Aldicarb and aldoxycarb pesticides were applied to potato fields in central Wisconsin to study the degradation and movement of their carbamate residues within the soil profile. Aldicarb and aldoxycarb residues degraded at similar rates with half-lives ranging from 0.9 to 1.4 months. Although unsaturated-zone residue measurements indicated relatively minor differences among the three plots, residues were detected in shallow groundwater beneath plots treated with aldicarb or aldoxycarb at planting. Residues beneath the plot treated with aldicarb at emergence were much lower and the timing of these residues suggests they might have resulted from migration of residues from the plot treated with aldicarb at planting. This study confirms the results of previous and concurrent research programs which suggest that emergence applications of aldicarb reduce the potential for residues to enter shallow groundwater without reducing insect control or potato yields. 相似文献
Environmental Science and Pollution Research - Magnetic nanostructured MnFe2O4 with different morphologies, synthesized via chemical co-precipitation and hydrothermal method, was assayed as... 相似文献
The rhizosphere microbiome plays critical roles in plant growth and is an important interface for resource exchange between plants and the soil environment. Crops at various growing stages, especially the seedling stage, have strong shaping effects on the rhizosphere microbial community, and such community reconstruction will positively feed back to the plant growth. In the present study, we analyzed the variations of bacterial and fungal communities in the rhizosphere of four crop species: rice, soybean, maize, and wheat during successive cultivations (three repeats for the seedling stages) using 16S rRNA gene and internal transcribed spacer (ITS) high-throughput sequencing. We found that the relative abundances of specific microorganisms decreased after different cultivation times, e.g., Sphingomonas, Pseudomonas, Rhodanobacter, and Caulobacter, which have been reported as plant-growth beneficial bacteria. The relative abundances of potential plant pathogenic fungi Myrothecium and Ascochyta increased with the successive cultivation times. The co-occurrence network analysis showed that the bacterial and fungal communities under maize were much more stable than those under rice, soybean, and wheat. The present study explored the characteristics of bacteria and fungi in crop seedling rhizosphere and indicated that the characteristics of indigenous soil flora might determine the plant growth status. Further study will focus on the use of the critical microorganisms to control the growth and yield of specific crops.
