Ridge Tillage Research Articles

Changes in soil organic carbon stocks under 10-year conservation tillage on a Black soil in Northeast China

SUMMARYBiased assessment of tillage impacts on soil organic carbon (SOC) sequestration are often associated with a lack of information on the initial level of SOC stocks. The present study reported the changes in SOC concentrations and stocks following 10-year different tillage practices relative to the initial SOC levels. The tillage trial included no tillage (NT), ridge tillage (RT) and mouldboard plough (MP) on a Black soil (Hapludolls) in Northeast China. Results showed that tillage, soil depth and time significantly affected SOC concentration and SOC stock. Tillage and crop residue retention had great impacts on the SOC concentrations in the top 0·1 m layer. Compared with MP and NT, RT resulted in higher SOC concentration and SOC stock in the plough layer (0–0·2 m), which became more obvious with time. The soil under NT and RT had higher stratification ratios (SR) of SOC (SR, the ratio of SOC concentration in 0–0·05 m to that in 0·1–0·2 m) than under MP. Significant positive and nearly identical linear relationships between the SR of SOC and the duration of tillage practices occurred for both NT and RT soils; the increased SR in NT resulted from both SOC increase in surface and SOC decrease in subsurface soils, but in RT, the increased SR was only from a substantial SOC increase in surface soil. Accordingly, the present study highlights that RT was more helpful than NT in carbon sequestration for the studied Black soil in Northeast China.

Soil properties after conversion to conservation agriculture from ridge tillage in Southern Malawi

A study was carried out to assess some of the likely early impacts on soil properties in small-scale farmers' fields following conversion to conservation agriculture (CA) from annual ridge tillage (RT). Five fields under CA applied for 2 years (CA2 yr) and 5 years (CA5 yr), respectively, were paired with adjacent RT fields with similar soil type and maize genotypes. Soils samples from the 20 fields were taken at depths of 0–10 and 10–20 cm and evaluated for physical and chemical characteristics. The results of analysis of variance and mean comparison showed that soil bulk density and total porosity (PORt) largely remained the same between CA and RT fields. Soil structural stability (SI) was marginally greater under CA practices while RT appeared to sustain better soil aggregation and root-zone aeration characteristics (air capacity, AC). CA5yr fields showed greater values for soil organic carbon (OC), total nitrogen, available phosphorous, and cation exchange capacity (CEC). Volumetric water content at field capacity (θfc) and relative water capacity (RWC) were consistently greater under CA applied for the different number of years. The most influential soil attributes with loadings within ten per cent of those with the highest loadings based on multivariate principal component analysis were θfc,θpwp, θs, upper critical bulk density (ρbU), OC, OC-stock, SI, RWC, AC, θfc/PORt, CEC, and K. Thus, soil attributes found as the most important to discriminate either management system were related to volumetric water content, soil organic carbon fraction, air–water storage, and chemical qualities. These were considered suitable for future assessment of soil quality for monitoring land use change effects in similar agroecosystems. The study posits study of socio-ecology of mulch cover practices to attribute management effects on soil properties.

Tillage, seasonal and depths effects on soil microbial properties in black soil of Northeast China

Tillage practice can alter the content and distribution of soil organic matter by burying crop residue and soil disturbance, which would impact soil microbial properties. The objective of the present study was to evaluate the effects of tillage practices (no tillage, NT; ridge tillage, RT; mouldboard plow, MP) and sampling date (April, June, September) on soil microbial properties at different soil depths. Soil core samples were taken at 0–5, 5–10 and 10–20cm depths from a long-term tillage experiment site (initiated in 2001) in black soils in northeast China. Microbial biomass and extractable organic C were determined using by chloroform-fumigation-extraction method. Microbial abundance and community structure were determined using the phospholipid fatty acid (PLFA) method. Principal response curve (PRC) analysis revealed the magnitude of the effect of sampling date on the PLFA relative abundance decreased with depth within the tilled layer, whereas increased with depth for tillage practice. Microbial biomass carbon, abundance and the F/B ratio varied with the variation in available substrates at the 0–5cm depths. NT and RT improved microbial abundance (total, fungal and bacterial abundance) in the 0–5cm depth soil, but they did not contribute to a higher F/B ratio in the 0–5cm depth soil, and had a lower F/B ratio than MP in the deeper soils below 5cm depth. These results demonstrated that long-term conservation tillage practice has potential for improving microbial properties in surface soil, but may not cause a shift of microbial community structure in Northeast China.

Substantiation of location of bottom and top edges of seeding slot of device for ridge tillage with simultaneous application of organic mineral fertilizers

The article presents the results of researches for substantiation of location of bottom and top edges of seeding slot of a device for ridge tillage with simultaneous application of organic mineral fertilizers for the purpose of technological process execution at required level and prevention of fertilizers’ excess consumption.

A simple model to predict soil penetrometer resistance as a function of density, drying and depth in the field

Penetrometer resistance is one of the important soil physical properties that can determine, or be strongly correlated with, both root elongation and yield. We used a field experiment, which was designed to explore the effects of no-tillage (NT) and ridge tillage (RT) on a Mollisols in Northeast China, to test an approach for predicting the effects of soil bulk density, matric potential of water, and depth on penetrometer resistance. The field experiment was initiated in the fall 2010 on a clay loam soil. Soil bulk density, water content, water release curve, and penetrometer resistance were measured during the corn growing seasons in 2012 and 2013. Compared with the RT treatment, NT significantly increased soil bulk density and reduced the fraction of macropores in the 0–20cm soil layer. The increase in density under NT resulted in a higher soil penetrometer resistance, which was associated with a lower water uptake by roots compared with the RT treatment. It was possible to use a relatively simple model for penetrometer resistance to explain the effects of soil bulk density, water status and depth on penetrometer resistance. Depth was included by relating it to overburden pressure. In a penetrometer resistance model that excluded overburden pressure, or depth empirically, penetrometer resistance in deeper layers (>35cm) could not be fitted accurately. The effects of depth on penetrometer resistance from this study were consistent with published data. Our data suggests that at the assessment of soil conditions for root growth, ignoring the effects of depth is likely to give misleading penetrometer resistance.

Soil respiration in a triple intercropping system under conservation tillage

Drivers of soil respiration (Rs) in farmland ecosystem have already been widely studied. However, the relationship between Rs and soil fauna (Fs), hydrothermic factor in the triple intercropping system remains poorly known. An LI-6400 XT portable photosynthesis measurement system equipped with a soil respiratory chamber was adopted in the experimental field. Straw mulching treatment increased soil respiration rate but ridge tillage treatment did not have a consistent effect. A regression analysis of the relationship revealed that exponential equation fitted well the relationship between Rs and soil temperature at 10 cm soil depth. However, the relationship between Rs and soil moisture was best confirmed by a parabolic function. The common dominant groups of Fs in wheat, corn, and soybean farmland were Collembola and Acarina, while Diptera emerged in the two rear crops farmlands. Compared to the control, ridge tillage reduced the number of Fs, but straw mulching increased it and improved the index of soil fauna diversity. In conclusion, the higher was the amount of animals being active above soil surface, the stronger was the soil respiration.

Cover crop and tillage systems effect on soil CO2 and N2O fluxes in contrasting topographic positions

Soils are important sources of CO2 and N2O emissions to the atmosphere. Introducing cover crop and conservation tillage are among the strategies to improve soil organic carbon (SOC) and nitrogen (N) sequestration potentials with potential to reduce the amounts of greenhouse gases (GHG) emitted from soil. The objectives of the study were to evaluate CO2 and N2O emissions in rye cover crop and tillage system treatments in contrasting topographical positions. Two replicated field experiments were established in 2011 at Kellogg Biological Station and Mason Research Farm sites, located in Southwest and Central Michigan, respectively. At each site, two replications of three contrasting topographical positions, namely depression, slope and summit were used. The two studied factors were tillage system (chisel plow and ridge tillage) and winter rye cover crop (present and absent). Topographical positions significantly affected the performance of rye cover crop with above ground biomass ranged from 80 to 200kgha−1 and 120 to >500kgha−1 in depressions and summits, respectively. The presence of rye cover tended to increase CO2 emissions across all topographical positions. However, the amount of increases in the CO2 emissions was ∼15mgm2h−1 and <5mgm2h−1 in depressions and summits, respectively, which were inversely proportional to the amount of rye biomass inputs. Ridge tillage had significantly higher CO2 emissions than chisel tillage in depressions and showed increasing trends at the slopes and summits. Neither the effect of cover crop nor tillage system was found to be statistically significant across the whole study period on N2O emissions. Regression analysis indicated that both CO2 and N2O emissions were positively associated with soil temperature. The effect of temperature on CO2 emissions was most pronounced in management treatments with cover crops and in topographical depressions. Per a unit increase in the soil temperature was a greater increase in the CO2 emission in depression areas than other parts of the landscape. The results of the present study highlight existence of complex interactive influences among cover crop presence, tillage, and topography driven variations in soil properties on the resulting soil GHG emissions.

The potential mechanism of long-term conservation tillage effects on maize yield in the black soil of Northeast China

The severe soil deterioration and the accompanying decline in maize yield are the main factors jeopardizing the sustainability of agricultural production in the black soil region of Northeast China. Conservation tillage practices have been proposed as new practices to enhance soil fertility and to produce food from a dwindling land resource in this region, but wide adoption of these practices can occur only when the practices demonstrate a steady increase in agricultural production. To compare the effects of tillage on corn yield, the structural equation modeling (SEM) was used in analyzing the relationships between maize growth/yield and soil properties (physical and chemical characteristics) based on a long-term (12 years) tillage study that included no tillage (NT), ridge tillage (RT) and conventional tillage (CT) practices. Compared with CT, NT and RT had higher maize grain yield, soil carbon/nitrogen ratio and soil moisture, and lower soil temperature and seedling emergence rate. The advantages of NT and RT in maize yield were primarily ascribed to the favorable soil nutrients and soil water content, which could increase plant size at the later growing season and ultimately yield more maize grain. The lower soil temperature and subsequently lower emergence rates in NT and RT at early stages (sowing to emergence) of maize growth did not exert negative effects on maize yield. These adverse effects of low soil temperature and low emergence rates could be offset by postponing sowing date without compromising the maize yield. Our study indicated that both NT and RT practices could offer a potentially significant improvement over the current conventional tillage practice in the black soil region of Northeast China.

Long-term conservation tillage influences the soil microbial community and its contribution to soil CO2 emissions in a Mollisol in Northeast China

Conservation tillage can significantly affect the biological, chemical, and physical properties of soil. This study aimed to determine the effect of conservation tillage on the soil microbial community and respiration and on soil CO2 emissions. In this study, the effects of 10 years of conservation tillage (no-till: NT and ridge tillage: RT) on soil CO2 fluxes and soil microbial communities were assessed in a black soil in Northeast China. The annual soil CO2 emissions were higher under moldboard plow (MP) than under NT by 7.8 % (P < 0.05). The average soil microbial respiration rate from RT was higher than that from MP by 11 % (P < 0.05). Soil microbial respiration under NT (65 %) and RT (64 %) contributed more to soil CO2 emissions than MP (54 %). Total soil bacterial and fungal phospholipid fatty acids (PLFAs) were 1.6 times and 2.6 times greater under NT and RT, respectively, than under MP in the 0–5 cm layer, whereas they decreased by 21–47 % under NT and 26–41 % under RT in the 5–10, 10–20, and 20–30 cm layers. The F:B (the ratio of soil fungal PLFAs to bacterial PLFAs) varied with soil depth (0–10 cm) between conservation tillage (NT and RT) and MP. Conservation tillage induced the stratification of the soil microbial community on the vertical profile. RT increased soil microbial respiration, soil organic carbon (SOC) concentration, and soil microbial PLFAs at the 0–5 cm depth, whereas it did not influence the annual soil CO2 emissions compared to MP with a similar carbon input. These results suggested that RT might be an appropriate tillage practice for providing a better habitat for soil microbes and SOC sequestration in Northeast China.

Effects of ridge tillage on photosynthesis and root characters of rice

Rice (Oryza sativa L.) is an important crop and breeding has not been able to improve yield. Root characteristics of hybrid rice 'Zhuliangyou 02' under conventional tillage and ridge tillage were studied in a Calcisols in Huaihua, China, from 2011 to 2013 to find better tillage methods to resolve massive water consumption, improve yield, and enhance productivity of agricultural labor for rice cultivation. Results showed ridge tillage increased photosynthetic parameters such as photosynthetic rate (PN), stomatal conductance (gs), and water use efficiency (WUE). It also significantly enhanced rice root number, root activity, and antioxidant enzyme activities; it also increased effective panicle number and actual yield by 22.12% and 15.18%, respectively, and enhanced aerenchymae during the early growth stage. Overall, ridge tillage could promote hybrid rice yields by enhancing root absorption, gas exchange, and reducing water consumption. It could be widely used in rice cultivation.

Effect of Tillage on the Growth and Yield of Cowpea Varieties in Sudan Savanna Agroecology of Northern Nigeria

Field study was conducted during the rainy seasons (July-November) of 2007, 2008, 2009 and 2010 at the Research Farm of the International Institute of Tropical Agriculture (IITA) Minjibir, Kano State, Nigeria; to compare responses of six cowpea varieties to tillage. The treatments consisted of tillage systems (zero tillage, flat tillage and ridge tillage) as the main plot and cowpea varieties (IT89KD-391, IT90K-277-2, IT97K-461-4, IT97K-499-35, IT98K-131-2, and IT98K-506-1) as the sub-plot. The treatments were arranged as split plot laid out in a randomized complete block design with four replications. Zero tillage was significantly superior in influencing days to maturity, canopy height, intercepted Original Research Article Ewansiha et al.; ARRB, 5(3): 275-284, 2015; Article no.ARRB.2015.030 276 photosynthetic active radiation (IPAR) and leaf area index but not total dry matter and grain yield of cowpea. A positive and significant association was recorded for days to physiological maturity and canopy height across the tillage systems with a correlation coefficient of ≤ 40% for days to maturity and ≥50% for canopy height. Though flat tillage showed a positive correlation with intercepted photosynthetic active radiation (IPAR) and leaf area (LAI), but this association was not significant. However, ridge tillage showed a positive and significant correlation with IPAR and LAI (r =0.378*** and 0.384***). All the tillage systems showed a high and significant positive correlation with cowpea dry matter and fodder yield (r= 0.54*** to 0.77***). Across varieties, grain yield was better with flat tillage than zero and ridge tillage systems, with 10% yield advantage over the two. Zero and ridge tillage were similar in their effects on grain yield. Except for IPAR, LAI and total dry matter (TDM), the interaction effect of cowpea varieties and tillage systems was significant. Our result point to the fact that extensive soil tillage (especially, conventional tillage) may not be necessary for cowpea production in this agro-ecology with a high percentage of sand and a sandy loam as soil textural class. Following our result, we may recommended varieties for the different tillage systems as follows: IT98K-131-2, IT97K-461-4, IT90K-277-2, IT98K-506-1 (grain) and IT89KD-391/IT97K-4614 (best for fodder) for zero tillage system; IT90K-277-2, IT97K-499-35, IT98K-131-2 and IT98K506-1(grain) and IT89KD-391/IT97K-499-35 (best for fodder) for flat-tillage; IT98K-131-2, IT90K277-2, IT98K-506-1 and IT97K-464-4(grain) and IT90K-277-2/ IT89KD-391 (best for fodder) for ridge tillage).

Conservation tillage positively influences the microflora and microfauna in the black soil of Northeast China

Soil food webs are important in maintaining agricultural productivity and ecosystem health. However, our understanding is still limited with respect to the influences of tillage transitions on soil food webs. The present study aimed to quantify the response of microflora and microfauna, and their linkage to different tillage treatments: no tillage (NT), ridge tillage (RT) and conventional tillage (CT). Soil samples were collected from 0 to 20cm depth in April of 2011 after 10 years of conservation tillage. The abundance and richness of bacteria and arbuscular mycorrhizal fungi were greater in NT and RT than in CT. In case of microfauna also, similar patterns were observed with greater protozoa, bacterivores and omnivores–carnivores in NT and RT compared to CT. The connectance of the bacterial and predator–prey pathways was greater in NT and RT than in CT and that of fungal pathway was greatest in RT. The trophic relationship of the bacterial and predator–prey pathways was strengthened due to the higher water content of soil and the lower NO3–-N after the conversion of CT to NT and RT. Our study suggested that 10 years of conservation tillage can effectively enhance the structure and function of soil food webs through bottom–up effects in the black soil region of Northeast China.

Effects of conservation tillage practices on ammonia emissions from Loess Plateau rain-fed winter wheat fields

Ammonia emissions from agricultural activities contribute to air pollution. For the rain-fed winter wheat system in the Loess Plateau there is a lack of information about ammonia emissions. Current study aimed to provide field data on ammonia emissions affected by conservation tillage practices and nitrogen applications. A two-year field experiment was conducted during 2011–2013 wheat growing seasons followed a split-plot design. Main plots consisted of one conventional tillage (CT, as the control) and five conservation tillage systems, i.e., stalk mulching (SM), film mulching (FM), ridge tillage (RT), ridge tillage with film mulch on the ridge (RTfm), and ridge tillage with film mulch on the ridge and stalk mulch in the furrow (RTfmsm); while subplots consisted of two nitrogen application rates, i.e., 0 and 180 kg Nha−1. Ammonia emissions were measured using an acid trapping method with vented chambers. Results showed ammonia fluxes peaked during the first 10 days after fertilization. On average, nitrogen application increased ammonia emissions by 26.5% (1.31 kg Nha−1) compared with treatments without nitrogen application (P < 0.05). Ammonia fluxes were strongly dependent on soil ammonium, moisture, and temperature. Tillage systems had significant effects on ammonia emissions. On average, conservation tillage practices reduced ammonia emissions by 7.7% (0.46 kg Nha−1) compared with conventional tillage (P < 0.05), with FM most effective. Deep-band application of nitrogen fertilizer, stalk mulches, and film mulches were responsible for reductions in ammonia emissions from nitrogen fertilization in conservation tillage systems, thus they were recommended to reduce ammonia emissions from winter wheat production regions in the southern Loess Plateau.

Effect of Tillage Operations on Soil Moisture Contents in the Southern Guinea Savanna Ecological Zone of Nigeria

An experimental farm plot was set up at the National Centre for Agricultural Mechanization (NCAM), kilometer 12 Ilorin-Idofian Road to investigate the effect of various agronomic operations (mound, ridge and plough tillage) on soil moisture content of varying depth intervals of 0 - 15 cm, 15 - 30 cm, 30 - 45 cm and 45 - 60 cm respectively. The experiment was conducted between year 2007 and 2009. Samples were taken on weekly basis from various depths using hand screw auger. The percentage moisture was determined by oven drying oil sample to a constant weight at the temperature of 105°C. The difference between the initial weight and weight after oven drying was calculated and the percentage determined. Weekly data generated were grouped on monthly basis and the means calculated. Seasonal values were also calculated. ANOVA and the Post Hoc multiple comparison were employed to investigate variations in soil moisture content between tillage systems and within the four soil depths. The result showed mound tillage to be the driest and ridge was then wettest of all the tillage system considered. The difference between varying intervals of seach tillage became more pronounced between depth intervals of 0 - 15 cm and 15 - 30 cm. Generally, the result of ANOVA indicates seasonal variation in soil moisture between the three tillage methods at all depths considered. Again the result of the Pos Hoc multiple comparison shows that variation in soil moisture content between the 3 tillage systems in wet and in dry season in not significant because the p value > 0.05. Suggestions were made on the way forward towards achieving a self sufficient food production status.

Ridge Tillage Concentrates Potentially Mineralizable Soil Nitrogen, Facilitating Maize Nitrogen Uptake

Ridge tillage (RT) can promote increases in soil C and aggregation at greater rates than conventional tillage, but few studies have investigated how RT may affect soil N distributions across the row/inter-row space. Using a spatially intensive sampling design, we monitored soil potentially mineralizable N (PMN), inorganic N, and plant tissue N in a field study comparing RT and chisel plow (CP) systems. Experiments were fully replicated at two sites in Urbana, IL and Mason, MI during the 2012 growing season. At both sites, a strong interaction effect of tillage × row position was observed for PMN (Illinois, p = 0.005; Michigan, p = 0.02) with higher levels of PMN in the in-row (IR) position than off-row (OR) and between-row (BR) positions of RT treatments following re-ridging. Plant tissue analyses indicated a significant RT advantage at both sites (Illinois, p = 0.04; Michigan, p = 0.02), and a structural equation modeling (SEM) analysis indicated that PMN at the 0- to 5-cm depth in the IR position following re-ridging had a significant effect on inorganic N at the same position and, in turn, a strong influence on plant tissue N (comparative fit index = 0.86, standardized root mean square residual = 0.11, Akaike wt. = 1). Overall, our results suggest that RT can establish soil functional zones (SFZ) with distinct N profiles and that the relocation of PMN in-row may increase the spatial efficiency of N provisioning relative to conventional tillage.

Soil properties after change to conservation agriculture from ridge tillage in sandy clay loams of mid‐altitude Central Malawi

AbstractA comparative study was carried out of annual ridge tillage (RT) and short‐term effects of conservation agriculture (CA) on soil properties in fields of small‐scale farmers. Soil samples were collected at depths of 0–10 and 10–20 cm from a total of 12 fields which had been under CA for two and four seasons, respectively, and from adjacent RT fields for direct comparisons. CA fields were converted from fields previously under continuous RT. Soil organic carbon, total nitrogen and available phosphorus were greater in CA fields while extractable potassium, pH and salt content were moderated under CA. Conversion of long‐term RT to CA did not significantly influence bulk density and aggregate stability (geometric mean diameter) although structural stability was greater under CA practices. Total porosity, macroporosity and matrix porosity, and volumetric water content at saturation, field capacity and permanent wilting point did not substantively respond to tillage effects. Relative water capacity and air–water storage parameter, θfc/PORt, were significantly greater after 4 yr of CA. Soils under CA showed greater values for field‐saturated hydraulic conductivity compared with RT fields. With the highest loadings in a principal component analysis, this work suggests that variables related to volumetric water content and aeration of the soil matrix, organic carbon, available phosphorus and soil texture were the most useful indices for future field comparison of RT and CA practices.

Spatial distributions of soil chemical and physical properties prior to planting soybean in soil under ridge‐, no‐ and conventional‐tillage in a maize–soybean rotation

AbstractDetailed information on the profile distributions of agronomically important soil properties in the planting season can be used as criteria to select the best soil tillage practices. Soil cores (0–60 cm) were collected in May, 2012 (before soybean planting), from soil transects on a 30‐yr tillage experiment, including no‐tillage (NT), ridge tillage (RT) and mouldboard plough (MP) on a Brookston clay loam soil (mesic Typic Argiaquoll). Soil cores were taken every 19 cm across three corn rows and these were used to investigate the lateral and vertical profile characteristics of soil organic carbon (SOC), pH, electrical conductivity (EC), soil volumetric water content (SWC), bulk density (BD), and penetration resistance (PR). Compared to NT and MP, the RT system resulted in greater spatial heterogeneity of soil properties across the transect. Average SOC concentrations in the top 10 cm layer were significantly greater in RT than in NT and MP (P = 0.05). NT soil contained between 0.8 and 2.5% (vol/vol) more water in the top 0–30 cm than RT and MP, respectively. MP soil had lower PR and BD in the plough layer compared to NT and RT soils, with both soil properties increasing sharply with depth in MP. The RT had lower PR relative to NT in the upper 35 cm of soil on the crop rows. Overall, RT was a superior conservation tillage option than NT in this clay loam soil; however, MP had the most favourable soil conditions in upper soil layers for early crop development across all treatments.

Impact of tillage on physical characteristics in a Mollisol of Northeast China

Soil management is aimed at the maintenance of optimal soil physical quality for crop production. In order to explore the effects of tillage practices on soil physical properties, a study was conducted to compare the effects of no tillage (NT), moldboard plow (MP) and ridge tillage (RT) on soil bulk density (BD), soil penetration resistance (SPR), soil water content (SWC), soil macroporosity (MAC) and soil air-filled porosity (AFP) in Northeast China. Results showed that both NT and RT led to significant BD increment than MP at 0&amp;ndash;20 cm (P &amp;lt; 0.05). Compared with MP, NT and RT increased SPR at the depths of 2.5&amp;ndash;17.5 cm (P &amp;lt; 0.05). SWC of 0&amp;ndash;10 cm layer was significantly higher in NT and RT than MP soils (P &amp;lt; 0.05). NT showed a significantly lower MAC than MP and RT at 0&amp;ndash;20 cm soil depths (P &amp;lt; 0.05). All AFP values were above the limit of 0.10 cm&lt;sup&gt;3&lt;/sup&gt;/cm&lt;sup&gt;3&lt;/sup&gt; under all tillage treatments. RT improved the soil physical quality as evidenced by decreased BD and SPR, and increased SWC, MAC and AFP relative to NT.

Short-term effect of tillage and crop rotation on microbial community structure and enzyme activities of a clay loam soil

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.

Recent progress and prospects in the development of ridge tillage cultivation technology in China

The trace of high and low ridge in the Sanyangzhuang village site showed that adopting ridge tillage cultivation technology (RT) in China has a long history of more than 2000 years. In this paper, we reviewed recent advances of the development and application of RT in China. The better yields from crops grown on ridges/furrow compared with those on flat land were attributed mainly to the improvement of soil moisture conditions, better air permeability and effective supply of soil nutrition. However, most studies of RT are mainly concentrated in upland crop. It has not been reported on RT's higher water use efficiency (WUE) and the capacity of drainage & impounding during the rice production process. New systems of ridge tillage & terrace cultivation model (RTT) for irrigated rice are described here. Further research is needed to optimize management strategies and to strengthen basic research for RTT to obtain environmental and economic benefits and to evaluate practicability and effectiveness of RTT in the paddy field.