Spatial variability of the nutrient balance and related NPSP risk analysis for agro-ecosystems in China in 2010

2014 ◽  
Vol 193 ◽  
pp. 42-52 ◽  
Author(s):  
Xuelei Wang ◽  
Aiping Feng ◽  
Qiao Wang ◽  
Chuanqing Wu ◽  
Zhong Liu ◽  
...  
Revista CERES ◽  
2011 ◽  
Vol 58 (2) ◽  
pp. 256-261 ◽  
Author(s):  
Samuel de Assis Silva ◽  
Julião Soares de Souza Lima ◽  
Daniel Marçal de Queiroz

The combined use of precision agriculture and the Diagnosis and Recommendation Integrated System (DRIS) allows the spatial monitoring of coffee nutrient balance to provide more balanced and cost-effective fertilizer recommendations. The objective of this work was to evaluate the spatial variability in the nutritional status of two coffee varieties using the Mean Nutritional Balance Index (NBIm) and its relationship with their respective yields. The experiment was conducted in eastern Minas Gerais in two areas, one planted with variety Catucaí and another with variety Catuaí. The NBIm of the two varieties and their yields were analyzed through geostatistics and, based on the models and parameters of the variograms, were interpolated to obtain their spatial distribution in the studied areas. Variety Catucai, with grater spatial variability, was more nutritional unbalanced than variety Catuai, and consequently produced lower yields. Excess of Fe and Mn makes these elements limiting yield factors.


2021 ◽  
Vol 9 ◽  
Author(s):  
Kai Dong ◽  
Zefa Li ◽  
Xiang Lu ◽  
Chen Chen ◽  
Jinbao Sheng ◽  
...  

Many of the existing reservoir dams are constructed in alpine and gorge regions, where the topography and geological conditions are complicated, bank slopes are steep, and landslides have a high potential to occur. Surges triggered by landslides in the reservoir are one of the major causes of dam overtopping failures. Many factors affect the slope stability of reservoir banks and the height of surges triggered by landslides, such as spatial variability of material properties, speed of landslides, etc. To reasonably evaluate dam overtopping risk caused by landslide-induced surges is a key technology in engineering that is urgent to be solved. Therefore, a novel risk analysis method for overtopping failures caused by waves triggered by landslides induced by bank instability considering the spatial variability of material parameters is proposed in this study. Based on the random field theory, the simulation method for the spatial variability of material parameters is proposed, and the most dangerous slip surface of the reservoir bank slope is determined with the minimum value of the safety factors. The proxy risk analysis models for both the slope instability and dam overtopping are constructed with the consideration of spatial variability of material parameters, and then the dam overtopping failure risk caused by landslide-induced surges is calculated using the Monte-Carlo sampling. The proposed models are applied to a practical engineering project. Results show that the spatial variability of material properties significantly affects the instability risk of slopes, without considering which the risks of slope instability and dam overtopping may be overestimated. This study gives a more reasonable and realistic risk assessment of dam overtopping failures, which can provide technical support for the safety evaluation and risk control of reservoir dams.


2020 ◽  
Vol 46 (12) ◽  
pp. 2295-2313
Author(s):  
Yoko Higuchi ◽  
Yoshiyuki Ueda ◽  
Kazuhisa Shibata ◽  
Jun Saiki

2010 ◽  
Vol 58 (S 01) ◽  
Author(s):  
J Schönebeck ◽  
B Reiter ◽  
O Haye ◽  
D Böhm ◽  
M Ismail ◽  
...  

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