative volatilization emission by 26% (on average). Furthermore, the application of urease and nitrification inhibitors significantly reduced 15N-NH3 volatilization levels from 1.19 to 0.98 g N ha−1. Our research results demonstrate that a long-term no-tillage regime and straw mulching can significantly reduce NH3 volatilization in fertilizers. Furthermore, when combined with the use of urease and nitrification inhibitors, these practices further enhance the reduction in NH3 volatilization. Although the volatilization of 15N-NH3 is minimally studied in Mollisols, these findings provide a solid foundation for improving fertilizer utilization efficiency, reducing crop production costs and mitigating subsequent environmental pollution.

Using rare earth element tracers to investigate ridge slope erosion process in contour ridge system under extreme rainfall

Extreme rainfall is becoming more frequent and intense, which no doubt increases the risks and uncertainty of water erosion in widely-used contour ridge systems. Ridge slope erosion can increase the probability of contour failure occurrence and then induce contour ridge losing anti-erosion properties. However, there is little understanding of ridge slope erosive process controlled by contour ridge system responding to extreme rainfall. In this study, five rare earth elements were applied in different ridge segments and soil layers to monitor the successive development of ridge slope erosion process under extreme rainfall in contour ridge system. Simulated rainfall experiments at high rainfall intensity (100 mm h−1) lasting for 60 min were conducted in runoff plots with ridge tillage practices characterized by microtopography indices and ridge geometry indices. Results showed that three sub-processes were observed for ridge slope erosion, including inter-rill erosion, headward erosion, and rill erosion. Headward erosion mainly resulted from the break-point at ridge surface and sidewall collapse at ridge toe, and the pouring of ponding water in furrow greatly promoted rill development. Erosion rate was the largest during headward erosion process, and rill erosion contributed the most to eroded source. The dominated erosion process was transport-limited during inter-rill erosion process, and detachment-limited during headward and rill erosion processes. Sediment transport and deposition processes as well as their transformation occurred simultaneously after the development of headward erosion. Eroded sediment was mainly from the low part of ridge, which was transported by raindrop-impacted sheet flow or overflow. These findings provide better responding of agricultural tillage to global climate change and references for the development of physically-based erosion models.

Composite Factors during Snowmelt Erosion of Farmland in Black Soil Region of Northeast China: Temperature, Snowmelt Runoff, Thaw Depths and Contour Ridge Culture

Snowmelt erosion could cause serious damage to soil quality and agricultural production conditions of slope farmland in the black soil region of northeast China. Contour ridge tillage is a traditional and effective measure to mitigate soil loss on slope farmland. However, the characteristics and influence factors of snowmelt erosion of slope farmland with contour ridge culture and the effect of this measure on the snowmelt process have not been comprehensively investigated, especially at the field scale. To bridge the gap, in situ observation was conducted on the snowmelt erosion process of a typical farmland in Baiquan County, Heilongjiang Province, China. The results revealed that during the snowmelt erosion period, the average daily snowmelt runoff volume and sediment concentration exhibited a trend of first increase and then a subsequent decrease. In the early stage, although the sediment concentration was large, limited discharge and soil thaw depths led to minimal soil loss. In the following stage, due to increased runoff and thaw depths, 94% of the total soil loss amount was obtained with an obvious erosion path formed. For each event, when soil thaw depths were shallow, sediment concentration had a high and early peak, whereas a reverse trend was observed when thaw depths increased. The hysteresis relationship of discharge–sediment indicated that the location where snowmelt erosion primarily occurred would change, under the influence of variations in runoff, freeze and thaw action, thaw depths, and micro-topography. The results could provide a guide in the control of soil erosion in seasonal snowmelt-erosion-prone areas.

Study on characteristics of soil and nutrient losses in Sunjiagou small watershed in cold black soil area.

Investigating the impact of different factors on soil and nutrient loss and suggesting viable control measures is currently a significant concern. This study aims to examine the variations in soil erosion, as well as nitrogen and phosphorus loss, in the core area of the typical hilly diffuse Blackland erosion control. To achieve this, runoff plots with slopes of 3° and 5° were set up in the Sunjiagou sub-basin, located in the upper reaches of the Feiketu River. These plots were subjected to various soil and water conservation measures, along with different levels of vegetation cover. This study aims to analyze the soil and nutrient loss patterns and characteristics in each runoff plot during the natural rainfall events occurring between 2020 and 2022. The results show that soil and nutrient losses are highly significantly and positively correlated with rainfall intensity. The RUSLE model demonstrates a better fit for both cross ridge tillage and bare ground. The loss of nitrogen was much more significant than that of phosphorus, and nitrate nitrogen is the main form of nitrogen loss. Nitrogen loss is mainly dominated by nitrate nitrogen (NN), which is easily soluble in water and constantly migrates with runoff due to the negatively charged NN (NN accounted for 45.2% ~ 81.8% of total nitrogen (TN)). In contrast, the positively charged ammonia nitrogen (AN) is more stable in combination with the soil; large losses only occur under severe sediment erosion. Phosphorus is easily attached to sediment, and the high sediment production leads to a more serious loss of total phosphorus (PP) in the particulate state (PP accounts for 72.7% ~ 96.2% of total phosphorus (TP)). Changing longitudinal ridge tillage to cross ridge tillage and planting vegetation with better water retention and sediment fixation as plant hedges can effectively prevent the loss of soil, runoff, nitrogen, and phosphorus.

Conservation strip-till modifies rhizosphere ammonia-oxidizing archaea and bacteria, increases nitrate accumulation and promotes maize growth at grain filling stage

Strip-till (ST) is a conservation tillage wherein the “inter-row” is not tilled and remains covered with protective residues, while the “row zone” is strip tilled. In comparison to conventional ridge tillage (CT), maize yield under ST is maintained due to its growth recovery at grain filling stage (GFS), though its growth lag at early growth stage in cold regions. To explore microbial mechanisms underlying the growth recovery, compared with CT, we investigated relationships among rhizosphere ammonia-oxidizing archaea and bacteria (AOA and AOB), rhizosphere soil characteristics, and maize growth under ST through a two-year field experiment in a Mollisol of Northeast China. Compared with CT, ST led to rhizosphere NO3--N accumulation at 0–5 cm location, which positively correlated with maize N accumulation and growth at GFS. ST significantly affected rhizosphere AOA and AOB communities at 0–5 and 20–30 cm locations, and decreased AOA abundance, norank_p_Thaumarchaeota relative abundance and bio-markers, but increased AOB abundance, richness, Nitrosospira relative abundance and bio-markers at 0–5 cm location. ST obviously increased the number of OTU hubs belonging to AOB Nitrosospira in networks and their complexity at 0–5 cm location. AOB community play a more important function role than AOA at 0–5 cm location. Rhizosphere NO3--N accumulation, maize N accumulation and growth recovery were closely related with AOB (especially Nitrosospira), but not AOA. It is concluded that, in contrast to CT, ST mainly stimulate rhizosphere AOB activity at 0–5 cm location (especially Nitrosospira) during grain filling stage, which contributes to more rhizosphere NO3--N accumulation and maize N absorption and faster growth. Our findings provide a theoretical basis for efficient crop-soil management to increase maize productivity under conservation tillage system.

Ridge tillage increased halophyte fine root production and turnover rates by altering soil properties in an abandoned farmland in northwest China

Ridge tillage is a common tillage practice used for farmlands and afforestation. However, the mechanisms by which ridges affect halophyte fine root dynamics in abandoned farmlands are still unknown. A field experiment was conducted to evaluate the effect of ridge tillage on root dynamics in an abandoned farmland over three consecutive years using a minirhizotron method. The rate of fine root production varied from 27 to 44 mm cm−2 each year, and the root turnover rate was between 7.46 and 16.99 times per year. Ridge tillage significantly decreased 0–1 mm diameter root production and root lifespan (28.98% and 19.77%, respectively) while increasing root mortality by 18.74%. Conversely, there was no significant effect of ridge tillage on roots within the 1–2 mm diameter range. Ridge tillage resulted in increased root production and root lifespan, which was mainly due to an increase in soil moisture. Clear seasonal patterns were observed for fine root production, root standing crop and root mortality due to increases in soil organic matter, soil water content and soil salt content in the abandoned farmland. Our results demonstrated that ridge tillage not only accelerated halophyte root production and lifetimes but also improved belowground productivity, providing a potential way to replant in the saline-alkaline soils of abandoned farmlands.

Effects of microtopography change driven by seepage and slope gradients on hillslope erosion of purple soil

Seepage is the prominent hydrological process on tilled hillslopes covered by purple soil, which can easily exacerbate slope instability and soil loss. Laboratory simulated experiments with a seepage intensity of 4 L min−1 under different slope gradients (5°, 10°, and 15°) were conducted to analyze how seepage induced the erosion impacts the microtopographic change during water erosion process. Three tillage practices, i.e., smooth slope (CK), artificial diffing (AD) and ridge tillage (RT) with different initial microrelief were designed in this study. Results showed that the variation of soil surface roughness (SSR) to seepage erosion showed CK > AD > RT, and the most severe on the midslope and downslope, fluctuating from −4.23% to 12.40%. The sharpness of soil surface microtopography (SSM) on RT and AD decreased as the slope gradient increased. Compared to CK, AD and RT effectively controlled runoff loss. Both AD and RT were unable to reduce soil loss when the seepage duration exceeded 45 min, that was, the sediment yield increased by 815.50% and 730.25%, respectively. The response of surface runoff and sediment yields to microtopography changes was characterized applying multivariate linear equation. The applicability of multifractal parameters was weakened in the terms of the response to soil erosion caused by seepage. In contrast, the contribution rate of RUp to soil erosion was 69.40% and that of RDown was 58.76% in SSR indexes under seepage condition, which were the optimal parameters assessing the changes of surface runoff and sediment yields. This study contributes to elucidating seepage erosion effects in purple soil slope and understanding hydrological processes based on SSM changes.

Multi-temporal spatial modelling to assess runoff and sediment dynamics under different microtopographic patterns

Soil erosion is a multi-scale geographical interface process with high spatiotemporal variability. This study aimed to assess runoff and sediment dynamics under different microtopographic patterns based on wavelet analysis and SIMulated Water Erosion model (SIMWE). Three rainfall intensities of 1.0 mm min−1, 1.5 mm min−1, and 2.0 mm min−1, combined with three slope gradients of 10°, 15°, and 20°, were utilized to conduct rainfall simulations on three soil boxes measuring 4 m in length and 0.8 m in width. The soil boxes exhibited distinct microtopographic patterns, including smooth slope (CK), artificial digging (AD), and ridge tillage (RT). The results showed that the runoff and sediment reduction benefits of different tilled slopes decreased with an increase in both slope and rainfall intensity. The AD and RT slopes reduced runoff yields by 8.4% − 50.2% and 17.3% − 75.0% respectively compared to CK slope. Although sediment yields from AD and RT slopes were reduced by 4.2% − 51.6% and 1.8% − 53.0%, respectively, the sediment control benefits of AD and RT slopes were basically lost when the slope gradient increased to 20°. The rill erosion was the main source of soil erosion on different tilled slopes, accounting for 72% − 87% of the total soil loss. And the rates of both soil erosion and rill erosion exhibited a power function relationship with an increase in rainfall intensity and slope. The impact of slope gradient on soil erosion on the RT slope was greater than those on the CK and AD slopes. During the development of rill erosion, non-stationary and multi-scale periodic phenomena exist in the time series of runoff and sediment on different microreliefs. As surface microrelief increased, the fluctuations in runoff and sediment on tilled slopes intensified, resulting in a gradual shortening of the variation period. And this study verified the feasibility of the SIMWE model to simulate the runoff and sediment dynamics on microtopographic scale under a single rainfall event. The results can provide a theoretical basis for the scientific layout of soil and water conservation practices in sloping farmland and the construction of soil erosion model in purple soil area.

Impacts of land use and soil conservation measures on runoff and soil loss from two contrasted soils in the black soil region, northeastern China

AbstractRunoff and soil loss characteristics on slopes and their responses to soil conservation measures and soil properties have not been fully understood. In the present study, runoff and sediment data from runoff plots with two contrasted soils (i.e., Phaeozenm and Luvisols) at the Liangshigou (LSG) and Erdaogou (EDL) catchments were used to study soil loss characteristics for the black soil region, northeastern China. The implemented soil conservation measures including cross ridge tillage, hedgerow, terrace, level trough, and biological measures can effectively control soil loss at the two sites, whereas the downslope ridge tillage (DRT) and bare plots yielded annual soil loss rates of 1230 t km−2 year−1 in 2014–2015 and 2020 and 580 t km−2 year−1 in 2020 which were much higher than the tolerable value (i.e., 200 t km−2 year−1). Under the same treatments, the Phaeozenm plots yielded much higher soil loss rates than the Luvisols plots, resulting from more erosive rainfall events and higher soil erodibility at the LSG catchment. The typical black region with the Phaeozenm soil should be the priority area to be implemented with soil conservation measures in northeastern China.

Mechanisms of conservation tillage on nitrogen-fertilizer reduction and maize grain improvement in Mollisols of Northeast China: Insights from a 15N tracing study.

Conservation tillage is an important management practice to guarantee soil fertility in degraded Mollisols. It is still unclear, however, whether the improvement and stability of crop yield under conservation tillage can be sustainable with increasing soil fertility and reducing fertilizer-N application. Based on a long-term tillage experiment initiated in Lishu Conservation Tillage Research and Development Station by Chinese Academy of Sciences, we conducted a 15N tracing field micro-plot experiment to investigate the effects of reducing nitrogen application on maize yield and fertilizer-N transformation under long-term conservation tillage agroecosystem. There were four treatments, including conventional ridge tillage (RT), no-tillage with 0% (NT0), 100% (NTS) maize straw mul-ching, and 20% reduced fertilizer-N plus 100% maize stover mulching (RNTS). The results showed that after a complete cultivation round, the average percentages of fertilizer N recovery in soil residues, crop usage, and gaseous loss were 34%, 50%, and 16%, respectively. Compared with conventional ridge tillage, no-tillage with maize straw mulching (NTS and RNTS) significantly increased the use efficiency of fertilizer N in current season by 10% to 14%. From the perspective of N sourcing analysis, the average percentage of fertilizer N absorbed by crop parts (including seeds, straws, roots, and cobs) to the total N uptake reached nearly 40%, indicating that soil N pool was the main source of N for crop uptakes. In comparison with conventional ridge tillage, conservation tillage significantly increased total N storage in 0-40 cm by reducing soil disturbance and increasing organic inputs, and thus ensured the expansion and efficiency increment of soil N pool in degraded Mollisols. Compared with conventional ridge tillage, NTS and RNTS treatments significantly increased the maize yield from 2016 to 2018. In all, by improving fertilizer nitrogen utilization efficiency and maintaining the continuous supply of soil nitrogen, long-term management of no-tillage with maize straw mulching could achieve a stable and increasing maize yield in three consecutive growing seasons and simultaneously reduce environmental risks derived by fertilizer-N losses, even under the condition of 20% reduction of fertilizer-N application, and thus actualize the sustainable development of agriculture in Mollisols of Northeast China.

A Combined Ridging and Cover Crop Tillage System for Sustainable Coffee Plantation in Kenya

The introduction of ridge tillage and beans as a cover crop was investigated as a means of management for mitigating soil erosion and increasing the physical functionalities of soil. In a completely randomized design, four treatments were applied to twelve plots, three with ridges introduced (T1), three with beans as the cover crop (T2), three with cover crops combined with ridges (T3), and another three as controls without intervention (T4). Four physical properties were monitored, i.e., soil moisture content, bulk density, infiltration rate, and aggregate stability. Data were collected from two seasons with beans as the cover crop, with each season lasting three months. The results showed that T3 resulted in the highest soil moisture content at 34.87 ± 6.78%, followed by T2 and T1 with 34.20 ± 0.65% and 32.65 ± 1.71%, respectively, while T4 had the minimum value of 28.28 ± 5.30%. The bulk density of the soil was found to be lowest at T2 and T3, both having a value of 0.92 g cm−3 with standard deviations of ±0.03 and ±0.11, respectively. This was followed by T1 with 0.98 ± 0.05 g cm−3 while T4 had the highest bulk density of 1.17 ± 0.13 g cm−3. A similar trend was observed for both the basic infiltration rate and aggregate stability, except that, in terms of the latter, T1 was ranking second after T3, with 64.07% of water stable aggregates greater than 0.25 mm diameter. The interventions introduced in coffee plantations had significant effects on the bulk density and infiltration rate; however, there was no significant difference in the moisture content and aggregate stability. Further investigation is needed to quantify the environmental effects of these interventions, e.g., greenhouse gas emissions and yields.

Effects of Three Different Tillage Patterns on Ground and Below-Ground Dwelling Insect Assemblage

Tillage could significantly change the biodiversity in farmlands. As a prominent component of farmland ecology, crops play a key role in regulating biological communities. To explore the effects of tillage patterns and planting modes, including high-disturbance tillage practices and different plant compositions, on the abundance of soil insects, we tested the responses of soil insects to no-tillage (NT), ridge tillage (RT), and fall plow (FP) treatments with different planting modes. The results illustrated that planting modes significantly changed the distributions of ground-dwelling insect species and disturbed interactions on the farmland. Soil-dwelling insect assemblages were mainly influenced by tillage patterns, which reflected that soil physicochemical properties, especially pH, had the highest contribution to the determination of community composition. The no-tillage system supported the highest predator species richness and lower herbivore richness with higher abundance. In the no-tillage system, most of the insects on the farmland have established relationships, forming a relatively high degree of connection between different insects. The network was more specialized and nested in the field with fall ploughing. In conclusion, the effects of tillage patterns and planting modes on insect assemblage can be divided into two spatial dimensions: the success of soil-ground insect maintenance determined by plants and below-ground depended on tillage.