Enzyme activities and organic matter mineralization in response to application of gypsum, manure and rice straw in saline and sodic soils

Saline and alkaline soils are a challenge for sustainable crop production. The use of organic and inorganic amendments is a common practice to increase the fertility of salt-affected soils that can trigger faster carbon (C) and nitrogen (N) cycling. We examined the effects of gypsum (Gyps), farm manure (Manure) and rice straw (Straw) on enzyme activities, organic matter mineralization and CO2 emissions in two salt-affected soils [Solonchak (saline); pH: 8, electrical conductivity (EC): 6.5, sodium adsorption ratio (SAR): 2.5, and Solonetz (alkaline sodic); pH: 8.9, EC: 1.6, SAR: 17]. Gypsum addition decreased soil pH up to 0.62 and 0.30 units, SAR 1.2 and 5.2 units, and EC 2.9 and 1.4 units in Solonchak and Solonetz, respectively. Dissolved organic C, microbial biomass C, dissolved organic N, mineral N (NO3− and NH4+), enzyme activities (urease, invertase, catalase, phosphatase, phenol-oxidase), alkali extractable phenols, and available phosphorous increased with the application of all amendments in both soils. Solonetz released more CO2 than Solonchak, whereas maximum CO2 emissions were common after manure application (3140 mg kg−1 in Solonchak, and 3890 mg kg−1 in Solonetz). We conclude that high SAR and low EC increase CO2 emissions through accelerated C and N cycling and manure decomposition in Solonetz soils. © 2023 Elsevier Inc.

Authors
Shaaban M. , Wu Y. , Núñez-Delgado A. , Kuzyakov Y. , Peng Q.-A. , Lin S. , Hu R.
Publisher
Academic Press Inc.
Language
English
Status
Published
Number
115393
Volume
224
Year
2023
Organizations
  • 1 Department of Soil Science, Bahauddin Zakariya University, Multan, Pakistan
  • 2 College of Resources and Environment, Huazhong Agricultural University, Wuhan, China
  • 3 Department of Soil Science and Agricultural Chemistry, Engineering Polytechnic School, Campus Lugo, University of Santiago de Compostela, Spain
  • 4 Department of Agricultural Soil Science, Department of Soil Science of Temperate Ecosystems, University of Göttingen, Göttingen, 37077, Germany
  • 5 Peoples Friendship University of Russia (RUDN University), Moscow, 117198, Russian Federation
  • 6 School of Environmental Engineering, Wuhan Textile University, Wuhan, China
Keywords
Enzyme activities; Farm manure; Gypsum; Land use; Mineralization; Saline and alkaline soils; Soil amelioration
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