Agrosystems, Geosciences & Environment最新文献

Soil is a fundamental resource for plant growth and ecosystem sustainability, yet limited site-specific soil information has hindered optimal sugarcane (Saccharum officinarum L.) production in the Arjo-Dhidhesa Estate Sugar Factory Development Project area, Oromia, Ethiopia. This study aimed to characterize and classify the soils across 28,092 ha to inform sustainable land management and enhance sugarcane productivity. A detailed field survey was conducted, including 90 auger observations and the selection of representative pedons, following Food and Agriculture Organization soil description guidelines. Physical and chemical properties such as texture, bulk density, pH, organic carbon, and exchangeable bases were analyzed. The results revealed considerable variability in soil properties among pedons. Most exhibited clay to heavy clay textures favorable for water and nutrient retention, while Pedon A-5 showed sandy clay loam, suggesting better drainage. Variations in bulk density, porosity, and water-holding capacity reflected differences in root penetration and moisture availability. Soil pH ranged from slightly acidic to neutral, and several pedons demonstrated high organic carbon, cation exchange capacity, and exchangeable calcium indicative of good fertility. These findings underscore the importance of site-specific soil data in guiding sugarcane management. The diversity of soil types across the estate necessitates tailored strategies to enhance productivity and support sustainable agriculture. This study provides a foundation for implementing targeted soil management practices to improve crop yields and long-term soil health in the Arjo-Dhidhesa Estate Sugar Factory.

Summer fallow practices are of increased interest in semi-arid irrigated areas of the western United States as a means to replenish water resources. Understanding of cereal residue decomposition in these conditions is limited, and data are needed to develop guidance. Research was conducted from 2018 to 2020 in Aberdeen, ID. Residue decomposition bag studies assessed crop type (barley [Hordeum vulgare L.], corn [Zea mays L.], hard red wheat [Triticum aestivum L.; HRW], and soft white wheat [SWW]), tillage (surface and incorporated), and supplemental fertilizer-N rates (0, 56, and 112 kg N ha⁻¹) collected after application (spring, summer, and fall). Barley, corn, HRW, and SWW carbon:nitrogen (C:N) ratios were 74, 62, 105, and 87, respectively. Crop type and tillage affected residue decomposition, but fertilizer-N had no impact. Decomposition was greatest from post-harvest to spring for incorporated corn (37%) and least for surface barley, HRW, and SWW (21%). At the fall sampling, patterns were largely the same with minor changes from spring. Fertilizer-N decreased C:N ratio at the spring sampling but not at the summer or fall timings. First-order decay constants ranged from 0.00075 to 0.00300 day⁻¹ for surface HRW and incorporated corn, respectively. This equates to a timeframe of 231–929 days for 50% of residue to decompose. Additions of fertilizer-N to increase residue decomposition were not supported by the data but incorporation of residue by tillage and lower C:N crop types did result in more rapid decomposition. Relatively slow rates of decomposition occurred, particularly when surface applied, and these estimates can be used to improve residue management in semi-arid regions.

Organic amendments enhance soil quality in agroecosystems, although they may modify the dynamics of greenhouse gas (GHG) emissions, highlighting complex interactions between soil management and environmental sustainability. A field experiment was conducted in the semiarid region of Iran to evaluate the effects of barley residues (BR), sheep manure (SM), and their combination (BR+SM) on soil carbon dioxide (CO₂) and nitrous oxide (N₂O) emissions under maize and mungbean. In mungbean, both SM and BR+SM resulted in higher CO₂ fluxes than BR. Conversely, in maize, cumulative CO₂ emissions were similar among treatments. Under mungbean, BR+SM exhibited higher soil N₂O values than SM and BR. The lowest cumulative CO₂ (4.77 ± 0.24 and 5.29 ± 0.37 Mg ha⁻¹ year⁻¹ for maize and mungbean, respectively) and N₂O (4.73 and 3.00 kg ha⁻¹ year⁻¹ for maize and mungbean, respectively) values were measured in the BR, whereas the BR+SM resulted in significantly high cumulative CO₂ and N₂O under both crops. Cumulative CO₂ fluxes were 21.5% and 53.5% lower in the BR than BR+SM under maize and mungbean, respectively. Similarly cumulative N₂O was 48% lower in the BR than in the BR+SM treatment under the mungbean cropping system. Application of BR can be considered as an effective alternative management strategy in terms of lowering GHG emissions under maize and mungbean. By exploring the impact of organic input management on soil carbon and nitrogen dynamics in semiarid cropping systems, our study provides key insights for enhancing agricultural sustainability, while reducing GHG emissions.

Hydrologic modeling studies within the United States frequently utilize the USDA-Natural Resources Conservation Service State Soil Geographic (STATSGO, 1:250,000 resolution) or Soil Survey Geographic (SSURGO, 1:24,000 resolution) database to characterize soil properties. The finer resolution of SSURGO enables more precise spatial modeling that is beneficial in locating hydrologically vulnerable regions. However, the coarser-resolution STATSGO results in quicker simulation runtimes, which can be computationally necessary in larger watersheds and for multi-decadal estimation periods. Extending runtime by several minutes for a single simulation translates into multiple days during calibration and optimization modeling, for which hundreds to thousands of runs may be needed. We developed a method to aggregate SSURGO using soil taxonomy while maintaining distinctions critical to hydrologic processes. We automated this process in R for the Soil and Water Assessment Tool (SWAT; https://www.climatehubs.usda.gov/hubs/international/tools/soil-and-water-assessment-tool) soil input data. Our method identifies hydrologically sensitive SSURGO map units, aggregates them up to the taxonomic subgroup level, and then creates the SWAT-required inputs from the subgroup characteristics. Soil horizons are then standardized by depth-weighting the SSURGO horizons. The taxonomic SWAT model ran twice as fast as the SSURGO model, predicted similar nutrient and sediment losses, and matched SSURGO identification of hydrologically vulnerable areas. The STATSGO model ran most quickly but also held the most water in the soil profile, likely due to much larger map units (309 ha each vs. 26 ha for SSURGO and 52 ha for taxonomic). Conversion of SSURGO into a taxonomy-based input layer supports more exploratory research by reducing processing time while maintaining similar precision levels.

This case study seeks to assess the long-term impact of manure usage on soil health and water under on-farm conditions. Explicitly, we concurrently monitored nutrient concentrations in shallow groundwater (nitrogen and phosphorus) and related in-field soil health indicators (permanganate oxidizable carbon, mineralizable C, and autoclaved citrate extractable-protein) on two fields located in northcentral Ohio with a historic legacy of annual cropping with and without manure utilization. Results indicated the usage of manure as a main source of nutrient can lead to lower nutrient concentrations for nitrogen in local shallow groundwater but showed virtually no direct influence on measurable soil health. These initial on-farm condition results are encouraging from the water quality perspective as they suggest that management alternatives such as wider utilization of manure associated with reintegration of crops and livestock could help reduce environmental impacts.

Degraded cool-season grass pastures pose a major challenge for sustainable forage production in the southeastern United States. Orchardgrass (OG; Dactylis glomerata L.), a widely used forage species, often exhibits poor persistence under suboptimal management and environmental stress, requiring restoration. Strategies that minimize soil disturbance while improving productivity and soil quality are needed to support long-term pasture sustainability. This study evaluated six low-disturbance strategies to restore OG pastures while preserving soil quality: (1) control (C-OG), (2) synthetic N fertilization (OG+N; 67 kg N ha⁻¹), (3) fall-seeded alfalfa (Medicago sativa L.) (FA), (4) spring-seeded alfalfa (SA), (5) FA combined with crabgrass (Digitaria sanguinalis L.; CG) (FA+CG), and (6) SA+CG. Treatments were applied from 2021 to 2022 in Spring Hill, TN, and evaluated for forage mass (FM), root biomass, and soil carbon (C) and nitrogen (N) concentrations. The OG-N treatment produced the greatest FM (2390 kg DM ha⁻¹, where DM is dry matter), while C-OG yielded the least (1927 kg DM ha⁻¹). Alfalfa and alfalfa+CG treatments produced intermediate yields, averaging 2159 kg DM ha⁻¹, and did not differ among them. Root biomass declined over time across all treatments but was unaffected by restoration strategy. Soil C and N concentrations remained stable throughout the 2-year period. These findings indicate that both N fertilization and legume-grass mixtures can enhance productivity without soil disturbance or nutrient loss. Integrating alfalfa and CG into existing OG pastures offers a sustainable restoration approach that supports forage production while maintaining soil health.

Gap-filling is used to mitigate yield losses in different legumes. There is scanty information on this mechanism of yield compensation in the cowpea [Vigna unguiculata (L.) Walp]. This study investigated responses of yield and yield components to plant density in some accessions of cowpea at Minjibir and Shika locations. The randomized complete block design, in a split-plot arrangement in three replicates, was used. The main plots consisted of four plant densities, while the sub-plots consisted of six cowpea accessions. Results showed that plant density and environment affected yield and yield components. Total grain yield increased as plant density increased at both locations and was highest in the accession DANILA (1793.3 kg ha⁻¹) at 99,999 plant ha⁻¹ and lowest in the accession IT98K-205-8 (1100 kg ha⁻¹) at 33,333 plants ha⁻¹. Pod yield was positively correlated with total grain yield at Minjibir (0.267*) and Shika (0.917**) and when data were combined (0.990**). Shelling percentage was negatively correlated with total grain yield when data were combined (−0.610**). Significant positive correlation between total grain yield and 100-seed weight as well as biological yield was observed at Shika. Harvest index was positively correlated with total grain yield (0.407**) at Minjibir. The study concludes that erect accessions (IT93K-452-1 and IT98K-205-8) and semi-erect accessions (IT99K-573-1-1 and IT08K-150-27) could be adopted for cultivation at 133,333 plants ha⁻¹, while prostrate accessions (IT89KD-288 and DANILA) could be cultivated at 99,999 plants ha⁻¹ at Minjibir. The accessions IT93K-452-1, IT98K-205-8, IT99K-573-1-1, and IT08K-150-27 could be cultivated at Shika, irrespective of plant density.

The use of conventional tillage practices in crop production systems has led to a significant soil loss in many regions of Iran. Conservation tillage practices can help restore the degraded soils. A 2-year experiment was conducted in an irrigated corn (Zea mays L.) cropping system during the 2014–2016 growing seasons on a silty clay soil with a Mediterranean climatic condition. The experiment was carried out as a split plot based on a randomized complete block design with three replications. The main factor was the tillage system in three levels (conventional tillage, reduced tillage, and no tillage), and the sub-factor was the corn hybrid including KSC704, AS71, BC678, and Simon. Results showed that the surface layer of the soil (0- to 20-cm depth) was more affected by tillage systems, so that conservation tillage systems (reduced and no tillage) improved physical (including soil moisture contents at field capacity and permanent wilting points, the amount of water-dispersible clay, and mean weight diameter of the soil aggregates), chemical (including the amount of soil organic carbon, cation exchange capacity, total nitrogen, phosphorus, potassium, and iron), and biological (including microbial biomass carbon, basal and substrate-induced respiration, metabolic quotient, and the activity of soil extracellular enzymes) properties of the soil. For example, soil organic carbon under no and reduced tillage systems was higher by 28% and 22%, respectively, compared to conventional tillage. In general, the results revealed that tillage practices even in a relatively short-term period can notably affect soil characteristics.

Common bean (Phaseolus vulgaris L.) is an essential legume crop in Ethiopia with the potential to contribute to the agricultural system and food security. Since limited productivity is one of the main problems in the study region, stability analysis is essential to enhance productivity by identifying superior genotypes. Thus, this study was conducted to identify common bean genotypes that perform best and are stable at diverse agroecologies. The experiment was carried out on twenty-five small-seeded genotypes grown at four agroecologies for 2021–2022, using a triple lattice design. Evaluation was conducted on nine quantitative traits related to yield. To analyze the performance and stability of the genotypes, analysis of variance (ANOVA), AMMI (additive main effects and multiplicative interaction), AMMI stability value (ASV) rank, WAASB (weighted average of absolute scores biplot), genotype selection index (GSI), and GGE biplot analysis were used. The ANOVA revealed highly significant (p < 0.001) effects of genotypes, environment, and genotype-by-environment interaction for all traits, except the nonsignificant environmental effect for plant height and hundred seed weight. The result of AMMI indicated that Alemtena and Negele Arsi were stable environments and identified G22, G24, and G21 as stable genotypes. However, the GGE identified the mega-environments and best yielding common bean for each environment. The other statistical model, WAASB, identified Mieso as the most representative and discriminating environment, and GSI considered G11, G21, and G24 as desirable genotypes. Both AMMI and ASV identified G18, G21, and G24 as stable genotypes across the tested areas and are recommended for mega-environment production, and Alemtena as an ideal location for the selection of common bean genotypes, since it shows high representativeness and discrimination ability.

Sorghum [Sorghum bicolor (L.) Moench] is an important crop in Ethiopia, especially in lowland areas where drought stress is a major issue. Despite its tolerance, sorghum is susceptible to water-deficit stress during certain growth stages. To identify drought-tolerant genotypes and traits/mechanisms contributing to drought tolerance, a study evaluated 225 sorghum genotypes and assessed the variability, heritability, and genetic advance of these traits using a simple lattice design under stress and non-stress conditions. The analysis revealed significant differences in all traits under both conditions. Drought had a notable impact on various aspects of plant growth, including flowering, maturity, grain yield, and physiological traits such as chlorophyll content and canopy temperature. The study also found moderate to high genetic variation, genetic advance, and heritability for grain yield per panicle, panicle weight, plant height, panicle length, straw yield, and aboveground biomass under both environments. Additionally, grain yield had a positive correlation with 1000-kernel weight, aboveground biomass, harvest index, and grain yield per panicle under both conditions. These traits therefore deserve more attention in future breeding programs aimed at developing drought-tolerant sorghum varieties. The study underlined that morpho-physiological diversity in the studied material is shaped by genotypes, and it could be utilized for variety development and germplasm conservation programs aimed at improving drought tolerance in sorghum.