Although cassava (Manihot esculenta Crantz) is regarded as an important food and energy crop, the effects of its cultivation on greenhouse gas (GHG) emissions remain poorly documented. This study, conducted in a tropical red Oxisol in Cambodia, quantified the effects of long-term cassava-based cropping systems on soil methane (CH4) and nitrous oxide (N2O) emissions using static chambers over two years (2022-24). Also accounting for measured change in soil organic carbon (SOC) stocks, the greenhouse gas balance (in CO2-eq) of the systems was determined. Established in 2009, the replicated treatments included: (1) conventional tillage mono-cropping cassava (CTM-Cs), (2) no-till mono-cropping cassava with biomass retention (NTM-Cs), and (3) no-till bi-annual cassava-maize rotation with cover crops (NTR), where cassava (Cs) and maize (Mz) are grown in two separate plots: NTR1 and NTR2. CH4-C emissions ranged from -123 to +141 & micro;g CH4-C m(-2) hr(-1), with negligible cumulative emissions (-1.76 to +0.94 kg CH4-C ha(-1) yr(-1)), depending on cropping systems and season. In cassava treatments, N2O-N emissions peaked after mineral fertilizer application (up to +141 & micro;g N2O-N m(-2) hr(-1)), while maize treatment showed the higher peaks (up to +437.18 & micro;g N2O-N m(-2) hr(-1)) after cover crop termination under NTR. Cassava treatments had lower (p < 0.05) average cumulative N2O-N emissions (0.74-0.87 kg N2O-N ha(-1) yr(-1)) than maize (1.42 kg N2O-N ha(-1) yr(-1)). With similar yield-scaled CH4 and N2O emissions, cassava yield under NTR-Cs was 20-30% higher (p > 0.05) than CTM-Cs and NTM-Cs, respectively. Accounting for CH4 and N2O emissions and annual SOC accumulation, NTM-Cs, NTR1 and NTR2 systems (2022-24) resulted in a net climate mitigation benefit by sequestering -3.52, -1.93 and -3.16 Mg CO2-eq ha(-1) yr(-1), respectively. Our results showed that while N2O emissions were consistently higher in the treatment characterized by greater cover crop residue quantity and quality, they only slightly offset the climate benefits due to increased SOC stocks. Overall, the findings underscore the potential of NT systems for sustainable cassava production and climate change mitigation.

In Cambodia, vegetable crops are planted by hand, making it hard to meet local market demands. However, this production can be boosted by using a mechanical transplanter with two-wheel tractors to cut input costs, when introduced to farmers, while production and productivity can be accelerated. Thus, this research aimed to (1) evaluate the working performance of a locally made vegetable transplanter against manual planting and (2) compare plant survival rates. The study included fabrication, testing, modification, and experiments with farmers, starting from January 2023 to July 2024. The transplanter was fabricated, tested, and improved by the Royal University of Agriculture. Then, two experiments were carried out with a vegetable farming community in Tram Kak District, Takeo Province, Cambodia. Tomato was selected for the testing, choosing seedlings aged four weeks. The randomized complete block design (RCBD) was applied for both experiments with two treatments, manual planting and transplanter use, replicated four times. The results show that the working performance of the transplanter was six times faster than manual planting. Its speed, total field capacity, and planting rate were 1.03 km/h, 0.052 ha/h, and 27 plants/min, respectively, but missed planting was about 4%. Within-row spacing was similar (0.58 m), while using the transplanter made the plants incline at a steeper angle (63°), but could save 81.9% of time, when compared to manual planting. Both treatments had 100% plant survival rates evaluated one week after the transplanting. In short, using the transplanter can save both time and labor, but further assessment should be made with more kinds of fruit vegetable based on different seedling ages, so that the specifications can be confirmed, which is good for actual adoption for farmers.

Purpose The purpose of this study was to examine rural school students’ perception of a career in farming following their participation in educational farming activities.Design/Methodology/Approach We hypothesized that engagement with innovative educational farming activities can influence young people’s aspirations for a career in farming and that this relationship is mediated by relatedness to the local environment, and agriculture’s perceived impact. A survey instrument was administered, and mediation was examined using path analysis.Findings Significant direct and indirect effects were observed indicating that engagement with educational agricultural activities significantly influences students’ relatedness to their local environment, and their perceptions toward agriculture’s impact on their local community, which in turn has a positive effect on their attitudes toward a career in farming.Theoretical Implication The results of this study point to the generalizability of Social Cognitive Career Theory (SCCT) across contexts and provide empirical support for its suitability in analyzing different approaches to attract and retain youth in the agriculture sector in Cambodia.Practical Implication The results highlight the benefits of providing contextually-appropriate educational programs that are designed to reframe agriculture as innovative, profitable, and interesting to encourage youth to consider a future career in the sector.Originality/Value The findings can guide future training agendas and agricultural educational programs to be more efficient in attracting and retaining youth in the sector by incorporating contextually-appropriate educational topics that highlight agriculture’s impact and strengthen youth relatedness to their local environment.

Irrigation is widely considered a potential means to improve agricultural productivity, nutrition, and income, as farmers can carry out farming and production year-round. However, the feasibility of irrigation technologies is highly dependent on the long-term economic return farmers achieve. Solar-based irrigation could address the challenges of underinvestment in irrigation within Africa. Evidence on the economic viability of the adopted solar pumps such as MajiPump is very scant and focused on ex post evaluation. This study evaluated the income and nutritional feasibility of solar-powered irrigation using the MajiPump in sub-humid Ethiopian highlands using the farm simulation (FARMSIM) model and compared it with the manual pulley system. Results from the FARMSIM model show that farmers’ adoption of Maji solar pump technology to grow vegetables is economically feasible with financial support such as credit or loan for initial and capital investment to acquire the pump. The average profit under the solar MajiPump, drip irrigation, and conservation agriculture was 3.6 times higher than that of the baseline scenario. While the pulley technology provides the same amount of irrigation water to grow vegetables, its feasibility is limited due to high labor costs and time, estimated to be more than seven times the baseline. The simulation results show that the alternative scenarios’ nutrition level has improved relative to other scenarios and met the minimum daily average nutrition requirement level for proteins, iron, and vitamin A but fell short in fat, calcium, and calories. The results suggest that farmers who adopt improved small-scale irrigation technologies (solar MajiPump and drip system) have a higher potential to increase production and income from irrigated crops and improve their nutrition if part of the income generated is used to purchase supplemental food for their nutrition.

Study region: Robit Bata and Dengeshita watersheds, Upper Blue Nile basin, Ethiopia Study focus: Sustainable development of groundwater in the Ethiopian Highlands requires recharge measurements. The Water Table Fluctuation (WTF) method has been used to measure recharge. Lateral flow in sloping hillside aquifers violates the assumptions on which the original WTF method is based. We modified the original WTF method to include lateral flow controlled by gravity. New hydrological insights: Previously it was shown that the sum of recharge over the travel time in a sloping aquifer is equal to the base flow. Since recharge cannot be measured directly, the recharge calculated with the modified WTF method was tested using baseflow measurement in two contrasting highland watersheds, Robit Bata and Dengeshita, where groundwater depth and streamflow data were monitored from 2015 to 2018. Baseflow was determined with the oneparameter digital filter technique. Predicted and observed monthly baseflow agreed well with R-2 > 0.9 and RMSE < 20 mm during calibration and validation. Recharge in Robit Bata, in which the aquifer underlays 55% of the watershed, was 293 mm a 1 of 1378 mm a(-1) precipitation. In Dengeshita, where the entire watershed has an aquifer, the average annual recharge was 525 mm a(-1) of 1550 mm a(-1). Our findings indicate that the modified WTF method is simple and practical for determining aquifer recharge for highlands and other sloping aquifers.

Soybean (Glycine max [L.] Merr) is an important crop, as both food for humans and feed for livestock in Cambodia, but the yields are low, due to use of low yielding genotypes and limited use of inputs. This study aimed to investigate the effects of different genotypes and different N and P fertilizer sources on growth, seed yield, and seed protein of soybean. Five genotypes (Sbung, Hongry, 98C81, ACS1, and Kaiabi) were grown under different N (90 kg N ha−1 from urea, nano-n, Nitroplus, and without N application as control) and P fertilizers (50 kg P ha−1 from Inorganic P, nano-p, Mykovam, and without P application as control) in two screenhouse experiments. Shoot, root, and nodulation traits, as well as seed yield and protein, were significantly affected by genotypes and different N and/or P fertilizer sources. Notably, while genotypes Sbung and 98C81 showed the highest yields among the genotypes, regardless of different N and P fertilizers, only Sbung had the highest seed protein. The application of different N and/or P sources significantly increased seed yield, compared to non-N and -P application. Specifically, seed yield and seed protein were higher when treated with nano-n or urea, and number of nodules, root biomass, and nodule dry weight was increased with Nitroplus, whereas seed yield and protein were higher with nano-p, Mykovam, and inorganic P. Application rate of 90 kg N ha−1 and 50 kg P ha−1 produced higher seed yield and its components and seed protein. We conclude that N and P application as well as Nitroplus inoculation can help increase seed yield of soybean in Cambodia.

Agriculture in Africa is adversely affected by the loss of soil fertility. Conservation agriculture (CA) was introduced to curb the loss of soil fertility and water shortages and improve crop productivity. However, information on how CA practices enhance soil quality and nutrients is scarce in the sub-Saharan Africa context. The objective of this study was to investigate the effects of CA and conventional tillage (CT) on soil organic matter and nutrients under irrigated and rainfed vegetable on-farm production systems. During the dry and wet monsoon phases in the northern Ethiopian Highlands, a four-year experiment with CA and CT was carried out on ten vegetable farms under rainfed and irrigated conditions. Although the increase in concentration of organic matter in CA was generally slightly greater than in CT, the difference was not significant. The average organic matter content in the top 30 cm for both treatments increased significantly by 0.5% a−1 from 3% to almost 5%. The increase was not significant for the 30–60 cm depth. The total nitrogen and available phosphorus concentrations increased proportionally to the organic matter content. Consequently, the extended growing season, applying fertilizers and livestock manure, and not removing the crop residue increased the nutrient content in both CA and CT. The increase in CA was slightly greater because the soil was not tilled, and hay was applied as a surface cover. Although CA increased soil fertility, widespread adoption will depend on socioeconomic factors that determine hay availability as a soil cover relative to other competitive uses.

Several technologies have been provided to farmers to increase production under the rainfed systems of Ethiopia. However, much attention has been focused on drought emergency relief and associated interventions. Conservation agriculture (CA), among others, has been recently encouraged as part of the sustainable intensification technology in the Ethiopian smallholder farming systems. However, CA research in Ethiopia has traditionally stayed for a long time on a station-based research approach over a controlled environment followed by demonstration plots conducted, in most cases, for a short period. Considering large natural agro-hydro-ecological diversifications and the socio-economic conditions of smallholder farmers, it is possible to envisage that various versions of CA may be adopted based on different climate and topographic settings. Hence it entails various forms of adoption research depending on the biophysical and socio-economic conditions. Therefore, adopting CA technology is not as simple as adopting the technology or its components, as adoption is not only based on benefits but is also a process of inculcating CA into the human and social elements (culture, gender, social, and beliefs), and integrating CA within the farming systems (e.g., crop type, rotations, and agronomic management), and production systems (e.g., irrigated, rainfed, and livestock). In this regard, a review of CA technology usage provides an important perspective to explore the findings and the functionality of current CA research systems regarding the nature of its development, promotion, and dissemination in Ethiopia. This manuscript explores how CA is viewed by local farmers and associated researchers using the results from station to farmer-designed on-farm studies in the Ethiopian highlands, including irrigated and rain-fed production systems. This review paper will be crucially important for researchers and policymakers to develop conservation agriculture as one strategic issue for future sustainable irrigation and natural resource conservation.

Small-scale irrigation in Ethiopia is a key strategy to improve and sustain the food production system. Besides the use of surface water for irrigation, it is essential to unlock the groundwater potential. It is equally important to use soil management and water-saving systems to overcome the declining soil fertility and the temporal water scarcity in the region. In this study, the solar MajiPump was introduced to enable dry season crop production in Ethiopia using shallow groundwater sources. The capacity of the MajiPumps (MP400 and MP200) was tested for the discharge head and discharge using three types of solar panels (150 W and 200 W rigid, and 200 W flexible). Besides, drip irrigation and conservation agriculture (CA) farming systems were evaluated in terms of water productivity and crop yield in comparison to the farmers’ practice (overhead irrigation and tilled farming system). Results indicated that the maximum discharge head capacity of the MajiPumps was 18 m, 14 m, 10 m when using MP400 with 200 W rigid, MP400 with 200 W flexible, and MP200 with 150 W rigid solar panels, respectively. The corresponding MajiPump flow rates ranged from 7.8 L/min to 24.6 L/min, 3 L/min to 25 L/min, and 3.6 L/min to 22.2 L/min, respectively. Compared to farmer’s practice, water productivity was significantly improved under the CA farming and the drip irrigation systems for both irrigated vegetables (garlic, onion, cabbage, potato) and rainfed maize production. The water productivity of garlic, cabbage, potato, and maize was increased by 256%, 43%, 53%, and 9%, respectively, under CA as compared to conventional tillage (CT) even under overhead irrigation. Thus, farmers can obtain a significant water-saving benefit from CA regardless of water application systems. However, water and crop productivity could be further improved in the combined use of MajiPump with CA and drip irrigation (i.e., 38% and 33% water productivity and 43% and 36% crop productivity improvements were observed for potato and onion, respectively). Similarly, compared to CT, the use of CA significantly increased garlic, cabbage, potato, and maize yield by 170%, 42%, 43%, and 15%, respectively under the MajiPump water-lifting system. Overall, the solar-powered drip irrigation and CA farming system were found to be efficient to expand small-scale irrigation and improve productivity and livelihoods of smallholder farmers in Ethiopia.

No-till (NT) cropping systems have the potential to enhance soil aggregation, providing physical protection and soil C sequestration. The existence of discrepancies in the impact of tillage on soil aggregation and soil C sequestration warrants further studies, particularly for different crop rotations. We hypothesized the following: a) NT biannual crop rotations tend to be more effective in restoring large macroaggregation and the concentrations of soil organic C (SOC), total N and permanganate oxidizable C (POXC) associated with macroaggregates than NT systems with a one-year frequency pattern and conventional tillage (CT); b) the continuous biomass-C inputs via crop residues in large macroaggregates under NT tend to increase the proportion of aliphatic C than those under CT. Therefore, the objectives of this study were: (i) to assess changes in the aggregate size distribution and levels of aggregate-associated total SOC, total N and POXC and (ii) to characterize humic acid (HA) using C-13 CP-MAS nuclear magnetic resonance (NMR) spectra of 8- to 19-mm soil aggregate size class in a reference vegetation (RV) and in rice-, soybean- and cassava-based cropping systems (RcCS, SbCS and CsCS, respectively) in a clayed Oxisol after tillage and crop rotation management. We evaluated four treatments in each cropping system: 1) CT, and 2) three NT systems in a randomized complete block design with three replicates. Soil aggregate samples were collected at depths of 0-5, 5-10 and 10-20 cm. The conversion of RV to agricultural land influenced the distribution of aggregate size classes, soil aggregation indices and aggregate-associated SOC, total N and POXC in the two surface layers. The formation of large macroaggregates (8-19 mm) dominated the aggregate size distribution with a relatively higher proportion under RV and NT than under CT. Across all soil depths, the proportions of the 8- to 19-mm aggregate size fraction were 59% (NV), 43% and 47% (RcCS), 45% and 53% (SbCS) and 34% and 37% (CsCS) for the CT and NT systems, respectively. Among the three NT systems, the biannual crop rotations in the three cropping systems (NT2-Rice, NT2-Soybean, NT2-Cassava; NT3-Rice, NT3-Soybean and NT3-Cassava) indicated better performance than the one-year frequency pattern in restoring large macroaggregation and the concentrations of SOC, total N and POXC associated with large macroaggregates. Additionally, in the surface (0-5 cm) and subsurface (10-20 cm) soil layers, the SbCS with a high rate (7.32 Mg C ha(-1) year(-1)) and diversity [Pennisetum typhoides) (Pearl millet)/maize + Brachiaria ruziziensis (Brz), Stylosanthes guianensis (St)] of biomass-C inputs reached the highest levels of lability of SOC and POXC in the macroaggregate size classes of 0.25-0.5 and 8-19 mm, respectively. The CP-MAS C-13 NMR measurement suggests that the continuous and high biomass-C inputs with diverse crop residues under NT, such as millet, maize, Brz, St and Crotalaria juncea, tended to increase the proportion of aliphatic C than under CT; an opposite trend was observed for aromatic C. C-13 NMR revealed an advance caused by the association between the quantity and quality of C addition via cultural residues in the discrimination of the composition of C in the macroaggregation in the tropical region.

The main objective of this research was to evaluate land use and land cover (LULC) change in Battambang province of Cambodia over the last two decades. The LULC maps for 1998, 2003, 2008, 2013 and 2018 were produced from Landsat satellite imagery using the supervised classification technique with the maximum likelihood algorithm. Each map consisted of seven LULC classes: built-up area, water feature, grassland, shrubland, agricultural land, barren land and forest cover. The overall accuracies of the LULC maps were 93%, 82%, 94%, 93% and 83% for 1998, 2003, 2008, 2013 and 2018, respectively. The LULC change results showed a significant increase in agricultural land, and a large decrease in forest cover. Most of the changes in both LULC types occurred during 2003–2008. Overall, agricultural land, shrubland, water features, built-up areas and barren land increased by 287,600 hectares, 58,600 hectares, 8300 hectares, 4600 hectares and 1300 hectares, respectively, while forest cover and grassland decreased by 284,500 hectares and 76,000 hectares respectively. The rate of LULC changes in the upland areas were higher than those in the lowland areas of the province. The main drivers of LULC change identified over the period of study were policy, legal framework and projects to improve economy, population growth, infrastructure development, economic growth, rising land prices, and climate and environmental change. Landmine clearance projects and land concessions resulted in a transition from forest cover and shrubland to agricultural land. Population and economic growth not only resulted in an increase of built-up area, but also led to increasing demand for agricultural land and rising land prices, which triggered the changes of other LULC types. This research provides a long-term and detailed analysis of LULC change together with its drivers, which is useful for decision-makers to make and implement better policies for sustainable land management.

Highlights Soil type, operational speed, machinery weight, and power size affected corn seeding rate and seeding efficiency Corn growth and yield was affected by seeder type, so utilization of appropriate machinery is very important Having cover crop residue on the land can maintain soil moisture for a longer time than tilled land Abstract.Conservation agriculture (CA) is gaining popularity in Cambodia to sustain soil fertility, productivity, and profits. However, the adoption remains slow due to the low engagement so far of local services into CA machinery and technology. Therefore, this paper aimed to compare different no-till seeders and residue retention methods for corn (Zea mays L.) sowing and to determine their effects on growth and yield. The experiment was conducted in Rattanak Mondul District, Battambang Province, in the wet season of 2019. Sunn hemp (Crotalaria juncea L.) was grown as a cover crop for 74 days prior to corn. Each main plot was 14 × 34 m and was subdivided lengthwise with 4.0-m buffers for operations of two different seeders, namely one-row Morrison seeder mounted on 14 kW Oggun tractor and four-row Brazilian seeder mounted on 56 kW John Deere tractor. The results show that using Brazilian seeder saved around 50% of seed and 80% of time, when compared with Morrison seeder. Plant population, plant diameter, and kernel characteristics were also significantly greater with Brazilian seeder, when compared to the Morrison seeder. A combination of the Brazilian seeder and Cambodia made crimper plots had larger ear size and weight. Volumetric Moisture Content (VMC) was significantly affected by residue retention with higher VMC for rolled and crimped residue compared to disked/incorporated residue. The study demonstrates that using no-till equipment such as roller crimpers and no-till planters is feasible in Cambodia’s small farming systems although more research is needed to study long-term effects on crop yields and soil health. Keywords: Battambang Province, Conservation agriculture, Green manure, Soil improvements

A study was undertaken in Koun Mom district of Ratanakiri province in Cambodia to analyze the perceptions of the current status and constraints to soybean production and identify solutions to improve production and the management practices. Primary data were collected by personal interviews at field level of 130 producers. Most respondents were in the medium age category, Grade 4 education, with an average land holding of 2.96 ha and annual income of KHR 6,195,548 Riels (about 1548 USD). In terms of economic and production constraints, the high cost of fertilizers, severe insect and disease infestation, were identified as most important. Association with independent characteristics and scientific orientation were not significant, but education, land holding, annual income, socioeconomic status, and risk preference were significantly associated with constraints to soybean production. Within the context of sustainable agricultural production practices, it is suggested to improve high-yielding genotypes, ensure timely availability of high-quality seeds, and identify appropriate crop management practices (planting dates, planting density, nutrient and water management practices) and find ways to efficiently and effectively disseminate information to farmers to enhance soybean production in the region. In addition, extension agents and other agencies should provide soybean farmers marketing information, establish viable links between farmers and relevant stakeholders and private sector to improve access to inputs and modern technologies while the local and state governments should establish rural markets with good market infrastructure to enable farmers have high returns from soybean production.

This study was conducted at the Dangishta watershed in the Ethiopian highlands to evaluate irrigation potential from surface and groundwater sources under different farming and water application systems. Daily streamflow and the groundwater table were monitored from 2015 to 2017. Shallow groundwater recharge was estimated using the water table fluctuation method. Automated baseflow separation techniques were used to determine the amount of runoff and baseflow from the total streamflow records. The potential of groundwater and runoff to sustain dry season irrigation (i.e., low flow) was evaluated considering two tillage systems (i.e., conservation agriculture, CA; and conventional tillage, CT), and water application (i.e., drip and overhead) systems for major irrigated crops (i.e., onion, garlic, cabbage, and pepper) grown in the Dangishta watershed. We found that the annual groundwater recharge varied from 320 to 358 mm during the study period, which was about 17% to 22% of the annual rainfall. The annual surface runoff depth ranged from 192 to 268 mm from 2015 to 2017. The results reveal that the maximum seasonal irrigable land from groundwater recharge was observed under CA with drip irrigation (i.e., 2251 and 2992 ha from groundwater recharge and surface runoff, respectively). By comparison, in the CT practice with overhead irrigation, the lowest seasonal irrigable land was observed (i.e., 1746 and 2121 ha from groundwater and surface runoff, respectively). From the low flow analysis, about 199 and 173 ha of one season’s irrigable land could be irrigated using the CA and CT systems, respectively, both with drip irrigation. Similarly, two-season overhead irrigation potential from low flow under CA and CT was found to be about 87 and 76 ha, respectively. The dry season irrigable land using low flow could be increased from 9% to 16% using the CA system for the various vegetables, whereas drip irrigation could increase the irrigable land potential by 56% compared to overhead irrigation. The combined use of groundwater recharge and runoff could sustain up to 94% of the dry season low flow irrigation through the combination of the CA system and drip irrigation. Decision makers must consider the introduction of feasible and affordable technologies to make use of groundwater and direct runoff, to maximize the potential of dry season production through efficient and appropriate CA and water management practices.

: Vegetables are vital for human health and are consumed five days a week in Cambodia. However, the production cannot meet domestic demands due to labor-intensive farming and production costs related to soil tillage. Mechanization is needed along with soil quality and sustainability improvements by the adoption of CA (Conservation Agriculture). The research aimed to compare the performance of the no-till vegetable transplanter with punch-planter in CA and hand transplanting in CT (Conventional Tillage). The study was conducted at the Royal University of Agriculture, Cambodia, starting from January to September 2020, by firstly growing sunn hemp as a cover crop and then transplanting Thai round eggplant. A randomized complete block design was used with three treatments, replicated three times. Each plot was 2 m by 15 m, with 0.2-m row spacing. The results showed that the transplanter speed was 0.54 km (cid:120) h -1 , almost two times the speed of punch planter and 9 times the speed of hand transplanting. The highest working capacity was also achieved with the transplanter. However, different transplanting did not affect plant spacing, or plant density. Plant spacing was 1 m, and plant density varied from 10,300 to 11,500 plants (cid:120) ha -1 . Plant growth and yield were also not influenced by the transplanter in CA, or hand transplanting in CT. Average fruit diameter, fruit weight, fruit number, and yield were 38 mm, 31.4 g (cid:120) fruit -1 , 15.7 fruits (cid:120) plant -1 and 3.9 t (cid:120) ha -1 , respectively. The maximum working area of the transplanter and its break-even area were 25.2 ha (cid:120) y -1 and 18.3 ha (cid:120) y -1 , respectively. Using the no-till transplanter may save both time and labor, but its use in combination with CA was unlikely to affect plant growth and yield in the short term.

General knowledge based on the good agricultural soils in temperate climates is that no-till and conservation-till practices increase infiltration of the rainwater and decrease runoff and erosion. Experiments in the semi-humid Ethiopian highlands do not often show the same benefits and in many cases no-till actually increases runoff above conventional and deep tillage. In contrast, for conservation-tillage with mulch at the surface, more of the water infiltrates and enhances plant growthReduced tillage systems increase infiltration through soil fauna that form soil macropores through which rainwater flows to the subsoil bypassing the soil matrix with limited conductivity. Most degraded soils (at least in the Ethiopian highlands) have a hardpan at shallow depths restricting downward movement of water. Runoff on conventionally tilled soils is caused by saturation excess when the perched water table in the plowed soil layer reaches the surface. Thus, the amount of runoff is determined by the water free pore space in the surface layer. Since this pore space is less under no-till, no-till has greater amounts of runoff than conventional till.Under mulch tillage, organic matter is introduced at the surface and soil fauna becomes well-developed which will improve the soil structure and porosity of the soil. This structure will be maintained because the mulch decreases the sediment concentration in the water and the pores will remain open. Under conventional tillage sediment concentrations are high and any pores formed will be filled up with sediment. Our expectation is that since organic matter under mixed farming is used to feed the cattle, widespread implementation of no-till and conservation tillage will be limited to areas with high value crops in which farmers can afford using organic matter as a mulch.

Improving smallholder vegetable farms are critical for improving food security and livelihoods of people in low-income countries. Vegetable production is labor intensive and prone to pests and diseases. Conservation agriculture (CA) and integrated pest management (IPM) practices provide options to increase yields and minimize the use of chemical pesticides. We compared integration of CA and IPM practices (improved alternative system) with farmers’ traditional practice (conventional system) under replicated on-farm tests in four different locations (Lalitpur, Banke, Surkhet, and Dadeldhura) in Nepal. Data on yield, benefit–cost ratio (B:C), labor requirement, insect and disease infestation, and pesticide sprays on five major vegetable crops (tomato, cucumber, bitter gourd, cabbage, cauliflower) were measured. In tomatoes, cucumbers, and bitter gourds, the improved alternative system produced a significantly higher yield, greater benefit-cost ratio, reduced labor, decreased the infestation of pests and diseases, and required fewer pesticidal sprays. Average yield and net income were superior in cabbages and cauliflowers, but nonsignificant. Improved alternative system for all the vegetables were sprayed significantly fewer times than the conventional system. Overall, the improved alternative system for vegetable crops contributed not only to the improved income and livelihoods of people, but also can improve environment and human health due to the reduced use of pesticides. Further research on scaling these improved alternative practices through appropriate farmer organizations, and government and non-government actors can enhance the adoption of CA and IPM practices by smallholder vegetable producers.

The number of local small farms in the USA is on the rise due to a consumer demand for locally grown produce such as tomatoes. These farms often use small walk-behind tractors, but most field activities are still performed by hand requiring heavy physical labor. Recent efforts from USDA have been encouraging producers to adopt no-till techniques using cover crops for benefits such as reduced runoff and soil erosion, increased infiltration and water holding capacity, increased soil organic carbon, decreased soil compaction and improved weed control. However, lack of specialized no-till equipment inhibits widespread adoption of cover crops. To help small farms reduce hand labor and adoption of conservation systems with cover crops, no-till equipment such as a no-till drill, powered roller/crimper, and no-till transplanter have been developed for walk-behind tractors at the National Soil Dynamics Laboratory in Auburn (AL, USA). A replicated three-year field test (2017–2019) was conducted to evaluate effectiveness of the experimental powered coulter drill to plant cereal rye cover crop (Secale cereale, L.), patented powered roller/crimper to terminate rye, and transplanting cash crop tomato (Solanum lycopersicum L.) seedlings with a patented no-till transplanter. These three pieces of equipment were compatible with BCS 853 walk-behind tractor. The experiment was conducted on two different soils: Hiwassee sandy loam soil and Davidson clay to determine the performance of developed machines under different soil types. Results have shown that the powered coulter drill generated effective rye seed emergence (83%) for optimum biomass production. The experimental powered roller/crimper generated 95% rye termination rate three weeks after rolling, and the no-till transplanter performed as anticipated providing less than 10% variation of plant spacing uniformity. Tomato yield varied among years ranging from 15.9 Mg ha−1 to 28.3 Mg ha−1 and was related to different soil and weather conditions at each growing season. Numerically higher tomato yield on Davidson clay might be associated with less insect/pathogen pressure, higher plant available water, and reduced weed pressure due to greater cereal rye biomass production. Results from this experiment indicate that developed experimental equipment can be a practical solution for small no-till farming operations with cover crops.

Smallholder agriculture constitutes the main source of livelihood for the Ethiopian rural community. However, soil degradation and uneven distribution of rainfall have threatened agriculture at present. This study is aimed at investigating the impacts of conservation agriculture on irrigation water use, nutrient availability in the root zone, and crop yield under supplementary irrigation. In this study, conservation agriculture (CA), which includes minimum soil disturbance, grass mulch cover, and crop rotation, was practiced and compared with conventional tillage (CT). We used two years’ (2018 and 2019) experimental data under paired-t design in the production of a local variety green pepper (Capsicum annuum L.). The results showed that CA practices significantly (α = 0.05) reduced irrigation water use (13% to 29%) and runoff (29% to 51%) while it increased percolated water in the root zone (27% to 50%) when compared with CT practices under the supplementary irrigation phase. In addition, CA significantly decreased NO3-N in the leachate (14% to 44%) and in the runoff (about 100%), while PO4-P significantly decreased in the leachate (33% to 50%) and in the runoff (16%) when compared with CT. Similarly, CA decreased the NO3-N load in the leachate and in the runoff, while the PO4-P load increased in the leachate but decreased in the runoff. The yield return that was achieved under CA treatment was 30% higher in 2018 and 10% higher in 2019 when compared with the CT. This research improves our understanding of water and nutrient dynamics in green pepper grown under CA and CT. Use of CA provides opportunities to optimize water use by decreasing irrigation water requirements and optimize nutrient use by decreasing nutrient losses through the runoff and leaching.

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.