Management Impacts on Soil Organic Matter of Tropical Soils

Author(s)

Castro, Gustavo S. A. ^[1] ; Crusciol, Carlos A. C. ^[2] ; Calonego, Juliano C. ^[3] ; Rosolem, Ciro A. ^[2]

Affiliation

^[1] Brazilian Agr Res Corp, EMBRAPA, BR-68903419 Macapa, State Of Amapa - Brazil

^[2] Sao Paulo State Univ, UNESP, Coll Agr Sci, Dept Crop Sci, BR-18603970 Botucatu, SP - Brazil

^[3] Ctr Agr Sci UNOESTE, BR-19067175 Presidente Prudente, SP - Brazil

• Document type: Journal article
• Source: VADOSE ZONE JOURNAL; v. 14, n. 1 JAN 2015.
• Web of Science Citations: 15

Abstract

Increased soil organic matter (SOM) improves the cation exchange capacity of tropical weathered soils, and liming is required to achieve high yields in these soils. Despite a decrease in SOM in the short term, liming may increase SOM with time by improving cation chemical bonds with soil colloids. Soil C may also be increased in high dry matter input cropping systems. We evaluated C changes in a Typic Rhodudalf as affected by four production systems with increasing residue inputs, with or without limestone or silicate. Soil use intensification by increasing the number of species in rotation as well as acidity remediation resulted in higher plant residue production. Introducing a green manure or a second crop in the system increased plant residue by 89% over fallow, but when a forage crop was used, plant residues more than doubled. Soil acidity amelioration increased plant residue deposition by 21% over the control. The introduction of a forage crop increased labile SOM and C contents in the particulate fraction, and lime or silicate application led to increases in the more stable SOM fraction. High amounts of plant residues (>70 Mg ha(-1) in 5 yr) are effective in raising soil labile C, but the alleviation of soil acidity results in increased soil stable C irrespective of crop rotations in tropical weathered soils, and in this case plant residue deposition can be lower. Lime and silicate are equally effective in alleviating soil acidity and increasing soil C, probably due to the formation of cation bridges with soil colloids. (AU)

• FAPESP's process: 09/10232-0 - Physical and chemical modifications and organic matter fractionation as affected by crop system and superficial liming and silicate application
• Grantee: Carlos Alexandre Costa Crusciol
• Support Opportunities: Regular Research Grants
• FAPESP's process: 09/05066-4 - Physical and chemical modifications and organic matter fractionation as affected by crop system and superficial liming and silicate application
• Grantee: Gustavo Spadotti Amaral Castro
• Support Opportunities: Scholarships in Brazil - Doctorate