Effects of Rainfall Change on Agricultural Non-point Source Pollution in Liangping County

[Objective] The study aimed to discuss the impact of rainfall change on agricultural non-point source pollution in Uangping County. E Method ] Based on daily precipitation data of Liangping from 1955 to 2011, changes of precipitation and frequency of heavy rain in Uangping during a year were analyzed firstly, and then the risk of surface runoff caused by rainfall to agricultural non-point source pollution was studied, finally chan- ging trends of annual average precipitation and frequency during 1955 -2011 were discussed using Mann-Kendal method. [ Result] Total precipitati- on of heavy rain in Liangping mainly concentrated from late May to early September, especially in eady and middle July as well as early September. Meanwhile, fertilizer and pesticide were applied to main crops in Liangping in the periods above, so agricultural non-point source pollution became more serious. In recent 57 years, annual average precipitation and frequency of heavy rain in Liangping showed an increasing trend respectively, and surface runoff rose with the increase of the precipitation, thereby probably enlarging agricultural pollution area. [ Conclusion] The research could provide a theoretical basis and technical support for the control of agricultural non-point source pollution.

Study on Rice Water Requirement of Liangping County under Climate Change Background

Under global climate change background,using daily meteorological data at Liangping ground meteorological station during 1961- 2012,we calculated crop water requirement and net irrigation water requirement during rice growth period in Liangping County,and analyzed its climate tendency rate. Results showed that climate tendency rate of crop water requirement during growth period of rice was only- 0. 007 mm /10 a; climate tendency rate of rainfall was- 0. 06 mm /10 a,but interannual change was relatively larger; climate tendency rate of net irrigation water requirement was 0. 011 mm /10 a. In the years when drought occurred,such as 2006 and 2011,both rice water requirement and net irrigation water requirement in Liangping were greatly higher than means over the years. Therefore,we should focus on drought pre-warning and risk management improving drought disaster prevention in Liangping in the future.

Effects of Intracratonic Strike-slip Fault on the Differentiation of Carbonate Microfacies: A Case Study of a Permian Platform Margin in the Sichuan Basin(SW China)

In intracratnoic basins, the effect of strike-slip faults on sedimentary microfacies is generally underestimated due to their small scale. Based on the integration of core, well logs, and three-dimensional seismic data, this study presents a comprehensive analysis of the Permian carbonate platform and strike-slip faults in the southwestern Kaijiang-Liangping trough of the Sichuan Basin. The relationship between strike-slip faults and Permian carbonate microfacies is investigated. The results reveals the existence of a NW-trending strike-slip fault zone along the platform margin, exhibiting clear segmentation. The western side of the study area exhibits a rimmed platform margin characterized by type I reefs, which corresponds to the presence of a large-scale strike-slip fault zone. In contrast, the eastern side is characterized by a norimmed and weak rimmed platform margin, accompanied by type II reefs, which align with smaller strike-slip fault zones. It was found that the strike-slip fault had some effects on the platform and reef-shoal complex of the Permain Changxing Formation. First, the platform was divided by strike-slip fault into three segments to show rimmed, week rimmed and norimmed platform. Second, reef-shoal complex devolped along the faulted high position in the strike-slip fault zone, and separated by faulted depression. Third, strike-slip faults can offset or migrated the reef-shoal complex and platform margin. Additionally, the thickness of the platform margin varies across strike-slip fault zone, which is related to the activity of strike-slip faults. The strike-slip faults affect the microfacies by controlling the pre-depositional paleotopography. This case suggests that the strike-slip faults play a crucial role in the diversity and distribution of carbonate microfacies in the intracratonic basin.