Effects of acid modified biochar on potassium uptake, leaching and balance in an alternate wetting and drying paddy ecosystem

Hongwei Han; Taotao Chen; Chang Liu; Feng Zhang; Yidi Sun; Yikui Bai; Jun Meng; Daocai Chi; Wenfu Chen

doi:10.1016/j.scitotenv.2023.166344

Effects of acid modified biochar on potassium uptake, leaching and balance in an alternate wetting and drying paddy ecosystem

Sci Total Environ. 2023 Nov 20:900:166344. doi: 10.1016/j.scitotenv.2023.166344. Epub 2023 Aug 18.

Authors

Hongwei Han¹, Taotao Chen², Chang Liu¹, Feng Zhang¹, Yidi Sun³, Yikui Bai¹, Jun Meng⁴, Daocai Chi¹, Wenfu Chen⁵

Affiliations

¹ College of Water Conservancy, Shenyang Agricultural University, Shenyang 110866, China.
² College of Water Conservancy, Shenyang Agricultural University, Shenyang 110866, China; National Biochar Institute, Shenyang Agricultural University, Shenyang 110866, China; Key Laboratory of Biochar and Soil Improvement, Ministry of Agriculture and Rural Affairs, Shenyang 110866, China. Electronic address: taotao-chen@syau.edu.cn.
³ College of Hydraulic Science and Engineering, Yangzhou University, Yangzhou, Jiangsu 225009, China.
⁴ National Biochar Institute, Shenyang Agricultural University, Shenyang 110866, China; Key Laboratory of Biochar and Soil Improvement, Ministry of Agriculture and Rural Affairs, Shenyang 110866, China. Electronic address: mengjun1217@syau.edu.cn.
⁵ National Biochar Institute, Shenyang Agricultural University, Shenyang 110866, China; Key Laboratory of Biochar and Soil Improvement, Ministry of Agriculture and Rural Affairs, Shenyang 110866, China.

PMID: 37597543
DOI: 10.1016/j.scitotenv.2023.166344

Abstract

Straw biochar amended soils reduce fertilizer losses and alleviate soil K-exhaustion, while decrease grain yield due to its high pH. H₂SO₄-modified biochar has been studied as a means to enhance the advantages of biochar and address yield decrease. However, little information is available on its effects on aboveground K uptake, soil K fixation, K leaching, and utilization in paddy rice systems, especially under water stress. A 3-year field experiment was conducted with two irrigation regimes (continuously flooded irrigation, I_CF and alternate wetting and drying irrigation, I_AWD) as main plots and 0 (control), 20 t ha^-1 biochar (B₂₀), and 20 t ha^-1 acid-modified biochar (B_20A-M) as subplots. The results showed that I_AWD significantly decreased water percolation by 9.26 %-14.74 % but increased K leaching by 10.84 %-15.66 %. Compared to B₀, B₂₀ and B_20A-M significantly increased K leaching by 32.40 % and 30.42 % in 2019, while decreased it by 11.60 %-14.01 % in 2020 and 2021. Both B₂₀ and B_20A-M significantly improved aboveground K uptake by 3.45 %-6.71 % throughout the three years. B₂₀ reduced grain yield in 2019 and increased it in 2020 and 2021, while B_20A-M increased grain yield throughout the three years. Apparent K balance (AKB) from pre-transplanting to post-harvest over the three years suggested that I_AWD significantly increased the risk of soil K depletion but B₂₀ and B_20A-M significantly increased AKB, thereby addressing the depletion of it. I_AWDB_20A-M have a comparable AKB with I_CFB_20A-M, but had up to 18.3 % and 21.61 % higher AKB than I_AWDB₂₀ and I_CFB₂₀. Therefore, the use of H₂SO₄ modified biochar could produce higher grain yield with lower K leaching for addition in I_AWD paddy systems, which is beneficial to mitigate soil K depletion and ensure a sustainable agricultural production.

Keywords: Acid-modified biochar; Apparent potassium balance; Paddy field; Potassium leaching; Potassium uptake.

MeSH terms

Biological Transport
Ecosystem*
Edible Grain*
Potassium
Soil

Substances

biochar
Soil
Potassium