Agrosystems, Geosciences & Environment最新文献

Anthropogenic activities have increased CO₂ emissions, elevating global temperatures and disrupting rainfall patterns, thus affecting crop productivity. This study examines the photosynthetic performance of Zea mays under elevated temperatures (25°C and 30°C) and CO₂ levels (400 and 700 ppm) in two cropping systems: monoculture and an agroforestry system combining Z. mays with Neolamarckia cadamba. The experiment consisted of three water treatments: P1 (low rainfall), P2 (normal rainfall), and P3 (high rainfall), each with four replicates, giving a total of 12 pots per cropping system and 36 pots overall across the three experimental conditions. Key photosynthetic parameters measured were CO₂ assimilation rate (A), stomatal conductance (Gs), transpiration rate (E), and water use efficiency. Results revealed that Z. mays in the agroforestry system under normal rainfall, 25°C, and 700 ppm CO₂ recorded the highest net assimilation rate. This is likely due to favorable microclimatic conditions provided by the tree canopy, including better moisture retention and reduced heat stress. In contrast, the lowest photosynthetic performance occurred under low rainfall (P1), higher temperature (30°C), and ambient CO₂ concentration (400 ppm). Under these stress conditions, stomatal conductance declined significantly, restricting CO₂ uptake and reducing photosynthetic efficiency. These findings suggest that agroforestry systems could help mitigate the negative impacts of climate change on crop productivity. Integrating trees with crops could enhance photosynthetic performance under future climate scenarios, supporting sustainable agriculture and food security.

Little is known about the sustainability of an intercropping system comprising finger millet (Eleusine coracana) and pigeon pea (Cajanus cajan). We therefore sowed both cover crops and the above crops over 3 years in a seed mix of 8:2 by weight to assess their effects on soil properties, yield potential, and energy-use efficiency. Treatments consist of tillage intensity-conventional, reduced, or no tillage in combination with the cover crop horse gram or lablab bean versus no cover crop. Averaged over 3 years, conventional tillage required energy inputs 12% higher than reduced tillage and 4% higher than those without tillage. The sustainable yield index (89.6%) was highest in conventional tillage with horse gram as the cover crop with a mean of 51.6% and a variation of 42.3%. This combination also improved soil quality, although the energy index was greater under reduced tillage than under no-tillage or conventional tillage. In the wet year (2019), we had higher soil quality index values (8.45–9.97) than in the dry years (2018) (2.50–3.02). The right combination of a cover crop and the intensity of tillage may confer substantial environmental benefits with only minimal detrimental effects on yield.

In recent years, the cultivation area and consumption of quinoa (Chenopodium quinoa Willd) have increased in the country due to its nutritional properties and ability to grow in adverse conditions. Based on climate change scenarios, long periods of drought are expected, which emphasizes the need for planting and developing new plants that are adapted to these conditions. Quinoa's morphological, biochemical, and physiological responses to nanoparticle Fe and Zn foliar treatment during drought stress were examined. Quinoa development was also compared to zinc and iron. With nutrient supplementation, a 2019 drought experiment assessed quinoa growth and quality. The Giza1 cultivar of quinoa was evaluated for its morphological, biochemical, and physiological parameters. The experiment studied three factors: (1) Foliar application of different micronutrient combinations (control, Fe(as FeSO₄), Zn (as ZnSO₄), Fe+Zn, nano-Fe, nano-Zn, nano-Fe+nano-Zn); (2) Application timing at two reproductive stages (50% flowering and 100% flowering); and (3) Drought stress at two levels: control (irrigation at soil moisture potential of field capacity) and stress (irrigation at soil moisture potential of −9 bar). Drought stress greatly reduced plant height, main and lateral branch numbers, leaf number, inflorescence length, leaf, stem, and seed dry weight, wet and dry plant weights, and seed output. Foliar fertilizer increased plant height, main and lateral branch numbers, leaves, inflorescence length, stem, seed dry weights, and plant wet and dry weights. Iron and zinc nanoparticles were better nutrition. Drought stress affects quinoa production less with fertilizer. Also most metrics were negatively affected by drought stress; however, foliar nano-Fe and nano-Zn at 50% flowering minimized its negative effects. High protein, proline, soluble carbohydrates, water, photosynthetic pigments, antioxidant enzyme activity, and low malondialdehyde. Drought stress-application time-nutrient correlations were significant in most parameters. At50% blooming, nano-Fe and nano-Zn treatments had the highest protein, proline, soluble carbohydrate, and antioxidant enzyme levels under drought stress.

Taro (Colocasia esculenta (L.) Schott) is one of the neglected root crops with great potential for ensuring food security. Nigerian taro genetic diversity has been rarely reported, particularly using single-nucleotide polymorphism (SNP) markers. The objective of the present study was to determine the genetic diversity of taro accessions based on agro-morphological traits and Diversity Arrays Technology sequence (DArTseq) SNP markers. Twenty-five accessions collected from five states in Nigeria were used in the study. A field experiment was conducted at Ebonyi State University during the 2020 and 2021 cropping seasons using a 5 × 5 lattice design. Sequencing was performed at Biosciences Eastern and Central Africa (International Livestock Research Institute), Nairobi, Kenya. The results for qualitative traits showed significant (p < 0.05) differences among the accessions, with a mean Shannon–Weaver diversity index (H′) of 0.68. Most quantitative traits also showed significant differences among accessions. Genetic cluster analysis indicated the formation of two major clusters and confirmed the existence of variability among accessions. The polymorphic information content of markers ranged from 0.48 to 0.49. The taro population gene diversity/expected heterozygosity (He) ranged from 0.24 to 0.26, while the observed heterozygosity (Ho) ranged from 0.42 to 0.45. Analysis of molecular variance revealed high genetic variation among individuals within populations (86.90%) but low genetic variation among populations (13.10%). Therefore, breeding strategies should focus on exploiting variation within populations rather than between them. The findings of this study provide a foundational resource for the conservation, management, and utilization of these genetic resources to develop improved taro cultivars in Nigeria and similar agroecologies.

Pecans [Carya illinoinensis (Wangenh.) K. Koch] are widely cultivated in the semi-arid and arid regions of New Mexico and Texas, where irrigation relies heavily on the Rio Grande River and brackish groundwater. This study evaluated the impact of these water sources on soil physicochemical properties, nutrient availability, and pecan tree performance across six orchards along the Rio Grande in southern New Mexico and western Texas over two growing seasons. Soil samples were analyzed for texture, ion concentrations, sodium adsorption ratio (SAR), electrical conductivity (EC), and pH. Pecan performance was assessed using stem water potential (SWP) and leaf and kernel nutrient concentrations. Soil texture significantly influenced magnesium (Mg), calcium (Ca), and sodium (Na). The highest SAR (11.75) and EC (6.21 dS/m) were observed in loamy soil at Fabens 2, with pH ranging from 7.3 to 7.5. SWP values ranged from −12 to −14 bar in clayey soils and −10 to −12.5 bar in sandy soils. Leaf and kernel nutrient concentrations varied by location, with the highest zinc (Zn) levels in Fabens 2 (leaf: 160 mg/kg) and Derry (kernel: 120 mg/kg), and peak phosphorus (P) in Derry (leaf: 1195 mg/kg) and Las Cruces (kernel: 2858 mg/kg). Loamy soils with higher EC supported elevated Zn, Na, and potassium (K) in leaves, while sandy loams promoted higher Mg and kernel nutrient accumulation. In leaf, Zn decreased with Mg and K, while Na was strongly antagonistic to Ca and Mg. In the kernel, P, Mg, Ca, and K increased together. Zn tended to decline as P and K were raised. Seasonal variations showed greater Mg, Ca, and Na in leaves in October, while P and Ca in kernels peaked in 2015. A massive increase in nutrients from soil to leaf, then a decrease in the kernel. These findings underscore the need for site-specific nutrient management and regular soil and tissue testing to optimize fertilization and mitigate imbalances.

Participatory variety selection (PVS) offers a practical alternative to researcher-led breeding by directly involving farmers in evaluating and selecting crop varieties that meet their production needs and local conditions. This study assessed the agronomic performance and farmer preferences for eight released teff varieties and one standard check during the 2021 and 2022 cropping seasons in Shebel Berenta and Dejen districts of the East Gojjam Zone, Ethiopia. Mother-and-baby trials were established using a randomized complete block design at Farmer Training Centers. Significant variation was observed among varieties across years and locations. Boset produced the highest grain yield in Shebel Berenta (3285 kg/ha), yielding 21.00% more than the standard check, Quncho, while in Dejen, it produced 2256 kg/ha, a 26.80% advantage over the standard check. Farmers identified grain yield, panicle length, and tillering ability as the most important selection criteria. Boset was the top-preferred variety in both locations, followed by Dagem and Quncho in Shebel Berenta, and Felagot and Quncho in Dejen. The findings demonstrate the practical value of PVS in generating varieties that align with farmers’ priorities, thereby enhancing the likelihood of adoption and ensuring better matching between breeding objectives and local agronomic and market needs.

Peppermint (Mentha piperita) is a perennial herb valued for its menthol-rich oil and requires high nitrogen (N) inputs for its irrigated production. Optimizing N management can reduce nitrous oxide (N₂O) emissions, a potent greenhouse gas associated with fertilizer N input. A 2-year experiment (2022–2023) was conducted in western Nebraska to evaluate the effects of N fertilizer sources (urea and polymer-coated urea; PCU) applied at different rates on peppermint yield and N₂O emissions. Application rates were lower in 2022 than in 2023 due to transplanting and herbicide injury issues. Therefore, dry matter yield was lower in 2022 (3.38–3.84 Mg ha⁻¹) than in 2023 (7.56–14.11 Mg ha⁻¹). In 2023, PCU at the highest rate (332 kg N ha⁻¹) had a greater peppermint dry matter yield than all other treatment combinations except for urea at the same rate. In 2023, yield did not vary with N source, except at the low rate, where PCU had a greater yield (12.14 Mg ha⁻¹) than urea (9.31 Mg ha⁻¹). In both years, urea had greater N₂O emissions than PCU, except for the lowest N rate (34 kg N ha⁻¹) in 2022. Nitrous oxide emissions varied by N rates for urea but not for PCU. Fertilizer-induced emission factors (FIEF) were within the range of the Intergovernmental Panel on Climate Change (IPCC) disaggregated emission factor of 0.5% (0.0%–1.1%) for dry climates. Nitrogen source-specific FIEF disaggregation might narrow the current IPCC uncertainty range.

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.