Effects of soil texture and rates of K input on potassium balance in tropical soil. (September 2017)

• Record Type: Journal Article
• Authors: Rosolem, C. A.; Steiner, F.
• Is Part Of: European journal of soil science. Volume 68:Number 5(2017:Oct.)
• Page Start: 658
• Page End: 666
• Publication Date: 2017-09
• Subjects: Soil science -- Periodicals; 631.4
• DOI: 10.1111/ejss.12460
• Languages: English
• ISSNs: 1351-0754

Abstract

Abstract : The efficiency of potassium (K) fertilizer use is important in sustainable agriculture and is affected by losses related to soil texture. However, there is no information on how much K is lost by leaching in tropical soil. The effects of rates of fertilizer‐K application on K dynamics and budget in a soil–plant system at depths up to 1 m were studied in Botucatu, São Paulo, Brazil, from 2000 to 2012; soil types were a sandy clay loam (250 g clay kg −1 ) and a clay soil (670 g clay kg −1 ) under no‐till management. The soils were fertilized annually with 0, 25, 50, 75, 100, 125 and 150 kg K ha −1 . Annual applications of 50–75 kg K ha −1 to the sandy clay loam soil and 25–50 kg K ha −1 to the clay soil were sufficient to achieve a large grain yield and maintain soil exchangeable K in the soil profile. An annual application of up to 150 kg K ha −1 to clay soil does not result in a large amount of leaching below 1‐m depth. Non‐exchangeable K plays an important role in tropical cropping systems. The increase in rates of fertilizer‐K application intensifies losses by leaching below 1 m in sandy clay loam soil, which represents 16–52% of the K added as fertilizer. Therefore, because of the considerable leaching potential, splitting the applications of K is an important management strategy to minimize losses and improve the efficiency of K use in tropical soil with small clay contents. Highlights: We investigated the effect of soil texture on K movement in the profile. Losses of K were estimated in a cropping system with cover crops. In tropical soil clay content plays an important role in the movement of K in the soil profile. In clay soil K losses are small, but can be up to 52% of the nutrient applied to sandy soil.