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United States Department of Agriculture

Agricultural Research Service

Title: Carbon and Nitrogen Pools of Southern High Plains Cropland and Grassland Soils.

Authors
item Bronson, K - TEXAS A&M UNIVERSITY
item Zobeck, Teddy
item Chua, T - TEXAS A&M UNIVERSITY
item Acosta-Martinez, Veronica
item Van Pelt, Robert
item Booker, J - TEXAS A&M UNIVERSITY

Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 6, 2004
Publication Date: January 6, 2004
Citation: Bronson, K.F., Zobeck, T.M., Chua, T.T., Acosta Martinez, V., Booker, J.D. 2004. Carbon and nitrogen pools of southern High Plains cropland and grassland soils. Soil Science Society of America Journal. 68:1695-1704.

Interpretive Summary: Carbon (C )and nitrogen (N) are important soil properties that have long been recognized as indicators of soil productivity. The current low levels of soil C and N of cropland soils have led to interest in storing C with reduced tillage cropping systems and with the Conservation Reserve Program (CRP). Our objective was to determine the effects of cropping systems on C and N in soils of the Southern High Plains. The surface soils of three cotton systems and native rangeland and CRP were compared. Total soil C and N in CRP were greater than in cropland soils only in the 0-2 inches (0-5 cm) surface layer. The relatively short time the CRP sites were in place (9-15 yr) apparently limited C and N storage. New management practices, such as irrigating winter cover crops, need to be tested for their effect on C and N storage in conservation-tillage cotton systems in the Southern High Plains.

Technical Abstract: Carbon and N contents in soils have long been recognized as important indicators of soil productivity. The current low levels of soil C and N of cropland soils have led to interest in sequestering C with reduced tillage cropping systems and with the Conservation Reserve Program (CRP). Our objective was to determine the effect of agroecosystem on soil C and N pools in the Southern High Plains. These included three cotton (Gossypium hirsutum L.) cropping systems and two grassland systems (CRP or native rangeland (NR)). We sampled 0-5, 5-10, 10-20, and 20-30 cm soil depths at eleven farm sites in four counties. Each system had five or six replicates or farm sites. Total soil C and N, particulate organic matter (POM)-C and 'N, ' 13C of POM and whole soil, potentially mineralizable C and N, water-extractable-C (WEC), and extractable NH4 and NO3 were determined. Total C and N in the 0-30 cm soil profile was 34.3 Mg C ha-1 and 2.5 Mg N ha-1 for NR, and 22.9 Mg C ha-1 and 1.9 Mg N ha-1 for cropland systems, respectively. Total soil C and N in CRP were greater than in cropland soils only in the 0-5 cm surface layer. Labile C and N pools were positively correlated with each other and with total soil C and N. The relatively short time the CRP sites were in place (9-15 yr) apparently limited C and N sequestration. New management practices, such as irrigating winter cover crops, need to be tested for their effect on C and N sequestration in conservation-tillage cotton systems in the Southern High Plains.

Last Modified: 4/16/2014