Agricultural & Environmental Letters最新文献

Glanded (Gd) cottonseed (Gossypium hirsutum L.) contains scattered gossypol glands. Glandless (Gl) cottonseed is a new type of seed containing only trace levels of gossypol. This work quantitatively compared the content and migration pattern of Gd and Gl protein isolates. Both protein samples were subjected to sodium dodecyl sulfate (SDS)-gel electrophoresis, and the protein gel bands were separated into seven partitions for peptide mass spectroscopic analysis. While multiple peptide fragments (isoformers) of vicilin and legumin proteins were present in both samples, the percentage of vicilins in total seed protein was higher in Gd (74.9%) than in Gl (63.4%). In contrast, legumin proteins were more abundant in Gl (30.4%) than Gd (23.6%). Minor protein components such as lipid-related oleosins and vicilin-like antimicrobial peptides 2-2 were also observed at a relatively higher incidence in Gl compared with Gd, potentially reflecting a need for increased protein-related defense capability in the absence of gossypol against natural predators or adverse growth environment.

This study determined the effect of hybrid breeding on cultivar diversity in rice (Oryza sativa L.) production in China. The results showed that hybrid breeding led to increases in the Shannon index of cultivar diversity by 29–184% during the period 2011–2015 compared with the period 1986–1990 for 10 major hybrid rice-producing provinces in China. There was a significant exponential relationship between the Shannon index of cultivar diversity and the number of hybrid cultivars and the total number of cultivars across the 10 provinces and the two 5-yr periods. The results of this study also demonstrate that hybrid rice breeding resulted in a cultivar diversity that came close to saturation in some provinces, such as Anhui, Hunan, Jiangxi, and Sichuan, and highlight the urgent need for a reconsideration of the development of hybrid rice industrialization in China to avoid wasting resources caused by overbreeding.

Cover crops (CCs) were used on only ∼5% of harvested cropland in the United States in 2017. Lack of information about effective CC management and the costs and benefits of CCs may contribute to low adoption. We use CC management data from 112 farms in the Soil Health Partnership network (2015–2021) to characterize CC management practices and costs. Soil Health Partnership farmers spent a median of US$98.84 per hectare to plant CCs on trial fields in the 2021 crop year, and costs varied with management practices. Farmers also experimented with CC management practices; more than half of 100 farmers providing panel data used more than one seeding method, and the share “planting green” increased over time. This diversity of CC management practices, heterogeneity in costs (and benefits), and experimentation process—among other factors—may make it challenging for farmers to develop expectations about whether CCs will be profitable on their farm in the short, medium, or long-run.

The diffusive gradients in thin-films (DGT) technique shows in many publications a superior correlation to the amount of plant-available phosphorus (P) in soil. However, this technique cannot give information on the plant-available P species in soil. Therefore, we combined DGT with solution ³¹P nuclear magnetic resonance (NMR) spectroscopy. This was achieved by using a modified DGT device in which the diffusive layer had a larger pore size, the binding layer incorporated an adsorption material with a higher capacity, and the device had a larger exposure area. The spectroscopic investigation was undertaken after elution of the deployed DGT binding layer in a NaOH solution. Adsorption tests using solutions of known organic P compounds showed that a sufficient amount of these compounds could be adsorbed on the binding layer in order for them to be analyzed by solution ³¹P NMR spectroscopy. Furthermore, various intermediates of the hydrolysis of trimetaphosphate in soil could be also analyzed over time.

Core Ideas

Accelerated eutrophication due to human activity has been linked to an increase in the occurrence of cyanobacteria in freshwater systems. The purpose of this study was to document the occurrence of microcystin, a common cyanotoxin, within northwest Arkansas streams. Twenty streams were sampled from May through October 2018, and water and periphyton samples were analyzed for microcystin and chlorophyll-a (CHL-a). Mean microcystin concentrations in water samples were low across sites, ranging from < 0.10 to 0.21 μg L⁻¹. Mean microcystin in the periphyton across sites ranged from 2.6 to 9.9 μg m⁻² and were within values observed in the literature. All microcystin concentrations measured in these Ozark streams were well below the current USEPA recreational guidelines of 8.0 μg L⁻¹ and the drinking water guidelines of 0.3 μg L⁻¹ for infants and 1.6 μg L⁻¹ for adults.

Nutrient stratification of no-till managed soil can affect soil test analysis levels of plant-available phosphorus (P). Research has suggested sampling to different depths due to soil acidity, but little work has been conducted to investigate any change to sampling recommendations for immobile nutrients. The objective of this study was to determine the soil sampling depth that had the greatest relationship with yield response to fertilizer-P. The depths sampled in this study were 0–5, 0–10, 0–15, 10–30, 5–10, 5–15, 10–15, and 15–30 cm. The results indicated that the top 15 cm of a soil profile had the greatest amount of Mehlich 3 extractable P (M3P) available and that the 5-to-10 and 5-to-15-cm depths had the highest correlation with relative yield. Soil depths outside of the proposed root zone of winter wheat (Triticum aestivum L.) (15–30 cm) had the lowest correlation with yield response.

The U.S. grain-finished beef system is highly productive but has many negative consequences for human health and well-being because it pollutes surface and groundwaters, exacerbates flooding, reduces biodiversity, and contributes to climate change. Moving the entire U.S. grain-fed beef production system to a grass-finished system is possible without displacing food production and under conservative soil carbon (C) change estimates would result in a reduced but similar C footprint, while improving soil health, water quality, and biodiversity. More optimistic estimates for soil C accumulation indicate the system would result in significant atmospheric C drawdown. Agroecological transformation like this is limited only by our imagination and policies that incentivize agriculture for the public good rather than profits for a few.

The severe manipulation of soil that occurs in the right-of-way (ROW) easement areas for pipeline installation leads to soil degradation and yield loss. The objectives of this study were to investigate the use of the Visual Evaluation of Soil Structure method (VESS) and root litter sampling as alternative ways to characterize pipeline installation impacts on soil degradation. Digital images of aggregate specimens and root samples were obtained from disturbed (trenched and highly trafficked ROW areas) and undisturbed (adjacent to the ROW) soil profiles one month after maize (Zea mays L.) harvest in Iowa. Images of soil aggregates indicated that pipeline installation deteriorated soil structure. Root attributes were significantly (p < 0.05) affected by the ROW activities. The non-decomposed root mass in the highly trafficked area (3,568 kg ha^–1) was two times greater than the root mass in undisturbed soil (1,779 kg ha^–1). These data provide evidence that soil structure quality and root decomposition rates are affected by soil disturbance. The VESS and root measurements can be used in future studies to evaluate the impacts of soil disturbance.