Agricultural & Environmental Letters最新文献

The safener fenclorim, effective in protecting rice (Oryza sativa L.) from the phytotoxicity of some herbicides, is regarded as a contaminant of emerging concern that may cause toxicological issues to ecosystems and humans who may consume the final harvested rice. This study investigated time-dependent environmental releases of fenclorim from rice seeds treated with the safener and insecticide with five different treatments. The treatment with fenclorim alone caused the greatest fenclorim releases from the seed, and the release magnitude was similar to the treatment that had fenclorim and insecticide in mixture. The fenclorim release was the least when treated with safener and insecticide in sequence. Based on the previous literatures, all fenclorim release magnitudes observed in this study were at toxicologically safe levels for various living organisms in the soil, and fenclorim residues determined in the final rice harvest were also safe levels below the instrumentally detectable level.

Core Ideas

Phosphorus (P) is an essential nutrient applied as fertilizer in agricultural fields. However, excessive fertilization leads to P build up in soils, increasing its potential to cause environmental pollution. The objective of this study was to evaluate the average P drawdown rate of 56 sites with drawdown management presented in 14 publications. Soil test P (STP) results were converted to Mehlich-3 equivalent and resampling analysis was used to compare the annual drawdown rate in fields grouped by four initial STP classes. The STP was reduced by 4.3%–8.2% per year, depending on the initial STP class. It took from 8.4 to 15.9 years to reduce the STP by half. The resulting equations from this meta-analysis can be used by landowners to estimate the time needed for STP drawdown by cropping without additional P to achieve the desired STP concentration.

Core Ideas

Achieving high corn yields while reducing fertilizer losses seems attainable through nitrogen (N) management decisions that include the use of cover crops (CCs). To determine whether CCs result in a net positive balance between N fertilization and crop utilization, we used US field trial data comparing corn systems with and without CCs, and estimated the amount of N fertilizer that CCs would replace and lead to equivalent grain yields under both systems. Overall, applying lower nitrogen rates to corn without cover crops resulted in similar or higher yields when legumes were used as cover crops (indicating positive nitrogen replacement in the amount of 62 kg ha⁻¹), but lower yields when grasses were used as cover crops (indicating negative nitrogen replacement in the amount of 24 kg ha⁻¹). Our results illustrate the benefits and trade-offs of integrating single CC species into a corn system, that is, reducing N inputs with legume CCs or supplementing N fertilizer to avoid possible grain yield penalties in the case of grass CCs. Quantifying the N replacement value of CCs would facilitate field-level recommendations and policy regulations aimed at promoting sustainable corn production in the United States.

Core Ideas

The invasive land snail Bulimulus bonariensis has become a significant pest in the Southern United States. This pest poses a threat to various crops, including cotton, citrus, and peanut, leading to potential yield losses, irrigation issues, and food contamination. This study investigated the effects of tillage and calcium fertilization on snail populations in peanut. The experiment was conducted in a randomized complete block design with four plot replications using the peanut cultivar Georgia 12Y. Treatments combined tillage methods with dolomitic lime or gypsum fertilization. The results showed that conventional tillage with the addition of dolomitic lime significantly reduced the number of snails compared to tillage plus gypsum, no-tillage plus dolomitic lime, and no-tillage plus gypsum. A slight increase in yield was noted in plots with tillage and gypsum application. These findings highlight the potential of tillage, especially when combined with dolomitic lime, as an effective strategy for managing B. bonariensis in peanut.

Core Ideas

In recent decades, vignerons have focused more on the world's mainstream varieties than on differentiating their varietal mix. This has led countries to become more similar to each other in their mix of winegrape varieties and more varietally concentrated. What are the drivers of those changes? In this study, we focus on one of those drivers, that is, climate similarities. We estimate statistical models to quantify the potential influence of 16 climate variables on varietal similarities across countries, as well as on how their varietal mixes have become more or less similar since 2000. The results indicate not only that countries with more similar climates have more similar varietal mixes but also that in recent years countries with more similar climates have become even more similar in their mixes. This, however, does not necessarily mean that vignerons have been planting the varieties that are better adapted to their climates.

Core Ideas