Effects of rice (Oryza sativaL.) cultivation and soil type on potassium mobilization and transformation behavior

Abstract

To understand the chemical behavior of potassium (K) in soil, rhizobox experiments were conducted to study the effects of K uptake by cultivated rice and soil type on K migration and transformation in soils. The aim of this study was to guide reasonable application of K fertilizer in different soil types. The results showed that at the maximum tillering stage, the migration distances of water-soluble K (Sol-K) were 6 and 5 cm, the depletion of exchangeable K (Ex-K) was 7 and 4 cm, and depletion of nonexchangeable K (Nonex-K) was 1 and 5 cm, respectively, in yellow cinnamon soil (YCS) and fluvo-aquic soil (FS). With the growth of rice, the migration distances of Sol-K showed little difference between YCS and FS. Throughout the season, the contributions of Sol-K, Ex-K, and Nonex-K to K uptake in YCS were 12.0%, 40.0%, and 48.0%, respectively, whereas their contributions in FS were 25.7%, 25.8%, and 48.5%, respectively. K uptake by rice was linearly related to the concentration of different forms of K in soils (R2 = 0.687*). In conclusion, soil type significantly affected K mobilization and transformation behavior. This indicated that the location of K fertilizer addition in the root zone should differ with soil type.