Improving soil quality while achieving higher productivity is the major challenge in the agricultural industry. Wheat(Triticum aestivum L.)–maize(Zea mays L.)(W–M) rotation is the dominant planting pattern in the Hu...Improving soil quality while achieving higher productivity is the major challenge in the agricultural industry. Wheat(Triticum aestivum L.)–maize(Zea mays L.)(W–M) rotation is the dominant planting pattern in the Huang-HuaiHai Plain and is important for food security in China. However, the soil quality is deteriorating due to the W–M rotation’s long-term, intensive, and continuous cultivation. Introducing legumes into the W–M rotation system may be an effective way to improve soil quality. In this study, we aimed to verify this hypothesis by exploring efficient planting systems(wheat–peanut(Arachis hypogaea L.)(W–P) rotation and wheat rotated with maize and peanut intercropping(W–M/P)) to achieve higher agricultural production in the Huang-Huai-Hai Plain. Using traditional W–M rotation as the control, we evaluated crop productivity, net returns, soil microorganisms(SMs), and soil organic carbon(SOC) fractions for three consecutive years. The results indicated that wheat yields were significantly increased under W–P and W–M/P(382.5–579.0 and 179.8–513.1 kg ha-1, respectively) compared with W–M. W–P and W–M/P provided significantly higher net returns(58.2 and 70.4%, respectively) than W–M. W–M/P and W–M retained the SOC stock more efficiently than W–P, increasing by 25.46–31.03 and 14.47–27.64%, respectively, in the 0–20 cm soil layer. Compared with W–M, W–M/P improved labile carbon fractions;the sensitivity index of potentially mineralizable carbon, microbial biomass carbon(MBC), and dissolved organic carbon was 31.5, 96.5–157.2, and 17.8% in 20–40, 10–40, and 10–20 cm soil layers, respectively. The bacterial community composition and bacteria function were altered as per the soil depth and planting pattern. W–M/P and W–M exhibited similar bacterial community composition and function in 0–20 and 20–40 cm soil layers. Compared with W–P, a higher abundance of functional genes, namely, contains mobile elements and stress-tolerant, and a lower abundan展开更多
A partition of unity level set method with moving knot Compactly Supported Radial Basis Functions(CS-RBFs)is proposed for optimizing variable stiffness composite structures.The iso-contours of a level set function are...A partition of unity level set method with moving knot Compactly Supported Radial Basis Functions(CS-RBFs)is proposed for optimizing variable stiffness composite structures.The iso-contours of a level set function are utilized to represent the curved fiber paths,and the tan-gent vector of the iso-contour defines the orientation of fiber.The level set function of the full design domain is constructed according to the Partition of Unity(POU)method by a set of local level set functions defined on an array of overlapping subdomains,and they are constructed by using the CS-RBFs.The positions of knots are iteratively changed during the optimization to improve the performance of composite structures.Several examples of compliance minimization are presented.展开更多
基金National Natural Science Foundation of China (42107376)the earmarked fund for China Agriculture Research System (CARS-13)。
文摘Improving soil quality while achieving higher productivity is the major challenge in the agricultural industry. Wheat(Triticum aestivum L.)–maize(Zea mays L.)(W–M) rotation is the dominant planting pattern in the Huang-HuaiHai Plain and is important for food security in China. However, the soil quality is deteriorating due to the W–M rotation’s long-term, intensive, and continuous cultivation. Introducing legumes into the W–M rotation system may be an effective way to improve soil quality. In this study, we aimed to verify this hypothesis by exploring efficient planting systems(wheat–peanut(Arachis hypogaea L.)(W–P) rotation and wheat rotated with maize and peanut intercropping(W–M/P)) to achieve higher agricultural production in the Huang-Huai-Hai Plain. Using traditional W–M rotation as the control, we evaluated crop productivity, net returns, soil microorganisms(SMs), and soil organic carbon(SOC) fractions for three consecutive years. The results indicated that wheat yields were significantly increased under W–P and W–M/P(382.5–579.0 and 179.8–513.1 kg ha-1, respectively) compared with W–M. W–P and W–M/P provided significantly higher net returns(58.2 and 70.4%, respectively) than W–M. W–M/P and W–M retained the SOC stock more efficiently than W–P, increasing by 25.46–31.03 and 14.47–27.64%, respectively, in the 0–20 cm soil layer. Compared with W–M, W–M/P improved labile carbon fractions;the sensitivity index of potentially mineralizable carbon, microbial biomass carbon(MBC), and dissolved organic carbon was 31.5, 96.5–157.2, and 17.8% in 20–40, 10–40, and 10–20 cm soil layers, respectively. The bacterial community composition and bacteria function were altered as per the soil depth and planting pattern. W–M/P and W–M exhibited similar bacterial community composition and function in 0–20 and 20–40 cm soil layers. Compared with W–P, a higher abundance of functional genes, namely, contains mobile elements and stress-tolerant, and a lower abundan
基金supported by the National Natural Science Foundation of China(No.51975227).
文摘A partition of unity level set method with moving knot Compactly Supported Radial Basis Functions(CS-RBFs)is proposed for optimizing variable stiffness composite structures.The iso-contours of a level set function are utilized to represent the curved fiber paths,and the tan-gent vector of the iso-contour defines the orientation of fiber.The level set function of the full design domain is constructed according to the Partition of Unity(POU)method by a set of local level set functions defined on an array of overlapping subdomains,and they are constructed by using the CS-RBFs.The positions of knots are iteratively changed during the optimization to improve the performance of composite structures.Several examples of compliance minimization are presented.
