Conventional Tillage Systems Research Articles

Conservation Agriculture for Enhancing Crop Productivity, Energy Use Efficiency, Carbon Stock, Soil Health and Reducing GHG Emissions

ABSTRACT Conservation agriculture (CA) is believed to improve the soil properties. The question whether transplanted rice adapts to CA alike is not answered. Furthermore, the role of genotypes/varieties in CA is not clearly established. We compared two CA-based cropping systems i.e. ZT-direct seeded rice (DSR) followed by ZT-green gram (GG), (ZT-DSR-ZT-GG) and ZT-transplanted rice (TPR) followed by ZT-GG, (ZT-TPR-ZT-GG), vis-à-vis. conventional tillage (CT) system, (CT-DSR-CT-GG) with respect to soil structure, nutrient status, carbon sequestration potential, GHG emissions, energy saving and yield. Additionally, relative performance of green gram varieties under CA was evaluated. After five years, OC, N and P increased significantly in ZT-DSR-ZT-GG system. The increase in TOC was 16.90% and 11.86% in ZT-DSR-ZT-GG and ZT-TPR-ZT-GG, respectively, over CT-DSR-CT-GG. Similarly, in ZT-DSR-ZT-GG, the MBC, DHA, FDA, acid phosphatase and alkaline phosphatase were 2.7, 1.9, 1.4, 1.03 and 1.07 fold higher over CT-DSR-CT-GG. The cumulative seasonal emission of N2O was 73% and 35% higher in CT-DSR-CT-GG over ZT-DSR-ZT-GG and ZT-TPR-ZT-GG, respectively. Overall energy saving was 32% and 25% in ZT-TPR-ZT-GG and ZT-DSR-ZT-GG cropping systems, respectively, compared to CT-DSR-CT-GG. The system productivity was at par in CA (ZT-TPR-ZT-GG)- and CT-based cropping system. The interaction between the CA practices and the crop variety was non-significant for most of the tested parameters indicating flexibility in choosing a variety for crop cultivation under CA. It may be concluded that the associated benefits of CA without compromise in yield are highly recommended to sustain soil and environmental health in rice-pulse cropping system.

Effects of Conventional Tillage and No-Tillage Systems on Maize (Zea mays L.) Growth and Yield, Soil Structure, and Water in Loess Plateau of China: Field Experiment and Modeling Studies

Cropping system models can be useful tools for assessing tillage systems, which are both economically and environmentally viable. The objectives of this study were to evaluate the decision support system for agrotechnology transfer (DSSAT) CERES-Maize model’s ability to predict maize growth and yield, as well as soil water dynamics, and to apply the evaluated model to predict evapotranspiration processes under conventional tillage (CT) and no-tillage (NT) systems in a semi-arid loess plateau area of China from 2014 to 2016. The field experiment results showed that NT increased the surface soil bulk density and water-holding capacity but decreased the total porosity for the surface soil and the maize grain yield. Model calibration for maize cultivar was achieved using grain yield measurements from 2014 to 2016 for CT, and model evaluation was achieved using soil and crop measurements from both CT and NT for the same 3 yr period. Good agreement was reached for CT grain yields for model calibration (nRMSE = 4.02%; d = 0.87), indicating that the model was successfully calibrated. Overall, the results of model evaluation were acceptable, with good agreement for NT grain yields (nRMSE = 4.26%; d = 0.86); the agreement for LAI ranged from good to moderate (RMSE = 0.30‒0.31; d = 0.84‒0.85); the agreement for soil water content was good for NT (RMSE = 0.03‒0.08; d = 0.81‒0.95), but ranged from good to poor for CT (RMSE = 0.06‒0.09; d = 0.42‒0.88); the overall agreement between measured and simulated soil water varied from poor to good depending on soil depth and tillage. It was concluded that the DSSAT CERES-Maize model provided generally good-to-moderate simulations of continuous maize production (yield and LAI) for a short-term tillage experiment in the loess plateau, China, but generally good-to-poor simulations of soil water content.

Germination ecology of Chenopodium album L. and implications for weed management.

Chenopodium album L. is a troublesome annual species in various cropping systems, and a sound knowledge of the ecological response of C. album germination to environmental factors would suggest suitable management strategies for inhibiting its spread. Preliminary laboratory-based research was conducted to investigate germination and emergence requirements of C. album under various environmental conditions (e.g., photoperiods, constant temperature, salinity, moisture, soil pH, burial depth, and oat crop residue). Results showed C. album seeds were found to be photoblastic, with only 13% germination in darkness. The maximum germination (94%) of C. album occurred at an optimal temperature of 25°C, and the depressive effect of other temperatures on germination was more severe at lower rather than higher temperatures. Seed germination was suitably tolerant of salinity and osmotic potential, with germination observed at 200 mM NaCl (37.0%) and -0.8 MPa (20%), respectively. Germination was relatively uniform (88–92%) at pH levels ranging from 4 to 10. The maximum germination of C. album was observed on the soil surface, with no or rare emergence of seeds at a burial depth of 2 cm or under 7000 kg ha-1 oat straw cover, respectively. Information provided by this study will help to develop more sustainable and effective integrated weed management strategies for the control of C. album, including (i) a shallow-tillage procedures to bury weed seeds in conventional-tillage systems and (ii) oat residue retention or coverage on the soil surface in no-tillage systems.

Effect of Tillage Systems on Durum Wheat Production with Different Rotations in Semi Arid Area of Algeria

Background: Durum wheat is the most important cereal in Algeria. The yield of durum wheat is low and depends on climatic conditions and technical operations. Methods: The objective of this study is to compare the effect of the no-till system (NT) and conventional tillage system (CT) with three crop rotation sequences on wheat yield, yield components and some physiological traits under rain-fed conditions. The study was conducted at the technical institute of field crops-Sétif-in east of Algeria, over three crop seasons: 2016/17, 2017/18 and 2018/19. Result: The number of plants/m2, tillers/m2, spikes/m2​ and grain yield were affected by the tillage system and the environmental conditions. Seed weight, straw yield, biological yield, leaf relative water content and leaf chlorophyll content were significantly affected by the environment but not by the tillage system. While the spike density, the harvest index and the grain yield were significantly higher under NT system than in the CT system. Furthermore, wheat grain yield was also higher following legumes than in wheat monoculture. These results indicate that no-tillage and crop diversification by adding leguminous in rotation improves grain legumes yield of durum wheat under semi-arid conditions of Algeria.

SOIL ORGANIC MATTER, N AND P IN A SOIL CONSERVATION SYSTEM FOR ONION

ABSTRACT The objective of this study was to evaluate soil chemical attributes in a soil conservation experiment for onion, under different cropping systems. The study was conducted on a Humic Dystrudept in Ituporanga, Santa Catarina state, Brazil. Eight different cropping systems for onion were evaluated: T1: maize-onion succession, T2: common vetch-maize/rye+fodder raddish-onion-maize/rye+fodder raddish-common bean, T3: rye-onion-maize/black oat-maize, T4: onion-velvet bean succession, T5: rye-onion-millet/black oat-onion-millet, T6: rye-onion-velvet bean succession, T7: onion-velvet bean+millet+sunflower succession, from T1 to T7 were conducted under no tillage system (NTS), T8: maize-onion succession, was conducted under conventional tillage system. We used the randomized complete block design, with 5 replications. All the chemical samples were collected and evaluated at the 0-5, 5-10 and 10-20 cm soil layers, the soil chemical attributes evaluated as follows: total organic carbon (TOC), particulate organic carbon (POC), carbon associated to soil minerals (CASM), N and P. At the 0-5 cm layer, P concentrations were severely affected by the different cropping system. In terms of treatments similarities, the treatments may be grouped in three clusters as follows: cluster 1: T2, T3, T7, cluster 2: T1 and T8 and cluster 3: T4, T5, T6. For N concentration, the different cropping system affected its concentration at the 10-20 cm layer. Carbon associated to soil minerals wasn´t affected by the different cropping systems, indicating that more time is needed to study this soil organic carbon fraction. Keywords: crops rotation, nutrients, cover crops, clustering.

INFLUENCE OF AGRICULTURAL SYSTEM ON THE CONTROL OF BROMUS TECTORUM ON WINTER WHEAT

Bromus tectorum causes special problems because of its ability to reproduce through seeds and also because it’s relative tolerance to numerous herbicides. Extending new tillage systems, conservative systems specific to conservative sustainable agriculture, is a difficult task to accomplish under the circumstances of strong monocotyledonous weed infested Bromus tectorum is one of the most dangerous monocotyledonous weeds when applying unconventional system. A research was conducted in the pedoclimate condition of Agricultural Research and Development Station Turda, investigating the control of Bromus tectorum by conservative tillage. The goal was to determine the relationship between agricultural system and weeding degree on winter wheat. The use of minimum tillage and no tillage systems, caused at the end of a three year crop rotation, the increase of the Bromus tectorum pervasion in two systems, MD and NT. The occurrence of B. tectorum it is caused mainly due to the fact that the seeds are located in the first cm of the soil. Total weed density was significantly lower under the conventional tillage system (CS) and minim-chisel (MC) than under the minimum tillage-disk (MD) and no till (NT) system. The main benefit of the conventional tillage (CS) is a highly important decline of weeds.

Impact of the Cultivation System and Plant Cultivar on Arbuscular Mycorrhizal Fungi of Spelt (Triticum aestivum ssp. Spelta L.) in a Short-Term Monoculture.

Native communities of arbuscular mycorrhizal fungi (AMF) constitute a natural biofertilization, biocontrol, and bioprotection factor for most agricultural crops, including cereals. The present study investigated the native AMF population in cultivated spelt, i.e., a cereal that has not been analyzed in this respect to date. In particular, the aim of the study was to determine the number of spores and the degree of AMF root colonization in two spelt cultivars (Franckenkorn and Badengold) from a 3-year monoculture grown in two different cultivation systems: conventional tillage and no-tillage systems. The study showed considerable accumulation of AMF spores in the soil (on average 1325 in 100 g of air-dry soil), with a wide range of their numbers, and not a very high degree of endomycorrhizal colonization (on average from 3.0% to 31%). The intensity of AMF growth in the subsequent cultivation years gradually increased and depended on the cultivation system as well as the growth stage and cultivar of the spelt. It was found that both analyzed AMF growth indices in the no-tillage system were positively correlated with each other. Moreover, their values were higher in the no-tillage system than in the conventional system, with statistical significance only for the number of spores. This was mainly observed in the variant with the Franckenkorn cultivar. The effect of the growing season was evident in both cultivation systems and spelt cultivars. It was reflected by intensification of sporulation and mycorrhization of spelt roots by AMF in summer (maturation stage) compared with the spring period (flowering stage).

Effects of Conservation and Conventional Tillage on some Soil Hydraulic Properties

The aim of the study is to compare the effects of both conservation tillage and conventional tillage on soil physical properties, such as soil water content, soil porosity, bulk density, and soil organic matter. The majority of farmers in Iraq apply conventional tillage for grain production, by using different types plow for land preparation before planting, which increases the cost of production. On the other hand, some farmers use conservation tillage as known as no-tillage system that involves the cultivation without tillage, the only soil disturbance being during the planting time. The research was conducted in Erbil Agriculture Research Directorate for planting bread wheat for three growing seasons (2017 – 2018), (2018 – 2019), (2019-2020) and (2020 – 2021). The land was divided into two parts, the first part was planted with no-tillage tillage, and the second part was planted with conventional tillage by using chisel plow and disk plow before planting. The results indicated that the soil physical properties and soil organic matter were influenced by tillage system. There are no significant differences between both tillage systems on soil moisture content from the sowing time until eight weeks of planting. However, no-tillage system has higher soil moisture content after eight weeks of sowing until flowering stage at 10cm depth. The no-tillage system decreases of soil bulk density and increases soil porosity and soil organic matter compared to conventional tillage system.

Physical fractions of organic matter and mineralizable soil carbon as quality indicators in areas under different forms of use in the Cerrado-Pantanal Ecotone

Understanding soil organic matter (SOM) dynamics is essential to employ management that contribute to the improvement of soil quality (SQ). The aim of this study was to characterize the SOM and evaluate the emission of mineralizable C (C-CO2) in different management systems. The soil was collected in five managed areas: exposed soil (ES), conventional tillage system (CTS), no-tillage system (NTS), permanent pasture (PP) and sugarcane (SC), in addition to a forest area (NF), in the layers of 0-5, 5-10, and 10-20cm. Total organic carbon (TOC), physical-granulometric fractionation of SOM were performed, determining the contents and stocks of particulate organic matter (C-POM; StockPOM) and mineral organic matter (C-MOM; StockMOM), in addition to calculating SQ indices. In addition to C-CO2 emissions from the soil. The areas of PP and NTS presented the highest levels of TOC in the surface layer. The highest levels of C-MOM and StockMOM were observed in the PP area, besides higher CSI (carbon stock index), reaching 1.67 in the 10-20cm layer. The areas of PP and SC were similar to the NF in all layers regarding CMI (carbon management index). In CTS, there were higher peaks in emissions and accumulation of C-CO2. It is evident that the improvements in the SQ in the areas of PP, SC, and NTS caused mainly by the deposition of plant material and by soil revolving not being performed. In the CTS, high emission peaks of C-CO2 show that the lack of conservation management practices contributes to the emission of greenhouse gases.

Tobacco harvest phase is critical to runoff and soil loss in conventional tillage system

AbstractSoil erosion in tobacco (Nicotiana tabacum) cultivation has been reported in recent years around the world. Moreover, studies also demonstrated total soil loss during cultivation. In this study, we proposed an assessment of loss of water and soil during the phases of tobacco cultivation. The tobacco cultivation cycle is approximately 180 days in Southern Brazil. We divided this period into 6 phases from planting (September) to the end of the harvest. During the phases, there were variations in soil management, which may indicate different rates of water and soil loss. Gerlach gutters were used to mediate soil and water loss. At each phase of cultivation, we also measured the surface roughness of the soil, water retention, soil exposure, trampling, soil resistance and soil bulk. Our results show that during cultivation the water and soil loss were 10.2% and 62.7 Mg ha−1, respectively. However, the variation of activities during tobacco cultivation indicates different rates of water and soil loss. In the first three phases (90 days after planting), the surface roughness remained high (~19.2%) due to the soil turning, thus reducing the loss of water and soil despite little ground surface coverage. The soil tillage is stopped when the harvest of tobacco begins 120 days after planting. During the harvest, there was an increase in daily activities in the tobacco field, as the leaves were harvested every week, thus reducing soil roughness (~6.8%) and increasing soil density and strength. These conditions increased the rate of soil erosion during harvest. Therefore, the harvest phase is critical to runoff and soil loss.

Energy budgeting and carbon footprint of contrasting tillage and residue management scenarios in rice-wheat cropping system

Puddled transplanted rice followed by conventional till wheat, the most predominant cropping system in South Asia is unsustainable, highly energy intensive and leads to significant carbon equivalent emissions. Conservation agriculture (CA) practices like zero till dry direct seeded rice, zero till wheat, residue retention and diversified crop rotations have potential to improve productivity and reduce energy and carbon footprints. Therefore, we evaluated the energy and carbon relationships in rice-wheat cropping system under contrasting tillage and residue management scenarios with the aim to promote sustainable and energy efficient CA systems with lower C footprint. Treatments comprised of zero till dry direct seeded rice – zero till wheat (~double zero till) and zero till dry direct seeded rice – zero till wheat – zero till mungbean (~triple zero till) systems, with and without residue retention of preceding crop. Besides, conventional till (CT) rice (i.e. puddled transplanted rice) – CT wheat system (~CTRW), and conventional till rice – zero till wheat system were adopted as farmers’ practice control. Two-year pooled results highlighted that the zero till (ZT) systems led to consumption of substantially lower operational energy for land preparation (100 %), sowing (34–50 %) and irrigation (24–36 %) than conventional till system. The zero till direct seeded rice + mungbean residue – zero till wheat + rice residue – zero till mungbean + wheat residue system (~ZTRWMb+R) registered ~5 % lower rice yield but 16 % and 23 % higher wheat grain yield and system biomass yield, respectively over CTRW. This system incurred highest total input energy (157.4 × 103 MJ ha−1), having ~64 % of this energy shared from renewable crop residue, but had highest (11.3) energy use efficiency from non-renewable resources (fuel, fertilizers, machinery). In contrast, the zero till direct seeded rice – zero till wheat – zero till mungbean system without residue resulted in highest net energy returns, energy ratio, energy productivity and energy intensity. The ZTRWMb+R system led to 64 % lower yield scale C footprint (304 kg CO2-eq. t−1) compared to CTRW (848 kg CO2-eq. t−1) and had highest C efficiency, C sustainability index and C efficiency ratio. Selection/development of high yielding and biotic (mainly, nematodes) and abiotic (mainly, Fe deficiency) stress tolerant varieties for direct seeded rice would help reduce/bridge the yield gap with puddled transplanted rice and further enhance crop and biomass yields and energy productivity of CA based rice-wheat cropping system.

Soil Management, Irrigation and Fertilisation Strategies for N2O Emissions Mitigation in Mediterranean Agricultural Systems

Feeding a growing population, which will reach 10 billion in 2050, is a major challenge. Another major challenge is to increase crops’ productivity in a sustainable way, as the increase in agricultural inputs may lead to greenhouse gas emissions, including N2O fertiliser. Several factors can influence N2O emissions such as irrigation, the soil management system, or the type of fertiliser used. The aim of this research is to study the impact of each above-mentioned factor on N2O emissions during three growing seasons in a maize field, considering three nitrogen fertilisers: urea (U), ammonium nitrate (AN), and a fertiliser with the nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP); two irrigation strategies: on demand (100%) and deficit irrigation (75% of demand); and a comparison of two soil management systems: conventional tillage (T) systems and no-tillage (NT) system. The interactions among the three factors and their effects on emissions were analysed through a principal component analysis. Higher emissions were recorded in plots that received the highest irrigation dose. The most favourable management to reduce N2O emissions derived from agricultural activity for maize crops under a Mediterranean climate was the NT soil management, using a fertiliser with nitrification inhibitor and an irrigation dose of 75% of conventional irrigation.

Soil quality indicators in conventional and conservation tillage systems in the Brazilian Cerrado

Conventional and conservation tillage systems can alter soil aggregation and total and labile soil organic matter (SOM) contents. This study aimed to determine the degree of soil aggregation, quantify total carbon (TC), permanganate oxidizable carbon (POXC), light organic matter (LOM), and potentially mineralizable carbon (CO2-C) contents in soils aggregates, and assess soil quality indexes at sites under conventional and conservation tillage in the Cerrado region of Minas Gerais State, Brazil. Four experimental areas were analyzed: a area under conventional tillage for 20 years, a area under no-till for 6 years, a area under no-till for 18 years, and a reference area of undisturbed Cerrado vegetation. Soil aggregates retained on 8.0–4.0 mm sieves were evaluated for size class distribution and mean weight diameter. TC, POXC, LOM, daily and Total CO2-C emissions were also analyzed. These data were used to calculate the C/N ratio and sensitivity, carbon pool, and lability indexes. The results of SOM compartments were in agreement with those obtained for the soil aggregation status. 6NT and 18NT had a higher proportion of macroaggregates and higher MWD values than CT in both layers. For other classes of aggregates, CT had the highest proportions of mesoaggregates at 0–0.05 m depth and microaggregates at 0–0.10 m depth. At 0–0.05 m depth, TC and LOM contents were highest in 6NT and 18NT aggregates. In comparing the soil indexes of managed areas, we found a similar pattern to that observed for macroaggregates, MWD, TC, and LOM. CA, 6NT, and 18NT aggregates had the largest CO2-C cumulative emissions at the end of the incubation period. Environmental conditions at no-till areas promoted macroaggregate formation and preserved TC and LOM contents, resulting in a high degree of aggregate stability. Soil quality indexes were sensitive to identify changes between the reference area and managed areas. Soil aggregates from no-till areas had higher CO2-C emissions and cumulative emissions than those from the conventional tillage area.

Impact of Tillage and Phosphorus Application on Agronomic Efficiency of Maize (Zea mays L.) in the Eastern Part of DRC

There is limited information on the impact of tillage and Phosphorus application on Phosphorus Agronomic efficiency of maize and, the implication for crop yield on different soil types in the Eastern part of DRC. To bridge this gap in knowledge, a study was undertaken in the major rainy season of 2018 on an Orthi-Ferric Acrisol at Walungu and Rhodic Lixisol at Mulungu in the Easter montain of DRC. The experiment was laid out in a split-plot design with four replications for both locations. There were two variants for the tillage factor: conventional tillage (CT) and no-tillage (NT) systems and four phosphorus application rates: 0, 30, 60 and 90 kg P2O5 in the form of triple superphosphate (TSP) designated as P0, P30, P60 and P90, with basal applications of nitrogen and potassium at the rates of 90 kg N ha-1 and 60 kg K2O ha-1. Phosphorus use efficiency indices such as partial factor productivity (PFP) and agronomic efficiency (PAE) were evaluated. The results showed tillage to generally influence P use efficiency of maize in both experimental sites at harvesting with good values for CT. Phosphorus was efficiently utilized by the maize crops at on both soils. Significant tillage x phosphorus interactions (p<0.05) were recorded among treatment combinations with regards to PFP and PAE at both Walungu and Kabare Though CTP60 Kabare recorded the highest grain yield comparable to that of CTP60 at Walungu. Although its limitation in most of tropical soil, Phosphorus can be used efficiently under valuable tillage systems for sustainable crop production in this area.

Deep tilling and localized liming improve soil chemical fertility and sugarcane yield in clayey soils

The selection of an appropriate soil tillage system for improving yields and longevity is an important decision in sugarcane cultivation. In the present study, the effects of different soil tillage systems and methods of applying lime on sugarcane stalk and sugar yield performance as well as soil fertility parameters were evaluated throughout the sugarcane crop cycle. The experiments were established in two locations in April 2015 and conducted until August 2019, corresponding to a total of 4 growing seasons. A field study with a randomized block design was established with four replicates considering 4 treatments: conventional soil tillage system (CT), deep strip-tillage system (DT) and modified deep strip-tillage system (MDT), all with the same lime rate; and a standard treatment (control, CT without liming). Immediately after harvesting plant cane (18 months (mo) after planting), first ratoon (30 mo after planting), second ratoon (42 mo after planting) and third ratoon (54 mo after planting), soil samples were collected from a depth of 0.0–1.00 m, stratified every 0.2 m. Leaf material was sampled during the period of full vegetative growth. Analyses of soil chemical fertility, leaf concentrations of elements, and sugarcane yield components were performed. MDT was found to correct soil acidity most efficiently, mainly due to the positioning of the lime application. Under high aluminum saturation (AS), especially in deeper layers, deep lime placement was more effective and resulted in the best distributions of calcium (Ca2+) and magnesium (Mg2+), the highest base saturation (BS) and the lowest AS compared with the other treatments. Lime application was more important than the tillage system for improving the sucrose concertation and total recoverable sugar (TRS), whereas the tillage system affected the stalk yield and, consequently, the yield of sugar. Compared with DT and CT, the average stalk yield was 4.1% and 9.4% higher, respectively, under MDT at Macatuba and 6.3% and 15.3%, higher, respectively, under MDT at Piraju. Similarly, MDT improved average sugar yield by 3.7% and 10.4% at Macatuba and 6.1% and 16.3% at Piraju. Overall, long-term assessments, which are important for semi-perennial crops like sugarcane, showed that the both deep strip-tillage were most effective.

Agronomic Performance of Rainfed Barley Genotypes under Different Tillage Systems in Highland Areas of Dryland Conditions

Conservation agriculture (CA) is becoming increasingly attractive to farmers due to advantages such as lower production costs and less destruction of soil structures compared to the conventional tillage. The cultivars introduced for the conventional systems may not be suitable under CA environments, and newly adapted cultivars need to be developed. Accordingly, four separate field experiments were conducted over two cropping seasons (2018–2019 and 2019–2020) to study the agronomic performance of seven barley genotypes under three tillage systems: conventional tillage (full tillage with residue removed), reduced tillage (chisel plowing with residue retained) and CA system (no tillage with residue retained on soil surface). The genotypes were grown under rainfed conditions in two different agro-ecological regions (Kamyaran and Hosseinabad locations) in the west of Iran. Significant genotypic differences were observed for grain yield and yield components except 1000-kernel weight. The results of this study showed that rainfed barley genotypes under a CA system produced yields equal to, or better (0.7%) than, the conventional tillage; while reduced tillage system decreased their performance by 4.9%. Regarding genotype × tillage interaction, the barley genotypes Catalhuyuk 2001 and Bulbule positively interacted with conventional tillage and showed higher performance than other genotypes, whereas genotypes Çumra 2001, Ansar and Abidar expressed highest performance under CA system. Consequently, genotypes Bulbule, Catalhuyuk 2001 and Gumharriyet 50 outperformed the domestic performance and the amount of grain yield and showed the highest adaptation to the tested environments. The results of the present study could be useful to improve the efficiency of a CA system in rainfed cultivation of barley and open new windows for the cereal production in arid and semi-arid regions with food security concerns.

The Yield and Weed Infestation of Winter Oilseed Rape (Brassica napus L. ssp. oleifera Metzg) in Two Tillage Systems

Results from a four-year field experiment were used to evaluate the effect of conventional tillage (CT) and no-tillage (NT) systems on the yield, selected yield and crop structure elements, weed infestation, and contents of fat and glucosinolates in the seeds of winter oilseed rape (Brassica napus L. ssp. oleifera Metzg). The study proved the beneficial effect of the NT system on the winter rape seed yield only during the precipitation shortage in the growing season. In the years with a sufficient sum of precipitation, a higher seed yield was produced in the CT than in the NT system. Considering the average values from the four-year study period, the seed yield and straw yield, plant density after emergence and before harvest, number of branches and main shoot length, and finally the 1000 seed weight were significantly higher in the CT compared with the NT system. In contrast, the NT system proved more beneficial regarding seed weight per silique and fat content of the seeds. The statistical analysis of the study results showed no effect of the tillage systems on the glucosinolate content of the seeds. In turn, a significantly higher number and air-dry weight of weeds as well as an increased density of Viola arvensis weeds were demonstrated in the NT plot compared with the CT plot of winter oilseed rape. Sonchus asper and Sonchus arvensis were identified in the NT plot but not in the CT plot. A significantly higher density of Chenopodium album and Euphorbia helioscopia weeds was detected in the CT system compared with the NT system. The statistical analysis of study results regarding weed community diversity showed similar values to the Shannon-Weinner diversity index (H’) in both tillage systems and a significantly higher value of the Simpson dominance index (SI) in the NT system compared with the CT system.

Stubble Quality of Wheat Grown under No-Tillage and Conventional Tillage Systems, and Effects of Stubble on the Fermentation Profile of Grazing Ewes’ Ruminal Fluid

Conservation practices that involve leaving mulch on the soil are known to increase soil fertility. However, mulch is an important source of feed for ruminant livestock. Accordingly, the trade-offs between mulching and stubble uptake by livestock are currently hot topics in the research field. In this study, a comparison between the quality of stubbles of wheat grown in no-tillage and conventional tillage fields and the rumen fermentation characteristics of Barbarine ewes grazing in the two fields was carried out. Samples were collected four times after wheat grain harvesting. Immediately after harvest, stubble biomass was slightly higher under no-tillage than conventional tillage. The ewes displayed different grazing behavior, with feeding at a higher rate on the conservative stubble than the conventional stubble. This feeding behavior seemed to be an adaptive strategy to offset the decline in the nutritional quality of stubbles from no-tillage-grown wheat. Indeed, dry matter, protein, fiber, and ash contents were lower in stubbles from no-tillage than conventional tillage at the second sampling time. Consequently, the concentration of the volatile fatty acid, propionic acid, was lower in ewes grazing in the conservative plots. However, this feeding behavior did not cause any body weight impairment during the two-month experimental period. At the end of grazing, the no-tillage practice was found to be comparable to the conventional tillage system according to the amount of residue remaining on the soil surface. Therefore, no-tillage could not be used to solve the competition between crops and livestock for residues.

Sustainability assessment of corn production in conventional and conservation tillage systems

To develop sustainable cropping systems, the coherence between economic, environmental, and energy aspects must be considered. We aimed to assess the sustainability of corn (Zea mays) production using four tillage systems which varied in the intensity of soil disturbance (i.e., conventional till with moldboard plow (MP), conventional till with chisel plow (CP), strip-tillage (ST), and no-till (NT)) by performing life cycle assessment (LCA) analysis and Material Flow Cost Accounting (MFCA). It is common that material and energy wastage is not considered in sustainability assessment studies. When material and energy wastes are calculated in monetary terms, the hidden costs of production will be revealed. Simultaneous application of LCA and MFCA methods in sustainability assessments can provide such valuable information. Cradle-to-farm gate was considered as the system boundary in LCA-MFCA. The total annual energy input for corn production using MP, CP, ST, and NT was found to be 37472 MJ ha−1 (3092 MJ t−1), 36384 MJ ha−1 (3290 MJ t−1), 33717 MJ ha−1 (3309 MJ t−1), and 32889 MJ ha−1 (2764 MJ t−1), respectively. As energy demand increased, yield per ha also increased in all tillage systems except in NT in which yield increase was concurrent with improved energy efficiency. The gross value was calculated as 1470 $ ha−1 (121 $ t−1) for MP, 1446 $ ha−1 (131 $ t−1) for CP, 1380 $ ha−1 (128 $ t−1) for ST, and 1334 $ ha−1 (112 $ t−1) for NT system. The economic indices for each tillage system were computed. Our results showed that eliminating those negative products in corn production can increase farmers' net benefit by 200 $ ha−1. Global warming potential, acidification potential, eutrophication potential, ozone depletion potential, and photochemical ozone creation were selected to reflect the environmental impact associated with corn production in each tillage system. From an environmental standpoint, NT and MP performed much better than CP and ST. In three important impact categories (i.e., global warming potential, acidification, and eutrophication potential) MP, and in the other two impact categories (i.e., photochemical ozone creation potential and ozone depletion potential) NT system performed best among all tillage systems. It can be concluded that NT showed the best performance in terms of energy, economic and environmental indicators for corn production followed by MP system.

Clean weeding showed positive effects on earthworm communities following six years of minimum tillage in a maize field in northern Zimbabwe

ABSTRACT Earthworms are a major component of soil fauna communities with positive effects on soil chemical, biological and physical processes. A study was carried out to investigate the medium-term effects of cultural practices on earthworm communities in an agricultural field. Data were collected in the 2018/2019 cropping season from a six-year-old experiment with tillage system, fertiliser application rate and weeding intensity as the main, sub- and sub-subplots, respectively. Lumbricus (34.4%) and Diplocardia (38.3%) were the dominant genera, while endogeic earthworms (48.4%) dominated the community structure among other earthworm functional groups. Clean weeded plots under the basin planting system had higher Lumbricus abundance (quadruple), genus richness (76.4%) and Shannon diversity index (56.0%) than all other treatments. Inorganic fertiliser application in the conventional tillage system reduced Eisenia abundance and genus evenness by 100.0% and 73.3%, respectively. These results suggest that in minimum tillage systems, frequent hand weeding confers positive effects on earthworms including increased abundance. In conventional tillage systems, application of high doses of inorganic fertiliser is detrimental to earthworm communities. Further studies need to focus on identifying the most sustainable and cost-effective hand weeding frequency for enhanced earthworm diversity and increased crop productivity.