Reduced Tillage Research Articles

Restoring soil carbon in marginal land of Indian Himalayas: Impact of crop intensification and conservation tillage.

Soil carbon (C) loss is the prime sign of land degradation, and C pools have a great impact on soil quality and climate change mitigation. Hence, a field experiment was conducted for three consecutive years to assess the impact of crop intensification and conservation tillage practices on changes in the C pool at different soil depths of marginal land of the Indian Himalayas. The experiment consisted of two intensified cropping systems viz., CS1-Summer maize (Zea mays L.) -rainy season maize-lentil (Lens esculenta L.) and CS2-Summer maize-rainy season maize-mustard (Brassica juncea (L.) Czern) and five tillage practices viz., No-till (NT); NT+live mulch of cowpea (NT+LMC); reduced tillage (RT); RT+LMC and conventional tillage (CT). Results revealed that CS2 produced significantly higher biomass, C retention efficiency (9.85%), and sequestrated greater C (0.42Mgha-1 yr-1) in the soil system than CS1. Of the various tillage practices, RT+LMC registered higher biomass and recycled greater biomass and C than those under other tillage practices. However, the highest soil organic carbon (SOC) content (7.03gkg-1) and pool (9.62Mgha-1) in 0-10cm depth were observed under NT+LMC. The non-labile C pool size under NT in 0-10cm and 10-20cm depths was significantly greater than those under CT. The NT+LMC sequestrated significantly higher SOC (0.57Mgha-1 yr-1) than other tillage practices. Thus, the study indicated that the adoption of an intensified maize-based system under RT+LMC or NT+LMC would increase SOC storage and C sequestration in marginal lands of the Indian Himalayas.

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.

Reduced tillage and rotational diversity improve soil health in Missouri

AbstractThe Missouri Soil and Water Conservation Program was initiated by the Department of Natural Resources (DNR) to address challenges related to soil and water degradation by examining soil health under real‐world management practices. Soil health data from 5,300 field sites enrolled in a DNR cost‐share program were analyzed for the effects of tillage intensity [no‐till (NT), reduced tillage (RT), and intensive tillage (IT)] and crop rotational diversity (monoculture, two‐crops, and three or more crops in rotation) within and across six regions in the state. Soil health indicators included soil organic carbon (SOC), active carbon, potentially mineralizable nitrogen (PMN), and aggregate stability. At the state level, SOC, active carbon, and PMN were 14.4, 14.0, and 17.5% greater under NT, and 10.2, 11.0, and 11.2% greater under RT, respectively, compared with IT. Aggregate stability was greater under NT (33.8%) and RT (30.4%) relative to IT (28.0%). Across the state, diversified rotations with three or more crops exhibited 6.1 and 7.9% greater SOC, 6.5 and 7.9% greater active carbon, and 10.7 and 11.6% greater PMN relative to two‐crop rotations or monocultures, respectively. Aggregate stability was significantly greater under diversified rotations (35.5%) relative to two‐crop rotations (30.6%) and monoculture (30.8%). This study highlights the value of on‐farm datasets from real crop production systems and illustrates the potential to increase soil health with adoption of conservation tillage and extended crop rotations in Missouri.

Analysis of Long-Term Effect of Tillage Systems and Pre-Crop on Physicochemical Properties and Chemical Composition of Soil

The aim of the present study was to analyse the physicochemical properties and chemical composition of soil after years of applying varied tillage systems and pre-crops. The field experiments were carried out in Lipnik in Poland. The experiment was conducted over 25 years, with factor I–3 tillage systems: ploughing (A), ploughless (B) and direct sowing (C), factor II-pre-crop–1–faba bean, 2–sugar beet. Simplified tillage systems were used, and increased acidity was found in both layers due to lower pH, as well as an increase in exchangeable aluminum, hydrolytic acidity and exchangeable acidity of soil. The simplification of tillage system resulted in no significant effect on the following soil parameters: sum of base cations (TEB), cation exchange capacity (CEC) and electrical conductivity (EC). In both layers, there was a marked increase in the content of total nitrogen, carbon and available magnesium in soil with ploughless (B) and direct sowing (C) tillage systems. The change of the tillage system, which implied tillage reduction, was found to be the factor which has a significant effect on the physicochemical properties and chemical composition of soil. Tillage resulted a greater effect on the physicochemical properties, whereas pre-crop was found to affect the changes in chemical composition of soil to a greater extent. The results obtained in the research indicate that the tillage systems ploughless (B) and direct sowing (C) can be applied in practice.

Variation in Seed Yield, Oil Quality, and Seed Elements of Sunflower as Affected by Various Fertilizers and Tillage Systems

ABSTRACT This study was performed to investigate the effect of various fertilizers and tillage systems on seed yield, oil quality, and seed elements of sunflower (Shams cultivar). The experiment was conducted in a split-plot design with three replications at research field of University of Zabol (Chahnimeh) in 2019 and 2020. The main factor included three tillage methods (A1: moldboard plow + disc, A2: chisel plow + disc and A3: disc). Subfactor includes six fertilizer combinations :(B1: no fertilizer application, B2: 100 kg/ha of diammonium phosphate, B3: 25 tons/ha of livestock manure +100 kg/ha of diammonium phosphate, B4: 50 tons/ha of livestock manure +100 kg/ha of diammonium phosphate, B5: 25 tons/ha of livestock manure, B6: 50 tons/ha of livestock manure). Results showed that in the first year, the highest seed yield (5072 Kg/ha) and percentage of oleic acid (51.61%) was achieved from A3B6. In the second year, the highest seed yield (8003 Kg/ha) with A1B5 and the highest oleic acid (53.87%) was obtained from A2B2. Application of A2B2 treatment composition produced the highest nitrogen content in the seed (0.625%) and application of A3B6 produced the highest potassium content in the seed (11.652 mg/g). In general, by considering the reduction of tillage in the field and improving the traits of sunflower, the application of A3B6 is recommended to improve the percentage of oleic acid, phosphorus, and potassium contents and 1000-seed weight and if the conventional tillage is used, B2 can be recommended to improve seed yield, calcium content, and oil content.

Performance evaluation of infiltration models under different tillage operations in a tropical climate

Land management practices have the propensity to influence soil infiltration characteristics and predictability of infiltration models. This study was conducted to evaluate the performances of the Kostiakov model, the Philip model and the Horton model in predicting cumulative infiltration depth under four tillage systems in a sandy clay loam: (i) No Tillage (NT), (ii) Reduced Tillage (RT), (iii) Ploughing followed by Harrowing and Ridging (PHR), and (iv) Deep tillage followed by Ploughing, Harrowing and Ridging (DPHR). Using the double ring infiltrometer to measure the infiltration rate, the observed data was fitted to the infiltration models and their goodness of fit was verified by Root Mean Square Error (RMSE), Mean Absolute Error (MAE), coefficient of determination (R2), Nash Sutcliffe efficiency (NSE) and paired sample t-test. The results show that the Kostiakov model exhibited the highest accuracy with the highest R2 and NSE values (R2≥0.9967 and NSE ≥ 0.9965) and lowest errors (RMSE≤ 1.16 mm and MAE ≤ 0.98 mm). The comparison of the performances of the models in predicting the cumulative infiltration depth revealed that the Kostiakov model is superior to the Philip and the Horton models under all the Tillage systems, as the Philip and the Horton models underestimated and overestimated the observed data at the initial and latter parts of the experiment, respectively. The observed and predicted cumulative infiltration depth compared using the paired sample t-test showed that the Kostiakov model was better than the Horton and the Philip models under NT, RT and PHR, while the Horton model predicted better on the DPHR than the Kostiakov and the Philip models. The infiltration capacities of the conservation tillage practices (NT and RT) were higher than the conventional tillage conditions (PHR and DPHR). However, the performance of the evaluated models in predicting cumulative infiltration shows that the measured infiltration was best simulated for the DPHR followed by the PHR, RT and NT tillage practices. From our study the Kostiakov model precisely predicted the cumulative infiltration depth relative to the Horton and Philip models. It is, therefore, the preferred choice for modelling cumulative infiltration depth in the ochrosols of the study area and under verified field conditions, these models can be applied to determine the suitable infiltration characteristics to minimise deep percolation and run off losses in irrigation scheduling.

Long‐term tillage management affects claypan soil properties and soybean cyst nematode

AbstractUse of cover crops with conservation tillage systems can affect soil chemical and biological properties. The objectives of this research were to evaluate the effect of long‐term (1994–2016) no‐till (NT) and reduced‐till (RT) cropping systems on soil chemical properties and soybean cyst nematode (SCN, Heterodera glycines Ichinohe) egg population densities on claypan soils in northeast Missouri. Treatments included a corn (Zea mays L.)–soybean [Glycine max (L.) Merr.]–wheat (Triticum aestivum L.) rotation with three tillage–cropping systems: (a) NT corn–soybean–wheat with double‐crop soybean (NTDCS), (b) NT corn–soybean–wheat with frost‐seeded red clover (Trifolium pretense L.) cover crop (NTFSC), and (c) RT corn–soybean–wheat. Each crop (corn, soybean, and wheat) and tillage system (NTDCS, NTFSC, and RT) was represented every year in nine large plots and replicated four times. Soil was sampled to a 15 cm depth to evaluate soil chemical properties (1994, 2002–2016) and SCN egg densities (2002–2015). Soil test pHs, P, and K were ranked RT = NTDCS &gt; NTFSC, RT &gt; NTDCS = NTFSC and RT &gt; NTFSC &gt; NTDCS, respectively. Long‐term NTFSC cover crop had the greatest soil organic matter levels in four of the 16 yr. When combined over years, SCN egg densities were lowest in NTFSC following corn, soybean, or wheat, which indicates the benefit of NT and extended crop rotations to help manage this pest.

Fungal biomass and microbial necromass facilitate soil carbon sequestration and aggregate stability under different soil tillage intensities

The aim of global carbon (C) neutrality brings soils and their potential for C storage into the spotlight. Improved agricultural management techniques such as minimum or no-tillage are thought to foster soil C sequestration. However, the underlying mechanisms are still not well understood. In this study, we investigated the inter-relations of soil organic C (SOC), fungal biomass, microbial necromass biomarkers, and aggregate stability in rhizosphere and bulk soil after thirteen years of reduced tillage intensities (reduced, minimum, and no-tillage). Overall, rhizosphere and bulk soil were indifferent in their response to reduced tillage. Reducing tillage intensity increased SOC and nitrogen stocks and dissolved organic C contents in the following order: minimum > no-tillage > reduced > conventional. Aggregate stability showed the strongest increase under no-tillage. Interestingly, ergosterol contents were highest under reduced and minimum tillage followed by no-tillage. The amino sugars muramic acid, galactosamine, and glucosamine – proxies for soil microbial-derived necromass – showed similar increases under all three tillage reduction systems. Structural equation modelling revealed that increased dissolved organic C contents under reduced tillage intensity facilitated SOC sequestration and aggregate stability through enhanced fungal biomass to necromass turnover. Thus, reducing soil tillage intensity is a valuable tool to facilitate microbial growth and hence to increase SOC sequestration in agricultural soils.

Improved crop protection and biodiversity of the agroecosystem by reduced tillage in rice paddy fields in southern China

Agricultural sustainability has benefited from the broad adoption of conservation agriculture (CA) practices for decades, in which the reduction of mechanical disturbances to soil (also known as reduced tillage, RT) is one of the most essential principles for CA implementation. Many studies have recommended the advantages of CA practices in the promotion of biodiversity, but the integrated impacts on crop productivity and biodiversity remain unclear. Since CA has been applied in rice production in the subtropical area of southern China for several years, the effects of CA, particularly the RT methods, need to be evaluated for the local and long-term adoption. In this study, we established an integrated network to illustrate how the reduction of tillage intensity influenced organisms including invertebrates (such as rice pests and their predators), pathogens and weeds, and then led to an impact on rice yield. The two-year study demonstrated that major rice pests, such as rice planthoppers, stem borers and apple snails, were effectively controlled by RT practice. Similarly, the occurrence of common diseases declined with less tillage. Compared to the conventional tillage (CT) treatment, the density of weeds in paddy fields deceased significantly in the RT treatment. In addition, the diversity and richness of pest predators increased remarkably in paddy fields where either reduced or no tillage was applied, which highlighted the significance of a CA strategy for the promotion of biodiversity in the agroecosystem. More importantly, the rice yield gradually increased after the two-year reduction of tillage. Taken together, our results suggest that the reduction of tillage intensity is beneficial for the protection of rice crops from various pests, and facilitates the sustainability of the agroecosystem and rice yield, which provides a solid basis and novel insights for the establishment of sustainable agroecosystems by CA-related practices in rice production in southern China.

Fifteen years of conservation tillage increases soil aggregate stability by altering the contents and chemical composition of organic carbon fractions in Mollisols

AbstractMollisols contain a high amount of soil organic carbon (SOC) that is highly susceptible to tillage practices. Conservation tillage (CT) could improve soil aggregate stability, but the predominant factor controlling this stability remains debatable. This study reports on a tillage management experiment established in 2004 to explore the influences of tillage practices on the content and chemical composition of labile and recalcitrant OC fractions, plus with the aggregate stability change and potential mechanisms. CT without straw mulching, reduced tillage (RT), and no tillage (NT) (zero tillage) with straw mulching were set up. Compared with CT, 15‐year RT significantly increased SOC content (by 11.4%) in the surface (0–10 cm) by increasing the amount of aromatic compounds. Simultaneously, RT and NT promoted soil aggregate stability, as verified by the increase in mean weight diameter (MWD) and geometric mean diameter (GMD) of 7%–71.3% at 0–30 cm soil depth. Of importance, RT and NT increased aromatic compound amount of silt + clay fractions (by 12.6%–27.2%) within macroaggregates (&gt;0.25 mm) but decreased that (by 15.6%–32.9%) within free microaggregates (0.053–0.25 mm) than CT at 0–30 cm soil depth. Collectively, conservation tillage controls the SOC stability in Mollisols by regulating the MWD and GMD values and further affects the amount of aromatic compounds in silt + clay fractions within aggregates. Rather than physical and biochemical protection, chemical protection through a mineral association could be the crucial mechanism for aggregate stability under long‐term conservation tillage in Mollisols.

Conservation Agricultural Practices Impact on Soil Organic Carbon, Soil Aggregation and Greenhouse Gas Emission in a Vertisol

Conservation agriculture (CA), comprising of minimum soil disturbance and crop residue retention (&gt;30%), with a diversified cropping system, has become increasingly popular around the world. It is recognized as a sustainable practice to improve soil health by augmenting key soil properties. However, scanty information exists about the effect of CA practices on soil organic carbon (SOC), aggregation and greenhouse gas emissions (GHG) in a vertisol. Thus, this study investigated the effect of CA practices on SOC, soil aggregation and GHG emission under soybean-wheat and maize-chickpea cropping systems in a vertisol in Central India. Treatment consisted of three different tillage practices, being conventional tillage (CT), reduced tillage (RT), and no tillage (NT) under four cropping systems viz., Soybean–Wheat, Soybean + Pigeon pea (2:1), Maize–Chickpea and Maize + Pigeon pea (1:1). Regardless of cropping system, the soil under NT and RT exhibited better aggregation (20.77 to 25.97% increase), and SOC (12.9 to 19.4% increase) compared to the CT practice in surface layers. The aggregate-associated C concentration increased with aggregate size, and it was highest with large macroaggregates and lowest with silt and clay fractions across different tillage and cropping systems. Higher SOC stock was recorded under NT (4.22 ± 0.133 Mg C/ha) compared to RT (3.84 ± 0.123 Mg C/ha) and CT (3.65 ± 0.04 Mg C/ha) practices at 0 to 5 cm depth. Thus, the adoption of CA practices reduced CO2 emissions, while also contributing to increases in SOC as well as improvement in soil structure.

No tillage outperforms conventional tillage under arid conditions and following fertilization

Reduced tillage practices present a tool that could sustainably intensify agriculture. The existing literature, however, lacks a consensus on how and when reduced tillage practices should get implemented. We reanalyzed here an extensive dataset comparing how regular tillage practices (i.e., conventional tillage) impacted yield of eight crops compared to stopping tillage altogether (i.e., no-tillage practice). We observed that aridity and fertilization favored no tillage over conventional tillage whereas conventional tillage performed better under high fertility settings. We further show that the responses are consistent across the crops. Our reanalysis complements the original and fills a gap in the literature questioning the conditions under which reducing tillage presents a viable alternative to common tillage practices.

Evaluating Soil Conservation Effectiveness: An Investigation of Spatial Targeting, Conservation Adoption, and Financial Incentives

ABSTRACTIdentifying and treating erosion‐prone, critical source areas (CSA) presents the opportunity to effectively address erosion at a watershed scale. Social and financial drivers of conservation adoption, however have buffered implementation. An integrated systems understanding is needed to identify internal feedbacks and potential synergistic conservation policies. We simulate the physical, social, and financial incentive interactions with a high‐level system dynamics model to understand the conservation adoption and subsequent erosion behavior of the system. A Bass diffusion model integrated with physical modeling results enables the simulation of CSA, the diffusion of innovations, and payment for conservation practices. Land retirement and tillage reduction best management practices are assessed for the dryland wheat farming region in the Inland Pacific Northwest of the United States. Model utility was confirmed with quantitative land management data and qualitative local expertise. Historical, voluntary‐based efforts to reduce erosion suffer marginal returns. We conclude that: (1) All targeting of CSA reduces long‐term erosion rates; (2) The most effective use of conservation funds, however, occurs when the diffusion of innovation mechanism is reinforced by broad‐scale payments for tillage reduction; and (3) By identifying and utilizing positive feedback, our simulations suggest large gains in erosion reduction and conservation fund efficiency are possible.

Are No-Till Herbicide-Free Systems Possible? A Simulation Study

Conservation agriculture (CA) allows farmers to reduce costs and enhance soil health, but tends to increase weed infestation and associated crop yield loss, and/or herbicide use. We investigated how much tillage reduces weed infestation and yield loss, and which systems and weed species are the most affected by tillage suppression. We collected farming practices on 395 arable cropping systems mainly from France, and simulated them over 30 years and with 10 weather repetitions, using FlorSys. This process-based model simulates daily multi-species weed floras and crop canopies from cropping systems and pedoclimate over the years. Three series were simulated, (1) using the recorded systems, (2) eliminating tillage without any other changes, (3) eliminating herbicides without any other changes. Each series was run twice, once with a regional weed-flora pool to simulate weed dynamics and their impact on crop production and biodiversity, and once without weeds to predict potential crop yield. Among the recorded systems, herbicide treatment frequency index (HTFI) averaged over rotation increased when tillage frequency decreased. No recorded no-till system was herbicide-free. The untilled crops with the lowest HTFI (0.16) were unusual crops, i.e., relay grass-crops or multi-annual crops. Simulations of the recorded systems showed no correlation between tillage-frequency, and weed biomass or weed-caused yield loss. When tillage was deleted without any other change, yield loss almost doubled. We identified (1) which weed species and traits (e.g., spring annuals) increased after tillage suppression and in which cropping systems, (2) which recorded systems were robust to tillage suppression in terms of yield loss (with cover crops, summer crops, etc.), (3) which no-till systems (recorded or obtained after deleting tillage) limited yield loss (e.g., with frequent and/or efficient herbicides), (4) which management techniques were associated with a reduction in tillage, in herbicides, and in yield loss (long and diverse rotations, cover crops, etc.). No tested system achieved all three objectives simultaneously. The simulations indicated that two CA pillars (diverse crop rotations, cover cropping) were essential to manage weeds while reducing (or eliminating) both tillage and herbicide use. More no-till cropping systems must be investigated to determine whether sustainable no-till herbicide-free systems are possible.

Spring barley response to tillage systems and crop residues

The present study aimed to assess the effect of tillage systems and crop residues on grain yield and weed infestation of spring barley. The experiment was established with the method of randomized sub-blocks. The main experimental factor was the tillage system (TS): conventional tillage (CT), reduced tillage (RT), and no-tillage (NT). The second experimental factor included plots with crop residues (CR): straw (S) or without straw (WS). A higher grain yield of barley was determined in the RT than NT system. The RT system allowed producing a higher spike number and a higher 1000 grain weight. A higher grain yield was also obtained on the plots with straw (S) than without straw (WS). Greater weed density in barley stands was determined on RT and NT plots without crop residues (WS), whereas the lowest one was found on the CT plots with the residues (S). The air-dry weight of weeds was higher on the NT plots without crop residues (WS) than on the other plots, while the lowest air-dry weight of weeds was determined on the CT plots with the residues (S). The biodiversity of weeds in a barley stand was greater on the WS than on the S plots.

Soil respiration during three cropping cycles of durum wheat under different tillage conditions in a Mediterranean environment

AbstractThis study analysed respiration from soil cultivated with wheat under a Mediterranean climate and submitted to two tillage treatments: no tillage (NT) and reduced tillage (RT). Carbon dioxide (CO2) emissions were measured by static chambers in three growing seasons (2015–18) in the framework of a long‐term experiment of different tillage systems established in 2002. Tillage management remained the same throughout the trial, while chemical weed control was carried out in response to the actual weed content. Environmental variables were monitored, including the soil total organic carbon (TOC) content, water‐extractable organic carbon (WEOC), soil temperature and water content. Total CO2 emission, as mean of the studied seasons, did not significantly differ between NT and RT (2.35 and 2.24 t CO2‐C ha1 for NT and RT, respectively), although differences were found at the growth cycle scale. Total annual CO2 emission from NT was stable, being the same along the three cycles, while total RT CO2 emission decreased from the first to the third cycle. The TOC content was almost stable, while WEOC showed large variability that could explain the variability of CO2 emissions for RT over short time scales and was probably because of weed control in the middle of the second growing cycle. CO2 emissions were driven by soil water content via the impact on water filled pore space, and soil temperature range, that is daily maximum minus minimum temperature. In conclusion, for this winter wheat NT did not improve the balance of soil CO2 emissions with respect to RT.

Side Deep Fertilizing of Machine-Transplanted Rice to Guarantee Rice Yield in Conservation Tillage

Conservation tillage is an environmentally friendly and economical farming method, but its impact on rice yield is controversial. Artificially applied side deep fertilizing of machine-transplanted rice is when fertilizer is applied to the deep soil along with the machine transplantation of rice; this may improve the fertilizer utilization rate and rice yield and eliminate the possible negative effects of conservation tillage on rice yield. Using on machine-transplanted rice, this study aims to compare the effects of side deep fertilizing (SDF). We investigated the effects of artificially applying fertilizer (AAF) on rice growth and yield under conventional tillage (CT), reduced tillage (RT), and no tillage (NT). The rice root activity, root dry weight, leaf area index (LAI), net photosynthetic rate (Pn), chlorophyll content, panicle density, spikelets per panicle, and yield were all ranked as NT &gt; RT &gt; CT and SDF &gt; AAF. The 1000-grain weight was also ranked as SDF &gt; AAF. In addition, under NT conditions, the positive effect of SDF on rice growth and yield was higher than under RT and CT conditions. In general, conservation tillage combined with SDF saved costs and increased rice yield.

Effect of Different Tillage and Fertilization Interventions on Wheat (Triticum aestivum) Production

Wheat (Triticum aestivum) is considered the main aspect of food security in the Middle-East including Palestine. This important crop testifies a sharp decline in its productivity due to many reasons including climate change and its consequences in particular. This study was carried out in the eastern slopes of Bethlehem governorate that are classified as arid to semi-arid areas in the growing season 2018/2019. The experiment was laid out in a factorial randomized block design, for the aim of investigating the effect of different tillage (conventional tillage (CT) and three conservation tillage systems, reduced tillage (RT), conservation tillage at 8 cm (C8) and conservation tillage at 4 cm depth (C4)). In addition to their combination with different fertilization types (sheep manure (M), tri-superphosphate (TSP) and ammonium sulfate (AS) ) and ratios as the following (manure 6m³/dunum (M_6m³), manure 3m³/dunum+ TSP 6.25 kg/dunum+ AS 6.25 kg/dunum (M_3m³/TSP_6.25kg/AS_6.25kg), manure 3m³/dunum+ TSP 12.5 kg/dunum (M_3m³/TSP_12.5kg) and manure 3m³/dunum+ AS 12.5 kg/dunum (M_3m³/AS_12.5kg)) in addition to the control that was tilled without any fertilization treatments. Generally, our results revealed the superiority of the RT× M_6m³ in term of grain yield production. On the other hands, RT× M_3m³/TSP_12.5kg is recommended to increase straw production. This short- term study is definitely not sufficient to reveal the impact of the examined tillage and fertilization practices, but it gives indicators for the possible effects of these practices that need more investigation on longer term.

Tillage and nutrient management influence net global warming potential and greenhouse gas intensity in soybean-wheat cropping system

Conservation tillage has proven advantageous in improving soil health and productivity. However, the greenhouse gases (GHGs) emission and intensity from different conservation tillage and nutrient management systems under Indian conditions are less understood. Therefore, here, we compared the effect of tillage and nutrient management on GHGs emissions, net global warming potential (NGWP), and greenhouse gas intensity (GHGI) from a field experiment under five years in a soybean-wheat cropping system in the Vertisols. The tillage treatments comprised of reduced tillage (RT) and no tillage (NT). The three nutrient management treatments included application of 100% NPK (T1), 100% NPK + 1.0 Mg FYM-C ha-1 (T2), 100% NPK +2.0 Mg FYM-C ha-1 (T3). The results showed significantly higher SOC sequestration under NT (1388 kg ha-1 yr-1) followed byRT (1134 kg ha-1 yr-1) with application of FYM (2.0 Mg C ha-1) (T3) every year. Across tillage, integrated nutrient management(T2 and T3) lowered NGWP and GHGI compared to NPK (T1). The GHGI of NT system was less by 33% compared to RT. The results suggest that GHGs mitigation and sustained food production in the soybean-wheat system can be achieved in NT and RT with integrated use of organic and inorganic fertilizer as the major component of nutrient management.

Soil carbon and nitrous oxide dynamics in corn (Zea mays L.) production under different nitrogen, tillage and residue management practices

Reducing tillage frequency and intensity and returning crop residues to the soil are two agricultural management practices to increase soil organic carbon (SOC). Timing and rates of nitrogen fertilizer, coupled with tillage methods and residue incorporation, can also influence nitrous oxide emissions. In this study, we used measured data from a long term (23 years) tillage and residue management experiment, under intensive grain corn production, together with the DNDC (DeNitrification-DeComposition) process-based model, to ascertain the most effective fertilizer and tillage management practices to reduce nitrous oxide emissions and nitrate leaching, and increase soil carbon stocks. The field experiment consisted of no-till [NT], reduced [RT], and conventional tillage [CT], with and without corn residue return. After calibration and validation, using field observed data, the DNDC model was run with 108 management scenarios (six N application rates, spring single N fertilization, spring split N fertilization and fall fertilization, three tillage practices and two residue-return options). N application rate was predicted to be a significant driver for corn yield, SOC sequestration, N2O emissions and nitrate leaching, indicating the need to identify a critical N rate to both optimize production and achieve sustainability goals. Split (vs. single) N application did not significantly affect corn yield, nitrate leaching, N2O emissions or SOC, while fall fertilization should be avoided due to greater nitrate leaching and higher N2O emissions as well as lower crop yield. Although stimulating N2O emissions, both NT and residue return are recommended for their ability to enhance SOC stocks. Results of this study can be used for policy development regarding carbon sequestration and GHG emissions for intensive grain cropping systems in the humid regions of North America.