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Carbon Supply and Storage in Tilled and Nontilled Soils as Influenced by Cover Crops and Nitrogen Fertilization
Author(s) -
Sainju Upendra M.,
Singh Bharat P.,
Whitehead Wayne F.,
Wang Shirley
Publication year - 2006
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2005.0189
Subject(s) - vicia villosa , cover crop , agronomy , loam , secale , sorghum , soil carbon , tillage , environmental science , no till farming , soil water , biology , soil fertility , soil science
Soil carbon (C) sequestration in tilled and nontilled areas can be influenced by crop management practices due to differences in plant C inputs and their rate of mineralization. We examined the influence of four cover crops {legume [hairy vetch ( Vicia villosa Roth)], nonlegume [rye ( Secale cereale L.)], biculture of legume and nonlegume (vetch and rye), and no cover crops (or winter weeds)} and three nitrogen (N) fertilization rates (0, 60 to 65, and 120 to 130 kg N ha −1 ) on C inputs from cover crops, cotton ( Gossypium hirsutum L.), and sorghum [ Sorghum bicolor (L.) Moench)], and soil organic carbon (SOC) at the 0‐ to 120‐cm depth in tilled and nontilled areas. A field experiment was conducted on Dothan sandy loam (fine‐loamy, siliceous, thermic Plinthic Paleudults) from 1999 to 2002 in central Georgia. Total C inputs to the soil from cover crops, cotton, and sorghum from 2000 to 2002 ranged from 6.8 to 22.8 Mg ha −1 The SOC at 0 to 10 cm fluctuated with C input from October 1999 to November 2002 and was greater from cover crops than from weeds in no‐tilled plots. In contrast, SOC values at 10 to 30 cm in no‐tilled and at 0 to 60 cm in chisel‐tilled plots were greater for biculture than for weeds. As a result, C at 0 to 30 cm was sequestered at rates of 267, 33, −133, and −967 kg C ha −1 yr −1 for biculture, rye, vetch, and weeds, respectively, in the no‐tilled plot. In strip‐tilled and chisel‐tilled plots, SOC at 0 to 30 cm decreased at rates of 233 to 1233 kg C ha −1 yr −1 The SOC at 0 to 30 cm increased more in cover crops with 120 to 130 kg N ha −1 yr −1 than in weeds with 0 kg N ha −1 yr −1 , regardless of tillage. In the subtropical humid region of the southeastern United States, cover crops and N fertilization can increase the amount of C input and storage in tilled and nontilled soils, and hairy vetch and rye biculture was more effective in sequestering C than monocultures or no cover crop.