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Sloping farmland is prevalent in hilly red soil areas of South China. Improper tillage patterns induce decreased soil organic matter, soil aggregate breakdown, and nutrient imbalance, thereby restricting crop production. However, the stoichiometric characteristics could reflect the nutrient availability which was mostly studied on bulk soil. The stoichiometric characteristics of soil aggregates with multiple functions in farmlands has rarely been studied. The study was to reveal the impact of tillage patterns on the size distribution, nutrient levels, and stoichiometric ratios of soil aggregates after 20 years’ cultivation. Soil samples of 0–20 cm and 20–40 cm from five tillage patterns, bare-land control (BL), longitudinal-ridge tillage (LR), conventional tillage + straw mulching (CS), cross-ridge tillage (CR), and longitudinal-ridge tillage + hedgerows (LH) were collected. The elemental content (C, N and P) and soil aggregate size distribution were determined, and the stoichiometric ratios were subsequently calculated. Through our analysis and study, it was found that the nutrient content of >2 mm soil aggregates in all plots was the highest. In the hedgerow plots, >2 mm water-stable soil aggregate content was increased. Therefore, LH plots have the highest content of organic matter and nutrients. After 20 years of cultivation, stoichiometric ratio of each plot showed different changes on soil aggregates at different levels. the C:N, C:P, and N:P ratios are lower than the national average of cultivated land. Among of them, the stoichiometric ratio in the LH plot is closer to the mean and showed better water-stable aggregate enhancement. Therefore, longitudinal-ridge tillage + hedgerows can be recommended as a cultivation measure. This study provides a reference for determining appropriate tillage measures, balancing nutrient ratios, and implementing rational fertilization.
Jie Zhang; Yaojun Liu; Taihui Zheng; Xiaomin Zhao; Hongguang Liu; Yongfen Zhang. Nutrient and Stoichiometric Characteristics of Aggregates in a Sloping Farmland Area under Different Tillage Practices. Sustainability 2021, 13, 890 .
AMA StyleJie Zhang, Yaojun Liu, Taihui Zheng, Xiaomin Zhao, Hongguang Liu, Yongfen Zhang. Nutrient and Stoichiometric Characteristics of Aggregates in a Sloping Farmland Area under Different Tillage Practices. Sustainability. 2021; 13 (2):890.
Chicago/Turabian StyleJie Zhang; Yaojun Liu; Taihui Zheng; Xiaomin Zhao; Hongguang Liu; Yongfen Zhang. 2021. "Nutrient and Stoichiometric Characteristics of Aggregates in a Sloping Farmland Area under Different Tillage Practices." Sustainability 13, no. 2: 890.
Quantitatively figuring out the effects of climate and land-use change on water resources and their components is essential for water resource management. This study investigates the effects of climate and land-use change on blue and green water and their components in the upper Ganjiang River basin from the 1980s to the 2010s by comparing the simulated changes in blue and green water resources by using a Soil and Water Assessment Tool (SWAT) model forced by five climate and land-use scenarios. The results suggest that the blue water flow (BWF) decreased by 86.03 mm year−1, while green water flow (GWF) and green water storage (GWS) increased by 8.61 mm year−1 and 12.51 mm year−1, respectively. The spatial distribution of blue and green water was impacted by climate, wind direction, topography, and elevation. Climate change was the main factor affecting blue and green water resources in the basin; land-use change had strong effects only locally. Precipitation changes significantly amplified the BWF changes. The proportion of surface runoff in BWF was positively correlated with precipitation changes; lateral flow showed the opposite tendency. Higher temperatures resulted in increased GWF and decreased BWF, both of which were most sensitive to temperature increases up to 1 °C. All agricultural land and forestland conversion scenarios resulted in decreased BWF and increased GWF in the watershed. GWS was less affected by climate and land-use change than GWF and BWF, and the trends in GWS were not significant. The study provides a reference for blue and green water resource management in humid areas.
Yongfen Zhang; Chongjun Tang; Aizhong Ye; Taihui Zheng; Xiaofei Nie; Anguo Tu; Hua Zhu; Shiqiang Zhang. Impacts of Climate and Land-Use Change on Blue and Green Water: A Case Study of the Upper Ganjiang River Basin, China. Water 2020, 12, 2661 .
AMA StyleYongfen Zhang, Chongjun Tang, Aizhong Ye, Taihui Zheng, Xiaofei Nie, Anguo Tu, Hua Zhu, Shiqiang Zhang. Impacts of Climate and Land-Use Change on Blue and Green Water: A Case Study of the Upper Ganjiang River Basin, China. Water. 2020; 12 (10):2661.
Chicago/Turabian StyleYongfen Zhang; Chongjun Tang; Aizhong Ye; Taihui Zheng; Xiaofei Nie; Anguo Tu; Hua Zhu; Shiqiang Zhang. 2020. "Impacts of Climate and Land-Use Change on Blue and Green Water: A Case Study of the Upper Ganjiang River Basin, China." Water 12, no. 10: 2661.
National large-scale soil and water conservation controls on the Gangjiang River basin have been documented, but the effect of governance on regional watershed hydrology and how the main driving factors act have not been systematically studied yet. To do this, this study evaluated changing trends and detected transition years for both streamflow and sediment discharge using long-term historical records at seven hydrological stations in the Ganjiang River basin over the past 50 years. The double mass curve (DMC) method was used to quantify the effects of both climate change and human activities on hydrological regime shifts. The results showed that the distributions of precipitation, streamflow, and sediment discharge within a year are extremely uneven and mainly concentrated in the flood season of Jiangxi Province. None of the stations showed significant trends over time for either annual precipitation or streamflow, while the annual sediment discharge at most stations decreased significantly over time. The estimation of sediment discharge via DMC indicated that after the transition years, there were rapid reductions in sediment discharge at all hydrological stations, and the average decline degree of midstream and downstream were much larger than that of upstream. Human activities, especially the increase of vegetation cover and construction of large and medium-sized reservoirs, provided a significantly greater contribution to the reduction of sediment discharge than did precipitation changes. As a case study of river evolution under global change environment, this study could provide scientific basis for the control of soil erosion and the management of water resources in Ganjiang River, as well as for the related research of Poyang Lake and the Yangtze River basin of China.
Li-Ping Guo; Xing-Min Mu; Jian-Min Hu; Peng Gao; Yong-Fen Zhang; Kai-Tao Liao; Hua Bai; Xiu-Long Chen; Yue-Jun Song; Ning Jin; Qiang Yu. Assessing Impacts of Climate Change and Human Activities on Streamflow and Sediment Discharge in the Ganjiang River Basin (1964–2013). Water 2019, 11, 1679 .
AMA StyleLi-Ping Guo, Xing-Min Mu, Jian-Min Hu, Peng Gao, Yong-Fen Zhang, Kai-Tao Liao, Hua Bai, Xiu-Long Chen, Yue-Jun Song, Ning Jin, Qiang Yu. Assessing Impacts of Climate Change and Human Activities on Streamflow and Sediment Discharge in the Ganjiang River Basin (1964–2013). Water. 2019; 11 (8):1679.
Chicago/Turabian StyleLi-Ping Guo; Xing-Min Mu; Jian-Min Hu; Peng Gao; Yong-Fen Zhang; Kai-Tao Liao; Hua Bai; Xiu-Long Chen; Yue-Jun Song; Ning Jin; Qiang Yu. 2019. "Assessing Impacts of Climate Change and Human Activities on Streamflow and Sediment Discharge in the Ganjiang River Basin (1964–2013)." Water 11, no. 8: 1679.