Agrosystems, Geosciences & Environment最新文献

Despite the promising potential of soybean [Glycine max L. (Merrill)] production in Ethiopia, smallholder farmers face challenges such as low yields and nutrient deficiencies, which limit their productivity and economic stability. Thus, the objectives of the input diagnosis/demonstration trials were to enhance the yields of smallholder soybean farmers, to explore the interaction and variations of soybean yield responses to phosphorus (P) and/or inoculant (I) applications across multiple locations, and to identify the economic benefits from phosphorus (P) and/or inoculant (I) use on the fields of many smallholder farmers, representing diverse agroecological conditions. The application of P, I, P + I, and control was evaluated on 78 farmers’ fields in 10 districts. The result indicated that the combined use of I + P and P alone enhanced grain yield by 42% and 21%, respectively. The use of the inoculant only also increased the yield by 5% over P alone. Although P + I showed the highest yield and 80% of the farmers observed positive yield, the variability was very large (0.3–5.3 t ha⁻¹). Moreover, the inoculant was more profitable compared to P. Notably, 15% of the total farmers experienced relative yield increases of 142%–368% under the combined use of P and I. In addition, about 52%, 50%, and 15% of farmers achieved at least 5000 ETB ha⁻¹ (where ETB is Ethiopian Birr) of an economic benefit with the application of corresponding P + I, I, and P. Considering price fluctuation of variable cost by assuming 30% inflation after some years, use of the of inoculant alone and then integrated use of P and I were relatively more stable as 46% and 60% of the total farmers could respectively attain benefit to cost ratio ≥2. While most smallholder farmers benefited from the use of P + I or I only, a few of them still did not benefit from the technologies. This may need further investigation, particularly for nonresponsiveness soils. Therefore, understanding the causes of yield variability helps to cluster the best bet packages to groups of farmers who are expected to benefit most, reduce yield gain instability across the farm plots, and minimize higher risk for technology adoptions.

The Universal Soil Loss Equation incorporates soil erodibility as a key parameter for erosion quantification. This study focused on mapping soil erodibility patterns and identifying the primary factors influencing its spatial distribution within the Ravang watershed, located in southern Iran's Hormozgan Province. To ensure representative and stratified spatial coverage, 100 sites within the study area were selected for soil samples using the conditioned Latin hypercube sampling method. Spatial modeling of soil erodibility was performed by assessing variables such as organic carbon content, soil texture, structure, permeability, and erodibility, and applying random forest and boosted regression trees algorithms. The mean soil erodibility in the study area was 0.27 t·ha·h/(ha·MJ·mm). The results indicated comparable accuracy between both methods. Variable importance analysis revealed that maps of very fine sand, medium sand, and total sand content were the most significant predictors of soil erodibility distribution. Furthermore, incorporating soil texture fraction maps enhances prediction accuracy in soil erodibility modeling. The highest soil erodibility rates were identified in the southern and southwestern portions of the Ravang watershed through spatial mapping. Soil erosion mapping provides critical data to prioritize areas for erosion control interventions, helping to mitigate land degradation in vulnerable regions similar to the southern Iranian study area. To achieve enhanced spatial accuracy in digital soil erodibility mapping, we recommend incorporating soil texture fraction maps as essential input variables in comparable studies, given their demonstrated importance in optimizing predictive model performance.

Soils serve as a major reservoir for atmospheric carbon and could play a key role in mitigating climate change. Since deep soil layers can store substantial amounts of organic carbon, they should be included in carbon and nitrogen estimates. This study examined soil organic carbon and nitrogen at different depths under enset-based farming systems in Ethiopia and determined the association with household wealth. We compared organic carbon and total nitrogen in two locations in Ethiopia, Haise and Yeferezye, on enset farms that have been established for over 30 years. The results showed that organic carbon varied significantly with management practices of different wealth categories. At Haise, organic carbon in 0–15 cm layer was 4.9% under resource-rich farmers, significantly higher than 3.5% under resource-poor farmers. At Yeferezye, organic carbon under resource-rich management (4.4%) was higher than in soils managed by both medium-wealth and resource-poor farmers. In the upper layers (0–30 cm) of enset fields, organic carbon stocks were 15.3% higher at Haise and 4.6% higher at Yeferezye under resource-rich management, reflecting differences in the quantity of organic inputs applied. Our work suggests that enset systems store substantial amounts of organic carbon and nitrogen below the main rooting depth (40 cm), with household wealth influencing these concentrations through differences in manure availability. However, this conclusion is based solely on internal comparisons within enset systems, without reference to other land uses. To quantify threats and opportunities associated with enset farming, further studies are needed to understand how land use change away from enset would impact stored carbon and nitrogen.

The use of preemergence (PRE) herbicides with soil residual activity is recognized as an effective strategy for early-season weed management in Midwest US soybean [Glycine max (L.) Merr.] production. The efficacy of soybean PRE herbicides with single and multiple sites of action (SOAs), including acetolactate synthase (ALS), photosystem II, protoporphyrinogen oxidase (PPO), and very long-chain fatty acid (VLCFA) inhibitors, was assessed in a randomized complete block design across 4 site-years (Brooklyn-2019, Fond du Lac-2019, Lancaster-2018, and Lancaster-2019) for waterhemp [Amaranthus tuberculatus (Moq.) J.D. Sauer] and three site-years (Janesville-2019, Janesville-2020, and Janesville-2021) for giant ragweed (Ambrosia trifida L.) in Wisconsin. The data were pooled across site-years, and the results are presented by species to highlight the most effective herbicide treatments across varying environmental conditions. Several single- and multiple-SOA PRE herbicides from the photosystem II (PS II), PPO, and VLCFA groups effectively (>90%) controlled waterhemp at 21 and 42 days after treatment (DAT) and significantly reduced biomass (>86%) 42 DAT. Similarly, single ALS PRE herbicides group, as well as premixes containing ALS + PPO, ALS + PS II + PPO, and ALS + PPO + VLCFA, provided 79%–92% giant ragweed control at 21 and 42 DAT and reductions in biomass by 80%–95%. Our data show a positive correlation between biomass reduction and visual weed control assessments for both waterhemp and giant ragweed, suggesting that quality visual assessments can serve as a reliable proxy for evaluating PRE herbicide efficacy. Our results suggested that PRE herbicide containing two or three SOAs provided greater and more consistent control and biomass reduction of waterhemp and giant ragweed compared to single-SOA PRE herbicides.

Ethiopia is Africa's second-largest sorghum producer [Sorghum bicolor (L.) moench]. Despite these potentials, the production and productivity of sorghum yield remained low due to many agricultural factors. Among the factors, sorghum anthracnose caused by Colletotrichum sublineolum is one of the main fungal diseases substantially reducing sorghum grain yield. Hence, this study was undertaken to assess the intensity of anthracnose on sorghum fields, and its association with biophysical factors. Sorghum is the fifth most important cereal crop globally and a crucial food source for millions in sub-Saharan Africa. In total, 350 sorghum fields (187 in 2020 and 163 in 2021) were surveyed during the main cropping seasons from October to November at the early to hard dough stages across the three regional states. Infected sorghum leaves were sampled and associated factors were identified. The results of this study revealed that the overall prevalence of sorghum anthracnose in sorghum fields across Western and Southwestern Ethiopia was 100%. Sorghum fields were shown varied levels of sorghum anthracnose incidences that ranged from 46.15% to 100% in Assosa, 55.5% to 100% in Jimma, 75% to 84.62% in Illubabor, 78.5% to 100% in East Wollega, and 85.7% to 100% in Gambella with the mean incidence of 83.78%, 85.81%, 78.10%, 78.57%, and 91.79.70%. Besides, the severity of anthracnose was high in Jimma, Assosa, Agnuwak, Illubabor, and East Wollega with mean field severity of 35.25%, 34.5%, 28.97%, 28.32%, and 27.60%, respectively. The study found that biophysical factors, such as proper weed management, crop rotation, recommended fertilizer application, sowing date, use of disease-free seeds, and weather conditions were directly associated with sorghum anthracnose development.

Despite direct seeding, seed pelletizing with useful materials is one of the effective methods to improve plant growth. This experiment assessed the impacts of different additives used in seed pelletizing on germination and growth of Onobrychis viciifolia at a degraded semi-arid rangeland. Seed pellets were prepared for the 16 treatments, which included 14 amendments (seven additives at two 10% and 20% concentration levels) and two controls (a clay-only pellet and direct seeding). After the planting, germination indices and growth traits were recorded and analyzed. A completely randomized design was considered in planting experiment using 12 seedballs as replications per treatment. The results revealed that corn starch 20% treatment had the lowest value for growth and germination, while the livestock manure 20%, sawdust 20%, ash 10%, and wheat straw 10% showed better germination indices. Based on the significance summation ranking method, sawdust was the most favorable amendment, enhancing root length by 23%, root weight by 234%, aerial biomass weight by 189%, and plant height by 31% compared to the direct seeding. The efficacy of seed pelleting over direct seeding was clearly demonstrated. Notably, seedballs prepared solely from clay, without any amendments, also showed acceptable performance in enhancing seed germination and plant growth. However, some of the used additives, such as ash, sawdust, and manure, were more beneficial than using clay alone in the seedball production. Seed pelletizing did not always have favorable results with all materials. For instance, additives such as starch, especially in high concentrations, had adverse effects.

Potassium (K) is an essential macronutrient vital for plant growth and crop production. However, the misconception that K fertilization is unnecessary has long persisted in Ethiopia. Hence, a field experiment was conducted during the 2021 and 2022 cropping seasons on Nitisol and Cambisol soils to evaluate the response of teff [Eragrostis tef (Zuccagni) Trotter] to different K fertilizer rates in terms of yield, nutrient concentration, uptake, and use efficiency. The K rates (0, 60, 120, and 180 kg K ha⁻¹) were applied as muriate of potash (KCl) in a randomized complete block design with three replications. Results showed that K application significantly (p < 0.01) increased teff grain yield on both soils. The application of 120 kg K ha⁻¹ produced yield gains of 39.4% and 36.7% over the control on Nitisol and Cambisol, respectively. The highest mean straw nitrogen (N) concentration (6.63 g kg⁻¹) on Nitisol was recorded in the control plot, while the lowest was recorded with an application of 180 kg K ha⁻¹. On Cambisol, plant N, phosphorus (P), and K uptakes were significantly (p < 0.05) higher, with maximum values of 74.7, 31.9, and 95.4 kg ha⁻¹, respectively, under 120 kg K ha⁻¹. On Nitisol, only N uptake was significantly affected, reaching 61.3 kg ha⁻¹. Potassium (K) application also improved agronomic K use efficiency on both soils. These findings refute the long-held belief that Ethiopian soils are inherently rich in K. Future fertilizer recommendations for teff production on Nitisols and Cambisols should include K fertilization to improve productivity.

Rice weevils (Sitophilus oryzae), a major storage pest, cause both qualitative and quantitative losses of stored grains. Normally, chemical insecticide along with fumigation is practiced for the management, but it creates health hazards. So, this study investigates the effects of temperature and duration of exposure on rice weevils. Completely randomized design with two factors—factor (A) eight treatments: T₁ = −80°C, T₂ = −20°C, T₃ = 4°C, T₄ = 20°C, T₅ = 25°C, T₆ = 35°C, T₇ = 40°C, and T₈ = 50°C; factor (B) three durations of exposure—was carried out with three replications at laboratory condition of Entomology Division at Bangladesh Rice Research Institute from October 2023 to November 2024. The mortality percentage varied significantly across temperature and hours exposure time (HET), with 100% mortality observed at extreme temperatures (−80°C, −20°C, and 50°C) at 24, 48, and 72 HET. At moderate temperatures (20°C, 25°C, and 35°C), mortality was negligible to moderate (0%–11.67% at 24 HET and 48 HET), but increasing with prolonged exposure time (48.33% at 72 HET). Although 100% weevil mortality was achieved at 40°C, it required slightly extended durations (48 and 72 HET) for the 100% mortality. The F₁ adult emergence was highest (124.67) at 25°C, indicating optimal thermal conditions for rice weevil reproduction and development, while extreme temperatures completely inhibited adult emergence. The developmental period was shortest at 25°C and prolonged at 4°C, reflecting the metabolic slowdown at lower temperatures. There were no F₁ adults emerged at extreme temperatures (−80°C, −20°C, and 50°C), highlighting lethality of these thermal conditions. Weight loss of grains was highest at 20°C, 25°C, and 35°C due to active feeding and breeding, and highest number of F₁ adults emerged, while the minimal occurred at extreme temperatures. Low (<4°C) and high (>35°C) temperatures were particularly effective with prolonged exposure time for developing temperature-based management practice. Weevil biology is influence by temperature, with low prolonging development but increasing mortality, moderate optimizing survival, increasing weight loss, and high reducing survival through biological stress.

Brachiaria production is an important segment in Brazil's agriculture, used as a forage or animal feed. Studying the influence of Brachiaria sp. on soil nitrogen (N) dynamics under different soil pH and amendment conditions is a critical research need. An experiment was conducted in a greenhouse in the Department of Plant Production at Sao Paulo State University (UNESP), Brazil. Four Brachiaria species were evaluated (Brachiaria brizantha, Brachiaria decumbens, Brachiaria humidicola, and Brachiaria ruziziensis), they were grown in soils with a pH varying between 4 and 6. Calcium hydroxide [Ca (OH)₂] and magnesium oxide (MgO) were used at different rates to correct soil pH and test soil amendment effects in Brachiaria production. The Soil Plant Analysis Development chlorophyll index was determined biweekly throughout the experimental period. Other assessments were carried out 60 days after planting. The dry biomass of the aerial part (leaves + stem) of Brachiaria plants were quantified, as well as the N concentrations and total content. The root development was also studied (length, average diameter, and surface area). The soil was divided into rhizospheric soil and non-rhizospheric soil, the levels of total N, ammonium (N-NH₄⁺), nitrate (N-NO₃⁻), pH, and organic matter were determined. Our findings showed that the behavior of all four Brachiaria species responded positively to soil amendment in terms of dry matter production and in general, no definite effect of Brachiaria and/or pH on the nitrification process was detected. However, N use efficiency was higher under lower soil pH levels. When grown at the lowest soil pH (4), B. humidicola and B. ruziziensis showed the highest dry matter production. This effect, connected with the fact that all species produced the same amount of dry matter when grown at the highest pH, places B. humidicola and B. ruziziensis as the most tolerant to soil acidity, which may become better Brachiaria options for farmers in regions with more acidic soils in Brazil.

Enhancing feed resource availability and nutritional qualities with healthful soil management practices is a decisive intervention for future livestock husbandry in developing countries. However, there is a need for sound recommendations on agronomic practices and fertilization due to local differences in the climate and soil profiles. Therefore, this study evaluated the intercropping effects of desho grass (Pennisetum glaucifolium) with vetch (Vicia villosa) variety of Var-Lalisa on soil fertility, forage accumulation (FA), and nutritional compositions among seeding rates across harvest days. The experiment was conducted in a randomized complete block design for intercropping of the desho grass with vetch at the seeding rates of 12 kg/ha (T1), 9 kg/ha (T2), 6 kg/ha (T3), 0 kg/ha or sole desho grass (T4), and sole vetch (30 kg/ha) (T5) with three replications. Data on soil profile in depths, plant height, biological compatibility and yield advantage, FA by forage type, and chemical compositions were studied across harvesting. The intercropping effect was substantially greater (p < 0.05) on plant height and FA than sole sown desho grass at all harvests. Moreover, T1 had the highest total forage accumulation (TFA), crude protein (CP), and in vitro organic matter digestibility (IVOMD). However, lower CP and IVOMD were obtained in T4 across the harvests. The sole desho grass yields significantly (p < 0.05) higher ash, acid detergent fiber, neutral detergent fiber, and acid detergent lignin contents. Therefore, the intercropping effect of T1 at higher sowing rates of vetch can maximize the TFA and soil nutrient utilization efficiency, and this can be suggested for further accession study in a range of agroecologies for adoption.