Based on soil sample data in years, it is concluded that organic matter, total N, available P and rapidly available K increased compared with National Second Soil Survey. Furthermore, contents and changes of soil nutr...Based on soil sample data in years, it is concluded that organic matter, total N, available P and rapidly available K increased compared with National Second Soil Survey. Furthermore, contents and changes of soil nutrients were analyzed, and countermeasures for improving soil quality were proposed in order to protect and improve land comprehensive productivity and promote land resource sustainable use and agricultural sustainable development.展开更多
Simultaneous multi-element extraction has been increasing worldwide to improve soil laboratory testing quality and efficiency. This study sought to investigate the applicability of the Mehlich-1, Mehlich-3, and resin ...Simultaneous multi-element extraction has been increasing worldwide to improve soil laboratory testing quality and efficiency. This study sought to investigate the applicability of the Mehlich-1, Mehlich-3, and resin methods for simultaneous extraction of soil available P, K, Ca, and Mg as well as the effect of using conversion equations on nutrient recommendations for crops. Topsoil （0-20 cm） samples were taken from the most representative soil types used for crop production in southern Brazil with a wide range of chemical, physical, and mineralogical properties. Soil P, K, Ca, and Mg were simultaneously extracted using 1.0 mol L-1 KCl, Mehlich-1 and Mehlich-3 solutions, and membrane resin. The amounts of P extracted with the Mehlich-1 method were, on average, 50% lower than those extracted with the resin and Mehlich-3 methods. However, the resin method extracted the lowest amounts of K, Ca, and Mg. The use of conversion equations was suitable and it did not affect negatively the K recommendations for crops grown on soils of southern Brazil.展开更多
文摘Based on soil sample data in years, it is concluded that organic matter, total N, available P and rapidly available K increased compared with National Second Soil Survey. Furthermore, contents and changes of soil nutrients were analyzed, and countermeasures for improving soil quality were proposed in order to protect and improve land comprehensive productivity and promote land resource sustainable use and agricultural sustainable development.
基金Supported by the Soil Testing Laboratory at Federal University of Rio Grande do Sul (LAS-UFRGS), Brazil
文摘Simultaneous multi-element extraction has been increasing worldwide to improve soil laboratory testing quality and efficiency. This study sought to investigate the applicability of the Mehlich-1, Mehlich-3, and resin methods for simultaneous extraction of soil available P, K, Ca, and Mg as well as the effect of using conversion equations on nutrient recommendations for crops. Topsoil （0-20 cm） samples were taken from the most representative soil types used for crop production in southern Brazil with a wide range of chemical, physical, and mineralogical properties. Soil P, K, Ca, and Mg were simultaneously extracted using 1.0 mol L-1 KCl, Mehlich-1 and Mehlich-3 solutions, and membrane resin. The amounts of P extracted with the Mehlich-1 method were, on average, 50% lower than those extracted with the resin and Mehlich-3 methods. However, the resin method extracted the lowest amounts of K, Ca, and Mg. The use of conversion equations was suitable and it did not affect negatively the K recommendations for crops grown on soils of southern Brazil.
