Land Degradation & Development最新文献

Effective evaluation of cultivated land quality is crucial for sustainable agricultural management. Existing research often focuses on regional scales and lacks sufficient detailed analysis of spatial distribution and limiting factors at localized scales. This study aims to select the key indicators to evaluate cultivated land quality and analyze their influence on cultivated land quality at the county level. Taking Changtu County as the research area, principal component analysis (PCA) was employed to identify the most effective Minimum Data Set (MDS) for evaluation, including cultivated layer thickness, soil organic matter (SOM), pH, bulk density (BD), and cultivated layer texture. Additionally, an obstacle degree model was used to analyze restricting factors and their degrees of impact. Results showed that the constructed MDS could replace all indicators for cultivated land quality evaluation. Quality was higher in central areas and lower in eastern and western regions. SOM content decreases with the decrease of quality grade, significantly affecting the quality distribution, and pH in the medium category (Grades III and VI) cultivated lands were lower compared to other categories. Low organic matter content and low pH levels were the main obstacles affecting cultivated land quality, with average obstacle degrees of 43.5% and 29.3%, respectively. Low SOM content significantly affected land quality, particularly in the western region, whereas acidic soils in the eastern region influenced quality grade distribution. Thus, strategies for pH control and SOM enhancement are essential for improving cultivated land quality. This study provides valuable insights into sustainable agriculture.

Obstacles related to the continuous cropping of sweet potatoes (Ipomoea batatas (L.) Lam.) restrict its intensive production. However, the effects of continuous cropping on soil properties and/or the rhizosphere microbial community are largely unclear. In this study, we analyzed changes in rhizosphere soil chemical properties and microbial communities of sweet potatoes across different cultivation years. We observed that the microbial diversity and complexity of the fungal ecological network in rhizosphere soils of sweet potatoes were decreased after 5 years of continuous cropping, with significant enrichment in Sphingobium, Gemmatimonas, Volutella, and Neoidriella. Tuber yield, soil pH, and available potassium (AK) content were significantly reduced after continuous cropping, with the soil microbial community having the highest correlation with pH, AK, and ammonium nitrogen (NH₄ ⁺-N). Specifically, soil pH and AK were positively correlated with Bacillus and Gaiella, and negatively correlated with some plant-pathogenic fungi (Volutella and Neoidriella), while NH₄ ⁺-N showed the opposite trend. In addition, soil pH, AK, and the relative abundance of Bacillus were positively correlated with tuber yield, while Volutella showed the opposite trend. In summary, the continuous cropping of sweet potatoes negatively affects rhizosphere soil health, resulting in imbalanced soil fertility and an increased abundance of pathogens. These results improve our understanding of factors driving obstacles faced with the continuous cropping of sweet potatoes, enabling future studies and the development of technologies to overcome these obstacles.