Agrosystems, Geosciences & Environment最新文献

Water-seeded rice (Oryza sativa L.) in California is produced near growing urban centers and a variety of neighboring high-value crops, which make water quality a paramount concern because of potential herbicide residue contamination in downstream surface waters. Pendimethalin is a potential herbicide for use in California water-seeded rice. A study was conducted to characterize pendimethalin's dissipation in water of a water-seeded rice field. A capsule suspension (CS), emulsifiable concentrate (EC), and granule (GR) pendimethalin were applied onto flooded rice plots at 1.1, 2.3, and 3.4 kg ai ha⁻¹ rates. Water samples were collected periodically and analyzed with an high pressure liquid chromatography tandem mass spectrometry system for residues. Pendimethalin dissipation differed across formulations. The initial sampled concentrations recorded values from 3.0 to 125.6 parts per billion (ppb). First-order dissipation resulted in half-lives for the CS from 2.3 to 3.5 days, the EC from 0.6 to 0.7 days, and the GR from 3.5 to 6.9 days. Pendimethalin use in water-seeded rice is at low risk of contaminating downstream surface waters; however, early sampled residue concentrations could be concerning. The results can assist in generating management tactics like water-holding periods to avoid potential downstream off-target effects and ensure herbicidal activity in the applied area after a pendimethalin application in a water-seeded rice field.

Solutions are needed to address increasing concerns over degraded land and global food insecurity. One solution is to design soil blends that can restore soil quality and fertility. Dredge material has many soil-like properties, which makes it a good candidate for the main component of manufactured soil blends. Questions have arisen over contaminants of concern (heavy metals and polyaromatic hydrocarbons [PAH]) in dredge fines precluding them from reuse. One approach is to remove the fine fraction of dredge to lower the contaminant concentration; however, it may result in a lower quality soil substitute for land reclamation. In this study, soil blends were designed to compare the use of whole dredge to dredge fines (e.g., dredge with silt and clay fraction) and to assess the benefits of compost material, clay, and fertilizer additions. Dredge fines blends led to increases in soil quality, dry matter growth, plant available water, total and active C, potentially mineralizable N, and micronutrients. The addition of compost material led to better soil quality for a vast majority of the tested parameters. Dredge fines were below regulatory standards for contaminants of concern (e.g., carinogenic polyaromatic hydrocarbon and heavy metals), allowing their reuse in soil blends. Removal of fines from dredge decreases the quality of soil blends and should not be removed from dredge material for use as topsoil or in topsoil blends. The 80% (v/v) dredge fines blend with 20% (v/v) additions of compost material resulted in the greatest improvements in the assessed soil health parameters.

Soil erosion is a severe soil degradation problem that endangers the actualization of Sustainable Development Goals. It affects agricultural production by reducing soil fertility via topsoil translocation, leading to soil quality deterioration. A review of soil erosion modeling using the Revised Universal Soil Loss Equation (RUSLE) model shows that Nigeria lags behind other developing countries like Ethiopia despite the massive improvements provided by remote sensing and geographic information system (GIS) technologies. Fewer than 50 articles were found on the Google Scholar search engine that used the RUSLE model for empirical studies on soil erosion. Only four research articles were found on the ScienceDirect website. Additionally, there were differences in the findings from studies across Nigeria. Such disparities were due to differences in the approaches used to estimate key factors in the RUSLE model. Therefore, we recommend that the Ministries of Agriculture and Environment take soil erosion research seriously by adopting proactive soil conservation and management measures. Ensemble models can be used including machine learning approaches rather than focusing mainly on structural intervention. In addition, there should be a harmonized look-up table for the cover management factor and conservation practices factor that fairly represent the various ecoclimatic regions. The limitations to the model's use are highlighted, and a way forward is suggested.

Crop management through site-specific fertility methods is crucial for both economic and environmental benefits. Potato-specific fertilizer has not been fully established in Kenya, and the current fertilizer recommendation has been in place for a long time. A study was designed through soil sampling from small-scale farms to make a soil-based fertilizer recommendation for potato production. Inverse distance weighting interpolation was used to study spatial distribution of pH and major nutrients. Cluster analysis was used to group sampled farms into similar fertility clusters for easier fertilizer recommendations. Spatial distribution maps were identified for the project area. Three and four clusters were established in Meru and Nyandarua counties, respectively, among which three had adequate nutrients for potato production. At least 150 kg N ha⁻¹ is recommended in most of the farms and 160 kg P ha⁻¹ in Nyandarua, while 285 kg K ha⁻¹ was recommended in one of the clusters (nitrogen, phosporus, potassium [NPK] 1:1:1.5). Cluster analysis can be used to enhance fertilizer recommendations. The assumption that K is adequate in tropical soil should not be generalized. Fertilizers in the market with formulations close to the recommended ones should be evaluated for field performances and adjustment of the final potato fertilizer.

Early seed germination significantly influences crop growth and production, prompting the exploration of seed priming as a pivotal technique. Despite the acknowledged importance of faster germination and emergence for successful seedling establishment, oilseed crops like Sinapis alba have received limited attention concerning seed priming methods, unlike cereal and grain crops. This study aimed to bridge this gap by subjecting S. alba seeds to six priming treatments: T1 = control, T2 = distilled water, T3 = NaCl (0.5%), T4 = KNO₃ (0.5%), T5 = CaCl₂ (0.5%), and T6 = Moringa leaf extract at a 1:30 ratio (30 times diluted), to assess their impact on various growth and yield parameters. The data analysis revealed significant effects of seed priming on various parameters, with exceptions in plant height unaffected by seed soaking. Seed priming notably enhanced germination percentage, germination rate index, and seedling vigor index, while reducing mean germination time to emergence significantly. Furthermore, primed seeds exhibited significant increases in seedling fresh and dry weights, crop growth rate, net assimilation rate, root and shoot lengths, leaf area, chlorophyll content, early flowering, branch numbers, pod counts, and 1000-seed weight compared to non-primed seeds. The biological yield was relatively higher in treated seeds. Additionally, seed yield and oil content were found to be higher in primed seeds compared to the control. Among the treatments, KNO₃ along with Moringa, displayed the most desirable outcomes across overall seedling parameters, suggesting their recommendation for effective priming treatments to improve the growth and yield of S. alba.

Finger millet (Eleusine coracana (L.) Gaertn.) is an important cereal crop grown in most parts of Asia and Africa owing to its ability to adapt to stressful environments. The objective of this study was to examine the effect of waterlogging on photosynthesis and growth of finger millet. Plants were subjected to waterlogging by keeping pots filled with water from June 16 (transplanting) until November 12 (harvesting) in 2021 in Tokyo. After being subject to 13 days of waterlogging, net photosynthetic rate (P_n) decreased by 10.1% due to reduced stomatal conductance (g_s), transpiration rate, and relative chlorophyll content (SPAD). From July to September, long-term waterlogging increased P_n in the range of 4.9%–26.3%. The alleviation of high temperature, increase in SPAD and g_s, and other nonstomatal components were implicated as the cause of increased P_n in summer. These findings suggest that the effect of waterlogging on photosynthesis varies with the duration of waterlogging or the growing season. Plant height was significantly reduced by 27.9% during the first 13 days of waterlogging and remained lower throughout the waterlogging treatment than in irrigated conditions. Waterlogging also caused other morphological changes, such as a significant increase in the number of tillers (63.2%) and a 16.7% increase in the number of panicles. Grain yield decreased by 13.6%, but the reduction was not significant. Overall, finger millet has the potential to tolerate waterlogging and is a promising crop for both paddy and field farming.

The effects of gibberellic acid and potassium nitrate on seed emergence and seedling growth of amaranth and Cleome gynandra were investigated in the greenhouse at Marondera University of Agricultural Sciences and Technology. The study was laid out in a factorial layout within a completely randomized design replicated three times. Potassium nitrate (dry seeds, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, and 1%) and gibberellic acid (dry seeds, 100, 200, 300, 400, 500, 600, 700, 800, 900, and 1000 parts per million) were used, respectively. A total of 100 seeds of both crops were planted in each plastic pocket. Seed emergence percentage and vigor index of amaranth and C. gynandra were evaluated. The effects were more pronounced in seeds treated with gibberellic acid than in potassium nitrate. Seed emergence and vigor index of amaranth and C. gynandra seeds treated with gibberellic acid showed a significant difference at p < 0.01, while potassium nitrate showed no significant difference at p > 0.05. The maximum seed emergence percentage of amaranth and C. gynandra was 67.1% and 64.8%, which was obtained in 2022 and 2021, while the lowest was 35.5% and 37.5%, which was obtained in 2021. The highest vigor index I of amaranth and C. gynandrawas 590.3 and 586.2, which was observed in 2022 and 2021, while the lowest vigor index I was 45.2 and 170, which was obtained in 2021 and 2022. The results obtained indicated that the application of gibberellic acid on seeds of amaranth and C. gynandra can alleviate seed dormancy.

Farmland within the Williston Basin of North Dakota was the site of the largest terrestrial oil spill to date in the United States in 2013. Over 3200 m³ of oil was released into the topsoil and subsoil, creating a risk to soil, water, and air resources. The purpose of this document is to provide a summary of results from a 7-year project investigating the impacts of how thermal desorption (TD), the method used to remediate topsoil and subsoil, impacted contaminant reduction, soil function, and plant productivity simultaneously with site remediation. Soil disturbance and TD decreased soil organic matter and microbial communities, resulting in decreased soil function and plant production. However, TD did not reduce soil microbial recovery 4 years after treatment. Blending TD-treated soil with uncontaminated topsoil appeared to minimize these negative effects and promote recovery of soil function. These findings provided critical information to stakeholders in the understanding of soil remediation and reclamation in this region.

Crop yields are adversely affected by nitrogen (N) losses in humid subtropical regions. This study was conducted to determine whether N dynamics could be manipulated through planting geometry and fertilizer placement. The effects of irrigation (irrigated and rainfed), row pattern (single- and twin-row), and N placement (surface dribble, one knife, two knives, and control) on corn (Zea mays L.) productivity and N use efficiency were investigated at Leland, Mississippi, on a Bosket very fine sandy loam. The total N rate was split into two equal halves of 128 kg N ha⁻¹ at V2 and V6 growth stages. The effects of row pattern and N placement were consistent between irrigated and rainfed environments. There was no interaction between row pattern and N placement nor did row pattern affect corn productivity or N use efficiency parameters. In 2020, when less than 30 mm of rainfall occurred from the first N application through 2 weeks after the last N application, corn grain yield and agronomic N efficiency were not different among placement methods and averaged 11.1 Mg ha⁻¹ and 20.3 kg grain kg⁻¹ fertilizer N, respectively. However, in 2021, applying N with one knife increased corn grain yield by 7% to 14% compared to the two knives and surface dribble application methods; in that year, 235 mm of rainfall occurred from the first N application through 2 weeks after the last N application. Applying N with one knife appears to consistently improve crop productivity and N use efficiency parameters for both irrigated and rainfed environments.

Soil organic matter (SOM) and texture are key properties influencing soil nutrient and water dynamics but are time-consuming procedures for analytical laboratories. Our objective was to evaluate SOM and soil texture predictions using Mehlich-3 nutrients and pH in Arkansas soils. Particle size was determined by the hydrometer method (2- and 8-h readings) and SOM by loss on ignition. Two datasets were used to calibrate clay and sand (n = 409) and SOM (n = 1019) prediction models using simple and multiple regression. Estimated cation exchange capacity was highly correlated with clay, resulting in significant prediction models alone or combined with phosphorus (P); pH and copper (Cu); or pH, sodium (Na), and Cu (R² = 0.84, 0.88, 0.89, and 0.90; p < 0.0001, respectively). Soil nutrients were weakly correlated with sand, resulting in a prediction model with moderate accuracy when using Mehlich-3 P, calcium (Ca), Na, iron (Fe), and manganese (Mn) (R² = 0.49; p < 0.0001). Clay and sand prediction models presented comparable accuracy when validated on a new dataset (n = 103). Predicted sand and clay showed good accuracy in grouping soils into medium (65%) and fine (96%) textural categories but had limited ability to define the coarse-textural group (9%). SOM had moderate goodness-of-fit statistics for calibration and validation datasets using pH, P, Ca, Na, Mn, and zinc (R² = 0.65 and 0.70, respectively; p < 0.0001). Mehlich-3 nutrients can be used to estimate soil texture and assist with crop management decisions, but further research is needed to improve SOM prediction.