Agrosystems, Geosciences & Environment最新文献

The testing of durum wheat (Triticum turgidum subsp. durum) varieties in different irrigated environments is critical for determining the stability of their performance and adaptation. In this study, 12 popular and newly developed durum wheat varieties were examined in eight irrigated locations with the purpose of investigating genotype–environment interaction and their effect on Ethiopian tetraploid wheat yield stability across diverse environments. The field experiment has two replications with a randomized complete block design. Multivariate (analysis of variance, additive main effect and multiplicative interaction [AMMI], and genetics, genetics × environment [GGE] biplot) and univariate (b_i [regression coefficient], S²_d [deviation from regression], σ_i² [Shukla's stability variance], W_i² [Wricke's ecovalence], YS_i [yield stability statistic], and CV_i [coefficient of variance]) analysis methods were used to identify stable varieties. The AMMI analysis showed that the genetic × environmental interaction was highly significant (p > 0.01), while the genotype and environment variation were not significant. The first two principal component axes (IPCA1 and IPCA2) were highly significant (p > 0.01) and contributed 79% of the total GE interaction. Univariate statistical models indicate that Bulala is a stable, high-yielding variety that can adapt to various environments. GGE biplot analysis revealed that the eight test environments were clustered into three mega-environments, ranked Bulala as the most stable variety across diverse environments. The results of the combined mean analysis, multivariate and univariate models revealed that Bulala is a high yielder (3.46 tons ha⁻¹) and stable variety across all test environments, while Mukiye variety has a high yield (3.43 tons ha⁻¹) but is not as stable or adaptive to multiple locations. As a result, Bulala was recommended for further demonstration and popularization in test locations and places with similar agroecologies under irrigation.

The consolidation of oil sands tailings is a cost- and time-consuming process that requires treatment via active (e.g., centrifugation) and passive (e.g., self-weight consolidation) methods. The use of plants to dewater tailings is a promising concept and has previously been evaluated using agronomic grass species in greenhouse studies. This greenhouse study evaluated the short-term survivorship and growth of 32 upland and lowland native plant species (12 forbs, 14 graminoids, and six woody plants) in centrifuged tailings and benchmarked their performance against reclamation soil and undisturbed forest soil. All plant species were propagated from seed and transplanted as seedlings into containers filled with one of the three substrates. After 42 days, the height (woody species only) and total aboveground biomass were determined for all living plants. As expected, the mortality of seedlings in tailings was higher than plants grown in the other two substrates. Graminoid species, regardless of species community type (wetland or upland), had higher survival probabilities and growth compared to forb or woody species across all substrates. Of forbs and woody species evaluated, Geum aleppicum and Populus tremuloides showed the most promise amongst the upland species, and Rumex occidentalis was the wetland equivalent.

The integration of aquaculture and agriculture in arid and semi-arid environments is crucial for maximizing water and land productivity, especially considering the increasing global water scarcity and the simultaneous use of water for crop and fish production. A greenhouse study was conducted to determine the effects of fish effluent on the growth, yield parameters, and yield of cowpea (Vigna unguiculata). The experiment involved 13 fertilization treatments, including three types of irrigation water (river water—control, Nile tilapia (Oreochromis niloticus), African sharp-toothed catfish (Clarias gariepinus), four fertilizers (poultry, cattle, and sheep manures at 10 t ha⁻¹), recommended rate of inorganic fertilizer (150 kg ha⁻¹ of NPK 6-20-10), and six mixed treatments with fish effluent and 50% of the applied rate of manure alone (5 t ha⁻¹). The combined use of C. gariepinus effluent + 50% poultry manure significantly increased stem diameter, nodules per plant, pods per plant, and seed yield compared to NPK treatments. The shortest days to reach 50% flowering were obtained with the effluent of O. niloticus + 50% sheep manure, C. gariepinus/O. niloticus + 50% poultry manure, and 10 t ha⁻¹ poultry manure. However, fertilization treatments did not significantly influence the number of branches, pod and root length, number of pods per plant, 100-seed weight, and leaf chlorophyll concentrations. This study suggests that fish effluents, when combined with manure, can improve plant growth and seed yield, providing a cost-effective alternative to inorganic fertilizers for smallholder farmers.

Potassium (K) nutrition and drought stress affect soybean (Glycine max (L.) Merr.) vigor and productivity through the combined impacts on water regulation. A study was conducted with soybean grown in 18.9-L buckets under a rain out shelter to determine how the interaction between these crop stresses at various growth stages influences the crop leaf K concentration, biomass production, total K uptake (TKU), grain yield, and temperature of the uppermost fully expanded trifoliate. Treatments included soybean grown with and without preplant fertilizer K, soil moisture at 50% (drought) or 80% (well-watered) field capacity, imposed drought during vegetative growth (V3–V7), flowering (R1–R3), pod development (R4–early R6), and seed development (R5–mid-R6) on two different silt loam soils. Widespread K deficiencies were observed during the study across all treatments. Drought stress significantly (p < 0.05) reduced the TKU, aboveground biomass production, and grain yield. The crop growth stage when drought stress was imposed was a significant factor, with greater reductions in plant response parameters when stress was imposed during reproductive growth. Preplant fertilizer K increased trifoliolate K concentrations and TKU in drought conditions, but did not increase the grain yield of well-watered soybean. Leaf temperature increased when under drought stress compared to well-watered soybean (p < 0.0001) but the impact of crop K nutrition status on leaf temperature was inconclusive because of widespread K deficiencies. Results emphasize the complexity of the interactions between K nutrition and drought stress in soybean, as drought stress impeded K uptake, exacerbated K deficiencies, and limited yield.

Little is known about the relative impact of lighting duration and light intensity on lettuce production, as well as whether daily light integrals (DLIs) play a significant role during different plant growth stages. Four DLIs were tested: 8.64, 11.52, 12.96, and 17.28 mol m⁻² day⁻¹ as supplemental lighting, which were obtained from a combination of supplemental light intensities at 200 and 300 µmol m⁻² day⁻¹ for 12 and 16 h. Sunlight was used as control. A direct correlation was observed between DLIs and yield, total fresh weight, and total dry weight. Under supplemental lighting, relative growth rate (RGR) increased due to an increase in net assimilation rate (NAR) rather than in leaf area ratio (LAR). Plants in the seedling stage were more sensitive to an elevation in DLI than in the head stage. This was confirmed by a greater increase in NAR compared to their corresponding control under the same DLI. Increasing DLI also improved lettuce quality via reducing nitrate and increasing protein content. Higher DLIs (12.96 and 17.28 mol m⁻² day⁻¹) led to a decrease in maximum quantum yield of photosystem II and an increase in performance index. In conclusion, manipulating RGR through NAR adjustments proved to be more effective than changes in LAR, and adjusting supplemental DLI at each stage was necessary to achieve a larger NAR and, consequently, a larger RGR.

The interaction between nitrogen (N), phosphorus (P), and potassium (K) fertilizers significantly impacts the uptake of micronutrients in corn, influencing their availability in soil and uptake by plants. Understanding the interaction of macro- and micronutrients is a prerequisite to targeting nutrient balance in crop production. Therefore, a 2-year field experiment was conducted to determine the effect of NPK fertilization on micronutrient uptake of rain-fed corn (Zea mays L.). A randomized complete block design was employed with 12 treatments replicated three times. Different combinations of N, P, and K fertilizer rates were investigated for micronutrient concentration and uptake in rain-fed corn. Findings revealed the order of nutrient accumulation in corn plants: iron (Fe) > manganese (Mn) > zinc (Zn) > copper (Cu). Nitrogen application influenced nutrient concentrations and uptake. Increasing N rates increased micronutrient concentrations in corn grain, except for Cu. Interestingly, Cu content in grains exhibited no correlation with nutrient supply, biomass, or other concentrations. As the N application rate increased, micronutrient content increased at early growth stage and physiological maturity. Phosphorus application showed negligible impact on grain micronutrient concentration and uptake. However, K application notably increased Mn, Fe, and Cu uptake in grains. This study underscores the need to consider not only grain yield but also nutritional quality when determining optimal NPK rates in rain-fed corn cultivation.

Successful improvement of stable genotypes is dependent on the interaction of genotype with environment, which has a great influence on breeding new barley (Hordeum vulgare) varieties. The main objectives of this study were to (1) evaluate the effectiveness of drought tolerance indices for the selection of drought-tolerant barley genotypes, (2) identify stable high-yielding genotypes in variable environments, and (3) survey physiological traits of five contrasting genotypes under water deficit. In this experiment, 18 spring barley genotypes were evaluated under two moisture regimes (normal and deficit irrigations) for 2 years during the crop periods of 2022–2023 in Varamin Agriculture Experimental Station. In order to identify drought-tolerant barley genotypes in response to water deficit, GGE (genotype and genotype by environment interaction) biplot and AMMI (additive main effects and multiplicative interaction) analysis, stability parameters, and drought indices under water deficit and normal condition were used. Also, physiological traits in three tissues (leaf, penultimate, and peduncle) were measured. Based on our results, AMMI and GGE biplot analysis revealed that the G15 genotype was superior to other genotypes under water-deficit condition. Based on the physiological traits, the G3 and G15 had higher chlorophyll content and carotenoids than other genotypes under water deficit as compared to normal condition. Our results demonstrate the efficiency of the stability evaluation techniques to select genotypes that are high-yielding and responsive to drought stress condition.

Winter cover crops (CCs) have the potential to reduce phosphorus (P) loss by temporarily fixing P into CC biomass. A field experiment with no-tillage (NT) and conventional tillage (CT) was used to study the ability of different CC species planted after corn (Zea mays L.) and soybean (Glycine max L.) harvests to reduce the P availability in soil solution. The effect of three crop rotations (corn–no CC–soybean–no CC [C–S], corn–cereal rye (Secale cereale)–soybean–hairy vetch (Vicia villosa) [C–R–S–HV], corn–cereal rye–soybean–oats (Avena sativa)+ radish (Raphanus sativus L.) [C–R–S–OR]) and two tillage (NT and CT) treatments was determined on soil available P and soil solution P content through pan (A horizon) and tension (100-cm depth) cup lysimeters. The experiment was set up as a randomized complete block design with tillage as a split factor with three replicates. Over the study period, incorporating hairy vetch in C–R–S–HV rotation reduced the Mehlich-3 P content in soil by 26%–29% compared to the C–S and C–R–S–OR rotation. Both CC rotations (C–R–S–HV and C–R–S–OR) were effective in reducing dissolved reactive P (DRP) concentration in pan and tension cup lysimeters compared to the C–S in both CT and NT systems. However, these results varied with CC species grown and seasonal variability in precipitation. A significantly lower DRP load with crop rotation and tillage treatments was observed mainly during the CC growing season. During the study period, crop rotations with reduced labile soil P content and DRP loss were ranked in an order of C–R–S–HV > C–R–S–OR > C–S. Overall, this study showed that CCs have the potential in both CT and NT systems to significantly reduce P in soil and soil solution, and these effects are resilient to a wide range of precipitation conditions.

The viability of modern horticulture heavily relies on adopting sustainable practices. Understanding soil spatial variability on heavy clay soils and its impact on young trees is crucial to design suitable soil and water management strategies that guarantee the sustainability of orchards. The objective of this study was to assess in an orchard with heavy clay soils of the Riverine Plain, NSW, the impact of soil spatial variability on the development of young almond (Prunus dulcis (Mill.) D. A. Webb) trees and evaluate the use of remote and proximal sensing tools for identifying threatening factors for the sustainability of the crop. Soil and aerial surveys were used to assess the soil and crop spatial variability in an 8.3-ha irrigation block. The site was divided into five areas based on apparent electrical conductivity (EC_a) measurements where soil samples were collected. Tree growth, soil, and plant water status were monitored in two contrasting areas in EC_a. In the first year of study, a significant and positive correlation was found between EC_a and percentage of ground canopy cover. Soil analysis and soil moisture monitoring revealed that high values of exchangeable sodium percentage, which are indicative of sodic soils prone to dispersion, and limited water infiltration were the cause of the reduced tree growth in areas with low EC_a. The impact of soil spatial variability on tree growth decreased in the second growing season due to weather and water management factors that influenced soil water content. This study showcases the usefulness of remote and proximal sensing in assessing potential soil-spatial-related issues in newly established orchards as well as the impact soil spatial variability can have on tree development in the first years after planting.

Biological nitrogen fixation by rhizobia bacteria plays a pivotal role in sustainable agriculture by converting atmospheric nitrogen into a form that plants can assimilate, thereby reducing the need for synthetic fertilizers. This process can be dramatically reduced by various abiotic stressors. Native rhizobia strains, which are naturally occurring, may be better adapted to the local soil and climatic conditions, making them more resilient to stress factors such as drought, salinity, temperature extremes, and pH variations compared to commercial strains that may have been developed in and for different environments. This study aimed to compare the efficacy of native rhizobia species with a commercial inoculant and uninoculated controls in maintaining nitrogen fixation under induced stress by delayed planting in field peas over two growing seasons (2021 and 2022) in central South Dakota. Our findings indicate that native rhizobia, while not outperforming the commercial inoculant, demonstrated competitive nitrogen fixation capacities. Overall, total nitrogen fixation was not statistically different between a commercial inoculant and native rhizobia formulations. Planting date emerged as a significant factor influencing nitrogen fixation, with later planting substantially reducing overall effectiveness. These results highlight the potential of native rhizobia as an alternative to commercial inoculants and underscore the need for increased screening throughput and improved methods to assess rhizobia efficacy and nodule competition in field settings.