Agrosystems, Geosciences & Environment最新文献

Sulfur (S) is necessary for amino acid production, disease resistance, protein synthesis, and nitrogen assimilation in plants. We tested the performance of three S sources (magnesium sulfate [EPTOP], gypsum, and ammonium sulfate [AS]) at two different rates (45 and 90 kg S ha⁻¹) on soil S availability, vegetative indices (VIs), above- and belowground biomass (BGB), and potato (Solanum tuberosum L.) S uptake. For VIs such as normalized difference vegetative index, normalized difference red-edge index, and chlorophyll content, the maximum values were reported when gypsum and EPTOP were applied compared to AS. These differences were decreased later in the season. Significant interaction effects were reported among sites, sampling events, and sites and S sources for aboveground biomass (AGB). Similar trends were reported for the BGB, where the significant interaction effect was reported among the S sources and sampling event and S sources and sites. The AGB S uptake was affected due to the sites and sampling event. However, BGB S uptake was influenced by the interactive effect of S sources, sites, and sampling events. The VIs did not have a significant association between soil S concentration and AGB S uptake. It was found that the field history had a notable effect on the crop responses to variable S sources. In conclusion, applying S rates and sources has distinct responses, which depend on soil history and chemical properties, and that should be considered when making choices for S application in potatoes.

Fusarium head blight (FHB) is a devastating disease reduces wheat yield and quality. This study was aimed to evaluate wheat varieties' responses to spray inoculation with Fusarium graminearum mixture isolates under greenhouse conditions. The treatments were laid out in a randomized completely block design with three replications using 24 bread wheat varieties registered in Ethiopia. The varieties inoculated with mixed inoculum derived from four pathogenic isolates of F. graminearum that had been isolated from wheat kernels. Disease severity was evaluated using a 1–9 scale based on the proportion of bleached spikelets, and the area under disease progress curve (AUDPC) was determined from the disease severity data. At harvest, the kernel weight reduction was determined in comparison to the control. The evaluated traits were significantly interrelated and showed high and significant variation among (p < 0.0001) wheat varieties. Disease severity index among the varieties varied from 29% to 72%, while AUDPC varied from 326%- to 1010%-days. The disease progress rate of the Kingbird variety inoculated with F. graminearum was the slowest (0.0191 units day⁻¹), whereas Ogolcho had the fastest disease progression rate (0.0581 units day⁻¹). Kingbird, Wane, and Limu were moderately resistant, with lower disease severity, AUDPC, and a reduction in 1000-grain weight and grain weight per spike. Dereselgne, Dambal, and Ogolcho varieties were highly susceptible, with the greatest grain weight per spike reduction (53.2%, 41.4%, and 37.4%) and 1000-grain weight reduction (41.5%, 42.8%, and 37.5%), respectively. The results implied that there were different levels of FHB resistance in Ethiopian bread wheat varieties. Although current greenhouse evaluation of varieties gives encouraging results, field testing is required to confirm the current findings.

Phosphorus (P) can be recovered from wastewater and used as an alternative fertilizer, namely, struvite [MgNH₄PO₄·6(H₂O)]. However, the soil mobility of wastewater-derived P and other nutrients needs to be evaluated. The objective of this study was to compare the vertical distribution of water-soluble (WS) soil P and other nutrients from a synthetic-wastewater-derived electrochemically precipitated struvite (ECST) to that from a chemically precipitated struvite (CPST), triple superphosphate (TSP), monoammonium phosphate (MAP), and a control in six soils from Arkansas (AR; loam [L] and silt loam [SiL]), Missouri (MO; SiL 1 and SiL 2), and Nebraska (NE; sandy loam [SL] and SiL). A column-leaching experiment was conducted with the six soils and five fertilizer-P treatments. Water-soluble (WS) P from the two struvite materials generally did not differ (p > 0.05) and was similar to that of MAP in the depths of 0–3, 3–6, and 6–10 cm, but was greater than that of TSP in the top 6 cm in four of the six soils. WS P from CPST in the MO-SiL 2 and NE-SL soils (6.6 and 12.7 mg kg⁻¹, respectively) was larger than that from ECST, MAP, and TSP. In the AR-L and MO-SiL 1 soils, TSP was the only fertilizer-P source that had increased WS P concentrations in the top 6 cm relative to the other fertilizer-P sources. Results showed that ECST-derived, WS P had similar soil profile distributions in the top 10 cm, suggesting that ECST will be equally protective of environmental health and leachate quality across multiple soil textures as other common fertilizer-P sources.

Although Texas is not widely known for organic production, it is responsible for most organic peanut production in the United States. When managed effectively, this can be a lucrative practice due to consumer demands. However, farmers pursuing organic management must undergo a 3-year transition period to obtain United States Department of Agriculture certification, which is often associated with depressed yields. The objective of this study was to measure the impact of organic management and cover crop selection on biological indicators of soil health during the second year of transitioning to an organic cotton–peanut rotation in West Texas. We conducted a field study at two locations, and soil health indicators including in situ respiration, carbon mineralization, enzyme activities, and phospholipid fatty acids (PLFAs) were measured. The use of a cover crop resulted in generally greater biological activities compared to the fallow after only one cover crop rotation, representing early elevated biological activities under plots treated with a cover crop. However, cover crop species selection typically does not affect soil biological parameters. Cover crop use also did not contribute to yield losses when compared to a fallow treatment. When comparing organic management to conventional management, both sites experienced elevated PLFA counts under organic management. Importantly, results indicated that although reduced peanut yields could be expected under transitional organic management, this was not cover crop species-specific, nor was it a guarantee. Given the economic risk of organic management for farmers, this study will benefit producers deciding whether to pursue organic production and cover cropping.

In recent years, many alternative bio-waste-based fertilizers have been proven to have a beneficial effect on plant nutrition. These also include wool pellet, whose comprehensive evaluation of synergistic effects on plant development and soil biological activity is still a limited field of investigation. To address this, we explored the potential of combining soil inoculations and N-rich wool pellet as ecologically sound alternatives to N fertilizers. In a pot experiment, we investigated the effect of Azotobacter vinelandii, the Trichoderma harzianum T34, and wool pellet, individually and in combination, on the growth and nitrate uptake of the test plants, as well as on the biological activity and permanganate-oxidizable carbon of the sandy soil with low organic matter content. The combination of T. harzianum + wool pellet showed the highest biological activity and permanganate-oxidizable carbon content, while the untreated control plants exhibited the lowest values. The treatment combination of wool pellet and A. vinelandii exhibited the highest nitrate uptake by plants. Measuring the concentration of photosynthetic pigments, net photosynthesis, transpiration rate, stomatal conductance, and total dry biomass, we found that the treatments led to a significant improvement in the photosynthetic intensity of lettuce plants. These results suggest that wool pellet served as a significant source of N and that their biological activity plays a key role in improving plant parameters. Moreover, the combination of microbial inoculants and wool pellet effectively increases N use efficiency in plant growth.

Food crop productivity is still low because of the decline of soil fertility in Ethiopia, particularly in north-western Amhara. Fine-tuning the source and rate of nutrients is required to solve soil fertility problems along landscape positions. Therefore, this study was initiated to investigate the need to apply selected nutrients to tef and wheat in acidic soils. This nutrient omission study was conducted in 74 farmers’ fields of Gozamen and Machakel districts. The omitted nutrients were sulfur (S), zinc (Zn), and boron (B). Potassium (K) was added, consisting of N, P, K, S, Zn, and B (All+K). Nitrogen plus phosphorus (NP) and no fertilizer treatments were used as positive and negative controls, respectively. Furthermore, 50% and 150% of the All+K treatments were also included. The finding revealed that the application of different nutrient types at variable rates had a significant role in the grain and biomass yield of both test crops in the acidic soils. No tef yield and the lowest yield of bread wheat were obtained from the no fertilizer application treatment. The application of All+K had no significant yield advantage compared to NP fertilizer alone. This implies that N and P are the most yield-limiting nutrients to produce tef and bread wheat, whereas KSZnB nutrients are not yield limiting. Therefore, refining the rates of N and P in acidic soils is needed for the economical use of fertilizers. Finally, applying blended fertilizers without empirical evidence is not recommended for smallholder farmers in the study area.

Soil health assessments aim to quantify soil health status using indicators linked to ecosystem services such as yield, nutrient cycling, water cycling, or carbon storage. Many indicators are related to soil biological processes, which can be challenging to interpret because they are sensitive not only to management, but also to nonmanagement variables such as soil inherent properties, topography, and climate. Existing studies address this challenge by grouping similar soils by taxonomy, geography, or a combination of these and other variables for soil health assessment. We investigated whether grouping soils based on multiple quantitative topsoil properties could be an alternative to taxonomic or geographic groups. We used an unsupervised classification algorithm, k-means, to cluster publicly available soil and climate data for Minnesota. Clustering into eight conceptual groups (“clusters”) based on 10 topsoil properties was determined to be the optimal algorithm output. We evaluated the ability of our soil clusters and other grouping methods to explain variance in eight soil health indicators. We found the combination of Major Land Resource Area (MLRA) and soil cluster performed best, explaining as much or more variance than other groupings for five of the eight indicators. The clusters distinguish zones of topsoil variation at the field scale, and MLRAs account for broader scale variation in climate and other landscape factors. The approach we describe is flexible and could be applied at different locations and scales to produce conceptual soil groups and associated maps to support soil health test sampling and interpretation at the field scale.

This systematic review addresses the difficulties of cultivating under variable environmental conditions and explores the growing importance of chili peppers (Capsicum annum L.) in worldwide agriculture. It emphasizes the use of enclosed growing systems as a workable way to increase crop yields of chilies. The needs of various chilies in these systems highlighting the significance of sustainability and resource efficiency for the best possible yield, quality, and financial sustainability. Shading is a crucial tactic to mitigate the adverse effects of sunlight and high temperatures, supporting healthier plants and regular fruit development. The study also looks into greenhouse cultivation to shelter plants from the weather and achieve higher yields, better development rates, and better-quality fruit. This thorough analysis fills a research gap, offers helpful recommendations for maximizing production, and is an invaluable tool for practitioners and scholars studying enclosed chili agriculture.

Cover crops can be a great addition to agricultural systems to improve soil health and nutrient cycling. One of the many qualities that cover crops possess is recovering residual nutrients. This study was established to estimate daikon radish (Raphanus sativus var. Longipinnatus) nitrogen (N) uptake, partitioning, and accumulation in a short time in Florida conditions. In greenhouse conditions, two Florida sandy soils were planted with daikon radish with three N rates (0, 50, and 101 kg N ha⁻¹ as urea) following a randomized complete block with four replications. The treatments were organized in a two-by-three full factorial arrangement with the three N fertilizer rates. Biomass accumulation, N uptake, and partitioning into shoots and roots were estimated, and residual soil N was calculated. Increasing the amount of N applied to daikon radish plants did not increase biomass production or N accumulation in the shoots and roots of the plants. Daikon radish plants grown without N fertilization were able to produce a similar amount of biomass as those with N applications in their early growth stage. This suggests that daikon radish has the potential to adapt to the sandy soils of Florida and could efficiently utilize the residual soil N. This study shows the potential use of daikon radish as a cover crop in the row middles of citrus groves. The findings suggest that daikon radish plants could thrive in these unfertilized areas and offer promising benefits to the citrus orchards in terms of providing ground cover and additional advantages.