Conventional Tillage Practices Research Articles

Sunflower Growth Performance under Tillage or No Tillage Practice, Irrigation Intervals and Nitrogen Fertilization Rates

Growth expressions of sunflower, supplied with 30, 45, and 60 kg N/ fad, were examined under the treatment of two tillage practices (conventional tillage and no tillage applications) and three irrigation intervals (12, 18 and 24 days, between each two successive irrigations) during 2017 and 2018 summer seasons at the Experimental Farm of the Itay-EL-Baroud Agricultural Research Station. Responses of plant height, leaf area index, flowering date, stem diameter, head diameter, 1000-seed weight, seed yield/ fad., harvest index and seed oil content in addition to oil yield/ fad. were significant having the maximum records for sunflower with 12 days interval of irrigation. Also, the highest values of plant height, leaf area index, harvest index, seed yield/ plant, during the two seasons, and seed yield /fad, oil yield (in 2017) and 1000-seed weight (in 2018) were achieved with conventional tillage compared to no tillage. Meanwhile, no significant effects were obtained for flowering date, stem diameter and head diameter during the two seasons of study, and 1000-seed weight (in 2017), seed yield and oil yield/ fad (in 2018) based on tillage practice. Increasing the level of nitrogen fertilization up to 60 kg/ fad, significantly increased all studied characters except nitrogen use efficiency (NUE) and oil percent which decreased with increasing nitrogen levels during the two seasons. The interaction of irrigation intervals and tillage practice significantly affected plant height over the two seasons. This trait had maximum values with the shortest irrigation interval (every 12 days) and 60 kg N/ fad. The obtained data indicated that 1000-seed weight, seed yield/plant, leaf area index and harvest index were significantly affected by the irrigation interval and nitrogen levels interaction. Meanwhile, high seed and oil yields were achieved with short interval (every 12 days) under conventional tillage and nitrogen levels of 40 and 60 kg N/ fad. It is recommended to grow sunflower under conventional tillage practice, with applying irrigation every 12 to 18 days and nitrogen fertilizer at the rate of 45 to 60 kg N/ fad, to obtain highest seed and oil yields.

English

Maize is one of the major staple foods in Uganda, providing over 40% of Uganda’s daily calorie consumption. Tillage practice is one of the crucial factors that influence crop productivity through maintenance of soil health. The aim of this study therefore is to validate the effect of tillage practice on the vegetative growth and yield of maize in Uganda. The trial was established on-station at Ngetta Zonal Agricultural Research and Development Institute, Lira district and on-farm in Njeru Town Council, Buikwe district. It was laid out in a factorial design with two tillage practices (conventional tillage, CT and minimum tillage, MT) as the main factors and two maize varieties (Longe 10H and Longe 5) as the levels. The results showed significant differences in plant height between the two tillage methods (p< 0.001). Conventional tillage practice had a higher mean maize grain yield per hectare compared to minimum tillage although the difference was insignificant (p<0.332). Thus, the adoption of minimum tillage practice by farmers in Uganda would require investment in organic herbicides in order to control the weeds sustainably and boost maize productivity. Key words: Conventional tillage, minimum tillage, vegetative growth, yield, maize. &nbsp

Post-Rainy Season Pigeonpea Holds Promise for the Diversification of Cropping Systems

The temporal and spatial intensity of rainfall in north-east plains (Central and Eastern Uttar Pradesh, Bihar, Jharkhand, West Bengal, Assom and North-Eastern states) often leads to temporary waterlogging, causing partial to complete mortality of pigeonpea seedlings during rainy season. Post-rainy season (September) plantings may be adopted as an alternate approach to address the issue of waterlogging and crop diversification. Research conducted at the ICAR-RCER, Patna has shown that sowing of ‘Pusa 9’ during second week of September after harvest of quality protein green cob maize provided up to 3.0 t/ha grain yield under zero tillage with optimum crop management practices (one hand weeding, one-two insecticide spray of imidacloroprid @1mL/L water at 10 days’ interval commencing from second fortnight of February). Similarly, ‘IPA 203’ sown on September 20, 2018 yielded more than 3.0 t/ha under conventional tillage practices (N: P: K: 20:50:0; two hand weeding; one irrigation during second fortnight of December and two spray of the same insecticide at the same interval). These findings indicate that the system is agronomically feasible, economically highly remunerative and ecologically sustainable to bring about diversification in upland ecology of north-east plains of India.

The wind erodibility in the newly emerged surfaces of Urmia Playa Lake and adjacent agricultural lands and its determining factors

Despite the great extent of Urmia Playa Lake (UPL), researchers have rarely ever studied the development of playa surfaces and their vulnerability to dust emission. Therefore, we aimed the current research to study the formation of UPL surfaces and how their physicochemical, mineralogical and geomorphological characteristics affect their susceptibility to wind erosion. An area of 41 km2 was chosen including lands from UPL and adjacent Agricultural Lands (AL). Different playa surfaces were identified on different geomorphic surfaces and mapped using Landsat images. Later, 75 soil samples from depth of 0–5 cm of different map units were collected and subjected to physicochemical analysis. Soil Erodible Fraction (EF) was also measured as an index for the wind erodibility of the examined soil surfaces. X-Ray Diffraction (XRD) and X-Ray Fluorescence (XRF) analysis of soil samples from three playa surfaces with significantly different EF values were also conducted. Major reasons for the development of different playa surfaces were found to be basically related to geomorphic surfaces on which they have developed, size and mineralogical composition of the sediments as well as the landscape position and depth to the groundwater. Statistical analysis of EF of different playa surfaces and AL showed that Salt Crusts (SC) had the lowest mean EF value due to the formation of a thin layer of salt on its surface as it has developed on low stand geomorphic surface being fine-textured by nature and rich in Na, Mg and Cl ions. Abandoned Agricultural lands (AA) and AL had the highest mean EF values. High sand content of soils with anthropogenic origin along with conventional tillage practices resulting in soil organic matter loss and over grazing were the major reasons of their high EF. Therefore, these surfaces need to be monitored carefully and to be of high priority of conservation and dust control programs in the region.

Soil quality and carbon sequestration under conservation agriculture with balanced nutrition in intensive cereal-based system

Conventional tillage practices and imbalanced use of inorganic fertilizers is well known to result in poor soil health. Alternative tillage and precision nutrient management are important strategies for tackling the issues of soil health deterioration, particularly in cereal-based intensive cropping systems. Therefore, we conducted a 4-year study with the objective of (a) monitoring the changes in soil physical, biological and chemical properties and crop productivity, (b) development of soil quality index-SQI, and monitor its’ changes against system productivity as management goal, and (c) studying the changes in soil organic carbon-SOC in relation to annual C input. The experiment was laid out in a split-plot design with 3-tillage practices [zero tillage-ZT; permanent beds-PB; and conventional tillage-CT] and 4-nutrient management strategies [Control (unfertilized), farmers’ fertilizer practice-FFP, recommended fertilizers doses-Ad-hoc and site specific nutrient management-SSNM] under a continuous maize (Zea mays L.) - wheat (Triticum aestivum L.)- mungbean (Vigna radiata L. Wilczek) rotation in a sandy loam soil (Typic Haplustept) of north-western Indo-Gangetic plains (NW-IGP) of India. The ZT/PB with SSNM/Ad-hoc nutrient management resulted in higher values of a) physical parameters viz., water stable aggregates >250 μm, saturated hydraulic conductivity (Ksat) and mean weight diameter-MWD, b) chemical parameters viz., SOC, available N, P, and K, and c) biological parameters viz., microbial biomass carbon and enzyme activities (fluorescein diacetate hydrolase, dehydrogenase, ß-glucosidase and alkaline phosphatase) compared with CT and unfertilized treatments. The CA practices recorded an increase in WSA (12–21%), MWD (14–29%), and Ksat (11–14%) compared with CT at the 0-0.15 m and 0.15–0.30 m soil depths, respectively. The PB-SSNM registered (44.1%) higher SOC content as compared to CT-unfertilized plots. Values for MBC, FDA and βGA declined in the order SSNM=Ad-hoc>FFP > Control. While, the DHA declined in the order SSNM>Ad-hoc=FFP > Control. Principal component analysis included MWD, SOC and available K in the minimum data set (MDS) as the soil quality indicators. Adoption of PB/ZT resulted ∼22.5% higher SQI compared with CT. The SSNM plots improved SQI by ∼19.3% and ∼5.3% over unfertilized and FFP. The SSNM based CA practices attained a significantly higher annual C sequestration rate than other treatments. Therefore, adoption of CA with SSNM and Ad-hoc nutrient management in intensive cereal based systems of NW-IGP is essential for improving nutrient cycling, soil quality, crop productivity and C-sequestration potential.

A review of soil carbon dynamics resulting from agricultural practices

Literature related to the carbon cycle and climate contains contradictory results with regard to whether agricultural practices increase or mitigate emission of greenhouse gases (GHGs). One opinion is that anthropogenic activities have distinct carbon footprints – measured as total emissions of GHGs resulting from an activity, in this case, “agricultural operations”. In contrast, it is argued that agriculture potentially serves to mitigate GHGs emissions when the best management practices are implemented. We review the literature on agricultural carbon footprints in the context of agricultural practices including soil, water and nutrient management. It has been reported that the management practices that enhance soil organic carbon (SOC) in arid and semi-arid areas include conversion of conventional tillage practices to conservation tillage approaches. We found that agricultural management in arid and semi-arid regions, which have specific characteristics related to high temperatures and low rainfall conditions, requires different practices for maintenance and restoration of SOC and for control of soil erosion compared to those used in Mediterranean, tropical regions. We recommend that in order to meet the global climate targets, quantification of net global warming potential of agricultural practices requires precise estimates of local, regional and global carbon budgets. We have conducted and present a case study for observing the development of deep soil carbon profile resulting from a 10-year wheat-cotton and wheat-maize rotation on semi-arid lands. Results showed that no tillage with mulch application had 14% (37.2 vs 43.3 Mg ha−1) higher SOC stocks in comparison to conventional tillage with mulch application. By implementing no tillage in conjunction with mulch application, lower carbon losses from soil can mitigate the risks associated with global warming. Therefore, it is necessary to reconsider agricultural practices and soil erosion after a land-use change when calculating global carbon footprints.

Conservation agriculture as a climate change mitigation strategy in Zimbabwe

ABSTRACT There is a need to quantify agriculture’s potential to sequester carbon (C) to inform global approaches aimed at mitigating climate change effects. Many factors including climate, crop, soil management practices, and soil type can influence the contribution of agriculture to the global carbon cycle. The objective of this study was to investigate the C sequestration potential of conservation agriculture (CA) (defined by minimal soil disturbance, maintaining permanent soil cover, and crop rotations). This study used micrometeorological methods to measure carbon dioxide (CO2) flux from several alternative CA practices in Harare, central Zimbabwe. Micrometeorological methods can detect differences in total CO2 emissions of agricultural management practices; our results show that CA practices produce less CO2 emissions. Over three years of measurement, the mean and standard error (SE) of CO2 emissions for the plot with the most consistent CA practices was 0.564 ± 0.0122 g CO2 m−2 h−1, significantly less than 0.928 ± 0.00859 g CO2 m−2 h−1 for the conventional tillage practice. Overall CA practices of no-till with the use of cover crops produced fewer CO2 emissions than conventional tillage and fallow.

Changes in soil organic carbon fractions and residence time five years after implementing conventional and conservation tillage practices

Tillage not only affects the quantity of soil organic carbon, SOC, but also its quality. Therefore, an investigation was conducted to see how a five-year (2011–2016) implementation of conventional tillage, CT, and conservation tillage practices, CTP’s, under dryland vetch – wheat farming system can affect the total organic carbon, TOC, of soil and its fractions as well as its biological indicators including the half-life of organic materials, HL, and the mean residence time, MRT. The applied tillage practices included three CTP’s of reduced tillage, RT, with chisel plow, minimum tillage, MT, with stubble cultivator, and no-tillage, NT, with direct seeding as well as one conventional tillage, CT, with moldboard plow. The results revealed that all applied CTP’s (RT, MT, and NT) significantly increased the TOC of examined surface soils (0−25 cm) compared to CT. The labile fraction of SOC (dissolve organic carbon, DOC) under CTP’s, excluding NT, showed a significant decrease compared to CT. While MT significantly increased the fraction of organic carbon stabilized by clay and silt particles, OC{c + s} compared to CT, NT and RT made no considerable change in OC{c + s} compared to CT. There was also a considerable (but insignificant) increase in the amount of organic carbon stabilized by sand and aggregates plus particulate organic matter, OC{S + A+POM}, under CTP’s compared to CT. We recorded the greatest (228 ± 21 μg N g−1 2 h−1) and least (98 ± 27 μg N g−1 2 h−1) activity of urease under RT and CT systems, respectively, and the differences were significant. Based on the incubation data, the NT and RT systems significantly resulted in highest HL, (170 ± 9 days) for soil organic materials while CT had the lowest HL, (127 ± 5 days). While RT showed significantly the highest aggregate stability (55 ± 7 %), the CT and MT had the lowest aggregate stability (29 ± 4 %). In general, our results demonstrated the benefits of CTP’s, and more specifically the benefits of RT and NT systems, in improving SOC, as primary indicator of soil quality, in surface soils under dryland agriculture in terms of quantity and quality of organic carbon.

Experimental Evaluation for the Impacts of Conservation Agriculture with Drip Irrigation on Crop Coefficient and Soil Properties in the Sub-Humid Ethiopian Highlands

A field experiment consists of conservation agriculture (CA) and conventional tillage (CT) practices were set up in two areas, Robit and Dangishta, in sub-humid Ethiopian highlands. Irrigation water use, soil moisture, and agronomic data were monitored, and laboratory testing was conducted for soil samples, which were collected from 0 to 40 cm depth before planting and after harvest during the study period of 2015–2017. Calculation of crop coefficient (Kc) revealed a significant decrease in Kc values under CA as compared to CT. The result depicted that CA with a drip irrigation system significantly (α = 0.05) reduced Kc values of crops as compared to CT. Specifically, 20% reductions were observed for onion, cabbage, and garlic under CA whereas 10% reductions were observed for pepper throughout the crop base period. Consequently, irrigation water measurement showed that about 18% to 28% of a significant irrigation water savings were observed for the range of vegetables under CA as compared to CT. On the other hand, the results of soil measurement showed the CA practice significantly (α = 0.05) increased soil moisture (4%, 7%, 8%, and 10% increment for onion, cabbage, garlic, pepper) than CT practice even if irrigation input was small in CA practice. In addition, CA was found to improve the soil physico-chemical properties with significant improvement on organic matter (10%), field capacity (4%), and total nitrogen (10%) in the Dangishta experimental site. CA with drip irrigation is evidenced to be an efficient water-saving technology while improving soil properties to support sustainable intensification in the region.

Tillage and cropping effects on soil organic carbon: Biodegradation and storage in density and size fractions

AbstractImprovements in management practices can prevent the decline of soil organic carbon (SOC) storage caused by conventional tillage practice in Northeast China. Density and size fractionation can track the transformation of plant residue into SOC and its location in the soil matrix. We used a long‐term field study in China to evaluate these changes as a result of improved management involving tillage and cropping systems. Experimental treatments included no‐till (NT) and mouldboard ploughing (MP) under monoculture maize (Zea mays L.) (MM) and maize‐soybean (Glycine max Merr.) rotation (MS); these were compared to the traditional management involving conventional tillage (CT) under MM. An incubation study was conducted to evaluate mineralization and the biodegradability of SOC. The soils were also physically fractionated by density (light fraction, LF) and size (sand, silt and clay). With improved management, the SOC storage in the clay size fraction showed the largest increase across all fractions. This increase was greater for MS than MM. The NTMS treatment resulted in a decline in silt‐OC storage compared to CTMM. The SOC mineralization (mg CO2‐C g−1 soil) was affected by tillage and driven by LF‐OC and was observed in the order: NTMM (2.06) > MPMM (1.72) ≈ NTMS (1.71) > CTMM (1.52) ≈ MPMS (1.41). Both cropping and depth affected the biodegradability of SOC. Considering the plough layer (0–20 cm), treatments under MM had a larger proportion of biodegradable SOC than those under MS. We conclude that the significant differences in SOC storage in physical fractions and SOC biodegradation were caused by differences in soil management.Highlights Clay size fraction showed the largest increase in SOC storage when residue was returned. Silt size fraction lost SOC in no‐till maize‐soybean compared with traditional farming practice. Potential SOC mineralization depended on quantity of SOC in the LF. Biodegradability of the SOC was driven by cropping system not tillage.

The influence of the soil management systems on aboveground and seed bank weed communities in olive orchards

AbstractThe biodiversity of farmed landscapes is, in the context of agricultural intensification, a key aspect with regard to improving the sustainability of agroecosystems. Olive groves are undergoing rapid changes because of the spread of intensive farming systems, which may have negative environmental impacts. This paper reports a survey on the aboveground flora and seed banks in five olive groves located in Andalusia (Southern Spain). In this study, the following three management systems have been compared: no‐tillage, with the mowing of spontaneous weedy vegetation; no‐tillage, with the mowing of planted cover crops (Poaceae); and conventional tillage practices. Results showed that coverage and an abundance of vegetation are favored by spontaneous weedy vegetation with mowing management, while the richness of aboveground species was affected by landscape diversity and the presence of edges, which increases the richness and diversity of aboveground flora species in olive groves. Seed bank composition showed a low relationship with aboveground flora in the three cover crop management systems. The multivariate analysis performed pointed to those seed species that have a major influence on the aboveground flora communities of each of the three agricultural systems. The seed bank was clearly impoverished in terms of both abundance and species richness after the long‐term conventional tillage practices. We conclude that the intensive long‐term conventional tillage dramatically reduces weed communities in olive orchards and the subsequent ecosystem services provided by them.

Assessing the Impacts of Tillage and Mulch on Soil Erosion and Corn Yield

Conventional tillage practices have been regarded as the major reason for the loss of fertile topsoil in the sloping agricultural lands of the middle hills of Nepal. Reports on the effects of no-till and mulch on soil and corn yield in these regions are scarce, although these farming practices have been recommended to reduce soil erosion and increase crop yields. To assess the impacts of tillage (with +T, without −T) and mulch (with +M, without −M) on soil and soil nutrient losses, and corn yield, we conducted an experiment with five treatments: −T+M, −T−M, +T+M, +T−M, and bare fallow (BF), replicated four times each in an unbalanced complete random block design in Salyan district of Nepal. The results showed the presence of corn and no-till significantly lowered the soil losses. Losses of soil organic matter (SOM) and total nitrogen were also significantly reduced by the presence of corn, no-till, and mulch. However, no effects of mulch on soil losses, and no effects of tillage, mulch and corn on soil phosphorus losses were observed. Soil loss was found to be significantly and positively correlated with total seasonal rainfall, monsoon being the most severe season for soil erosion. While no-till and mulch did not affect corn height, cob height, and stover yield, no-till significantly increased the corn yield by 0.52 Mg ha−1 compared to conventional till. We confirm the synergistic interaction of mulch with tillage to reduce the losses of SOM and total nitrogen, and effectiveness of no-till to reduce the soil losses and increase the corn yield in the middle hills of Nepal. As this study is based on the results of two year’s data, long-term studies are required to identify the long-term impacts of no-till and mulch on soil losses and corn yield across the country.

Effects of Genetically Modified (GM) Maize Adoption in Small Scale Farms on Cropping Systems of the Eastern Cape Province, South Africa

Genetically modified (GM) crops are being promoted to ensure agricultural productivity and food security to keep pace with the ever-growing global population and food demand. In as much as agricultural technological advancements are crucial, there is need to strike a balance with agrobiodiversity for sustainable farming. Surveys were conducted in five municipal districts of the Eastern Cape Province to determine GM-technology adoption effects on maize cropping systems, agronomic practices and farmers’ perceptions of production constraints. Interviews of 232 farmers, independent (IF) 22.4% and government sponsored (GCP) 77.6%, revealed a wide variation in agronomic practices amongst them. Results indicate significant differences on the maize cropping systems practiced by the Eastern Cape small scale farmers. The majority (81.7%) of interviewed small scale GCP farmers produce maize as a monocrop, under dryland (91.7%) through conventional tillage practices (100%). In contrast, IF farmers practiced maize sole cropping (34.6%), under dryland (90.4%) through conventional tillage practices (86.5%). There were significant differences between the two farmers’ groups on crop mixture used (p=0.00), crop rotations (p=0.02), choice of maize varieties (p=0.00) and fertiliser use (p=0.00). Demographic and farm characteristics, type of land cultivation, production constraints, pest problems and pest management practices are discussed. The findings suggest the need to devise a system that will improve compatibility of GM-maize technology and traditional farming practices to ensure sustainable farming and food security for the resource poor farmers. The government support schemes seeking to enhance agricultural productivity need to equip farmers with the necessary versatile farming skills.

Conservation agriculture with drip irrigation: Effects on soil quality and crop yield in sub-Saharan Africa

The traditional agriculture production system in sub-Saharan Africa (SSA) caused significant soil erosion and degradation of soil quality. In addition, dependability of rainfall for irrigation needs limits the crop production. Advanced agricultural practices are thus needed at the local level to sustain the livelihood of smallholder farmers in the region. In this study, conservation agriculture (CA) practice with drip irrigation technology was compared (using field experiments and watershed modeling) with the traditional conventional tillage (CT) practice for its potential in improving soil quality and crop productivity in the region. Biophysical data were collected (2015 to 2017) from a total of 43 paired plots (CA and CT) at four study sites in SSA: Dangishita and Robit in Ethiopia, Yemu in Ghana, and Mkindo in Tanzania. The Agricultural Policy/Environmental eXtender (APEX) model was calibrated and validated with reasonable efficiency in simulating crop yields for both CA and CT practices; average PBIAS ≤±12% and ≤±11%, for CA and CT. The impact of the CA system on soil quality (soil carbon [C] and nitrogen [N]) was analyzed based on the well-tested model prediction results. The total C and N were increased under CA across the study sites on average by 6% and 4.1%, when compared to CT over the study period. Both the experiment and model prediction showed that crop yield was significantly improved by CA—on average 37.4% increases across the sites when compared to CT. Conservation agriculture with drip irrigation was an efficient local strategy to improve crop production in the region while enhancing the ecosystem.

Short-term effect of soil tillage and NPK fertilization rates on soil carbon sequestration and yield of Colocasia esculenta Schott in two micro-environments in SE, Nigeria

Quantification of soil organic carbon cycling as impacted by soil and crop man- agement practices is required for C storage and soil quality improvement investi- gations. This study assessed the short-term effect of conventional tillage (CT) and No-Tillage (NT) practices on SOC sequestration and yield of cocoyam (Colocasia esculenta). The experiment was conducted simultaneously at two lo- cations (06◦52' N, 07◦15' E and 06◦ 26' N; 07◦16' E) in southeast Nigeria. A Ran- domized Complete Block Design with five replications and four treatments com- prised of CT and NT, respectively, with 150 and 300 Kg ha-1 of NPK 15:15:15, was used. Soil quality attributes were measured at two soil depths (0-20 cm and 20-40 cm) in both locations and analyzed. The results indicated that the quantity of carbon sequestered in the soil at 0-20 cm soil depth for both sites was 46.7- 90.9 and 65.0-117.9 Mg ha-1, respectively, for the two planting seasons in NT plots treated with 300 Kg ha-1 of NPK. This was followed by NT plots treated with 150 Kg ha-1 of NPK, which sequestered 55.5-86.2 and 46.7-91.9 Mg ha-1 SOC. CT plots that received 300 Kg ha-1 NPK with 11.3-47.6 Mg/ha SOC had 44% and 28% lower stored SOC when compared to NT, NPK 150 Kg ha-1 plots for the two-planting season respectively. This indicates that CT practices signifi- cantly limit SOC sequestration. CT with 300 Kg of NPK 15:15:15 gave the high- est corm yield, followed by No-till with 300 Kg ha-1. A better edaphic condition provided by CT was compensated for by higher doses of N fertilizer in NT Plots.

Peanut residues supply minimal plant‐available nitrogen on a major soil series in the USA peanut basin

AbstractField observations have shown that a substantial portion of peanut leaves abscise in windrows during pod curing, leading to an uneven distribution of leaves and stems when intact residues are spread during harvest. Possible differences in nitrogen (N) mineralization rates between peanut leaf and stem residues may lead to spatial and temporal variability in available N during subsequent crops. The objective of this study was to quantify N mineralization in soil amended with different peanut residue components under simulated conventional and conservation tillage practices. A 252‐day microlysimeter incubation was conducted in which peanut leaves, stems and a 1:1 mixture of leaves:stems from three varieties were incorporated or placed on the soil surface to simulate conventional or conservation tillage, respectively. Soils were periodically leached to assess N mineralization compared with a soil‐only control. Nitrogen mineralization was only affected by residue component. Averaged over variety and residue placement, soil amended with leaves mineralized 10% more N relative to the control or soil containing stems. It was estimated that leaves supplied 25 kg N ha−1 over 252 days at 0–15 cm soil depth, which would likely be insufficient to induce a yield response by a subsequent crop. This study suggests that uneven distribution of peanut leaf and stem residues following harvest causes only minor spatial and temporal variability in available N during subsequent crop growth. These results support the growing body of evidence indicating that peanut residue N contributions to subsequent crops are negligible in the peanut basin of the south‐eastern USA.

Forage and maize yields in mixed crop-livestock farming systems: Enhancing forage and maize yields in mixed crop-livestock systems under conservation agriculture in sub-humid Zimbabwe

In mixed crop-livestock farming systems, smallholder farmers face the challenge of insufficient dry season livestock feed whilst crop production is mainly constrained by poor soil fertility and erratic rains. Conservation agriculture (CA) which is premised on three main principles namely minimal soil disturbance, crop rotations and mulching is being promoted as a potential solution to declining soil productivity. However, farmers implementing CA in mixed crop-livestock systems are conflicted by the use of crop residues either as livestock feed or as mulch under crop production. A study was carried from 2012/13 to 2014/15 season in Murehwa, a sub-humid region of Zimbabwe, to evaluate the effects of maize-legume cropping systems on forage, maize grain yield and gross margins. In this context, forage refers to the plant material/biomass harvested for livestock feeding. The cropping systems involved one conventional tillage practice with continuous sole maize (CT), four CA treatments consisting of continuous sole maize, maize-mucuna intercrop, maize-cowpea intercrop and maize-groundnut/soybean rotations. The experiment was replicated on eight farmers’ fields with each farmer treated as a replicate. Maize-mucuna (4 134 kg ha-1) and maize-cowpea (3 999 kg ha-1) intercrop systems significantly increased forage yield compared to CA sole maize (3 646 kg ha-1) and CT sole maize (3 076 kg ha-1). Among the rotations, maize-soybean rotation system performed better than the maize-groundnut system with respect to forage yield and maize grain. Intercropping and sole cropping systems however showed no significant maize grain yield difference. The highest and lowest gross margins/ha were obtained from the maize-mucuna intercrop (US$1395) and maize-soybean rotation system (US$507), respectively. The study thus suggests that farmers can grow legumes as intercrops with maize without any loss in maize grain yield. Maize-mucuna intercropping was the best of the tested cropping systems with respect to forage yield and gross margins in mixed crop-livestock systems of Murehwa.

Estimating risk premiums for adopting no-till and cover crops management practices in soybean production system using stochastic efficiency approach

Several alternative conservation practices that address farmers' concerns over natural resource stewardship are currently available. Such conservation practices as the planting of cover crops and conservation tillage are some of the most widely promoted practices throughout the U.S. today. Based on three-years (2016–2018) of field data and historical market price, crop yield, crop price, and fuel and fertilizer price are simulated to create net return distributions. To evaluate the profitability of conservation alternatives and the risk efficiency of these alternatives, the stochastic efficiency with respect to a function (SERF) method is used for analyzing the no-till and cover crop management systems in Louisiana soybean production. SERF estimates certainty equivalents (CE) in order to rank a set of risk-efficient alternatives over a range of risk aversion preferences. Results indicate that CE values are higher for conventional tillage practices than for no-till and risk premiums are positive across all risk-aversion values; however, for risk-averse farmers, premiums are almost zero if their current system is either a no-till or conventional tillage system where the farmer has already implemented a cover crop.

Conservation Agriculture and Maize Production Risk: The Case of Mozambique Smallholders

Farming systems in southern Africa are characterized by substantial exposure to external risks to crop production. Compounding these external risks are the effects of climate change, soil degradation, and soil fertility decline that mandates developing sustainable intensification practices to address these issues. In 17 target communities of central Mozambique from 2008–2011, we evaluated the performance of conservation agriculture practices (CAPs) to assess the risk perceptions of smallholder farmers regarding these technologies. The study used the results from 638 farms representing three agro‐ecological regions. Net returns were generated for each practice and compared using non‐parametric procedures. Risk‐preferred technologies were identified using mean‐variance, stochastic dominance, and stochastic efficiency with respect to risk function criterion. The results suggest that maize yields were higher for the CAPs systems at low and high elevation sites as compared with conventional tillage practices. Yield variability was also lower in higher elevation areas. At higher elevations, direct seeding was risk‐preferred, ranking higher by risk‐averse farmers than conventional tillage practices. Risk preferences were ambiguous at lower elevations. However, defining producer utility with a power utility function allowed for comparisons of the technologies over a range of risk‐aversion levels. At intermediate and higher altitudes, the direct seeding technology dominated the basin and conventional tillage practices. In low altitudes, and assuming producers were extremely risk‐averse, the conventional practice might be preferred over CAP technologies. These findings have implications with respect to selecting areas where CAPs are known to out‐perform conventional tillage systems before outscaling technology transfer programs to smallholders.Core Ideas Four‐year on‐farm experiments were conducted on 638 smallholder farms in Mozambique. The field treatments compared yields from conservation agriculture and conventional tillage systems. Net returns from each system were compared to conventional farmer tillage practices. The analysis identified risk‐preferred technologies. The conservation agriculture system was preferred by risk‐averse producers farming at higher elevations.

Ridge formation with strip tillage alleviates excess moisture stress for drought-tolerant crops

The impact of climate change is expected to be more severe in semi-arid and arid ecosystems. Seasonal and high-rainfall floods have recently become a common occurrence in semi-arid sub-Saharan countries in southwestern Africa, where ridging is becoming an important method to alleviate flooding stress in drought-tolerant crops. The objective of this study was to propose a feasible tillage method and compare its agronomical effects to those of conventional tillage practices in northern Namibia in sub-Saharan Africa. Pearl millet and cowpea were grown in the field using different tillage methods in seasonal wetlands in this area. We investigated crop yield, growth parameters, soil moisture content, and the shape of the ridge. Soil tillage using a newly proposed disc ridger for two-wheel tractors resulted in higher yield and growth rate in both crops than using the other tillage methods i.e. single mouldboard ploughing with animals and/or disc harrowing with four-wheel tractor. Ridge formation with strip tillage (partial pulverization) using the disc ridger resulted in significantly lower soil moisture content after irrigation because of the higher aspect ratio of the ridge. It is likely that large undisturbed portion remained therewith prevented the ridge from collapsing because of the irrigation water that imitated natural rainfall in this region. Therefore, ridge formation with strip tillage leads to good drainage, and as a result, proper drying of soil prevents flooding stresses thus enhancing early growth and yield of pearl millet and cowpea.