Potassium Bioavailability in a Tropical Kaolinitic Soil

Agronomy

Michael L. Thompson¹  Marcelo Raphael Volf²  Carlos Alexandre Costa Crusciol³  Ciro Antonio Rosolem³  Antônio Carlos de Azevedo⁴  John L. Kovar⁵ 

[1] Agronomy Department, Iowa State University, Ames, IA 50011, USA;Department Crop Science, São Paulo Western University, Raposo Tavares HWY, Km 572, Presidente Prudente 19067-175, Brazil;Department of Crop Science, College of Agricultural Sciences, São Paulo State University (UNESP), Botucatu 18610-034, Brazil;Department of Soil Science, University of São Paulo-C.P., Piracicaba 13418-900, Brazil;National Laboratory for Agriculture and the Environment, USDA Agricultural Research Service, 1015 North University Boulevard, Ames, IA 50011, USA;

关键词: potassium balance;    K in tropical soil;    plant K availability;    potassium cycle;    exchangeable K;    non-exchangeable K;   

DOI  :  10.3390/agronomy11102016

来源: DOAJ

【 摘 要 】

Some plant species are able to acquire non-exchangeable forms of K, which improve K availability and cycling in cropping systems, and which may explain the lack of response to K. However, this would not be expected in soils dominated by kaolinite. The aim of this study was to assess non-exchangeable K (Kne) use by three selected plant species grown in a tropical Haplic Plinthosol with low exchangeable K (Ke). A greenhouse experiment was conducted with soybean (Glycine max L., Merr.), maize (Zea mays L.), and ruzigrass (Urochloa ruziziensis) with or without K fertilization for three growing cycles. The crop treatments were compared with a control without plants. In the absence of K fertilization, all the tested plants were able to use non-exchangeable K and non-exchangeable K contributed more than 80% of the K demand of the plants in the first growing cycle, even in this kaolinitic soil. In the first growing cycle, soybean and maize took up more non-exchangeable K than ruzigrass, concomitant with higher dry matter yields. Over the three crop cycles, as both biomass yield and K uptake decreased in the unfertilized systems, the dependence of plants on non-exchangeable K decreased. Unfertilized ruzigrass showed a strong ability to acquire non-exchangeable K from the soil. Over the course of three growing cycles, K application decreased the absolute uptake of non-exchangeable K as well as its fractional contribution to total K uptake by the crops.

【 授权许可】

Unknown