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United States Department of Agriculture

Agricultural Research Service

Title: Early Impacts of Cotton and Peanut Cropping Systems on a Sandy Soil: Organic Matter, Aggregate Stability, Microbial Biomass, and Enzyme Activities

Authors
item Acosta-Martinez, Veronica
item Upchurch, Dan
item Schubert, A - TAEX, LUBBOCK, TX
item Porter, D - TAEX, LUBBOCK, TX
item Wheeler, T - TAEX, LUBBOCK, TX

Submitted to: Biology and Fertility of Soils
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 24, 2002
Publication Date: March 20, 2004
Citation: Acosta Martinez, V., Upchurch, D.R., Schubert, A.M., Porter, D., Wheeler, T. 2004. Early impacts of cotton and peanut cropping systems on a sandy soil: organic matter, aggregate stability, microbial biomass, and enzyme activities. Biology and Fertility of Soils. 40: 44-54.

Interpretive Summary: This study investigated the early impacts of cotton (Gossypium hirsutum L.) (=Ct) and peanut (Arachis hypogaea L.) (=Pt) cropping systems on a Brownfield fine sandy soil (loamy, mixed, superactive, thermic Arenic Aridic Paleustalfs). The study was conducted in the West Texas area of the United States. The soil contains 91% sand, 2% silt, and 7% clay. Samples (0-12 cm) were taken during the first two years of the initiation of the study from continuous peanut (PtPtPt) and peanut and cotton rotations (CtCtPt and PtCtCt) that were under 50, 75, and 100% evapotranspiration (ET) irrigation level treatments. The samplings were conducted in March, June, and September 2002, and March 2003. Soil total N and aggregate stability were not different among the cropping systems. The pH of the soils was > 8.0, and lowest in PtPtPt. Continuous peanut increased soil organic C, microbial biomass (Cmic) and different enzyme activities of the C, N, S, and P cycling compared to continuous cotton and peanut-cotton rotation. Between the two sources of arylsulfatase activity in soil, the intracellular activity (inside microorganisms) was affected by the cropping systems, but not the extracellular (attached to soil surfaces) activity. The microbial biomass and enzyme activities showed different seasonal variations. Microbial biomass C (Cmic) increased during September and it was maintained through March 2003. Enzyme activities were similar during the study for CtCtPt and PtCtCt, but showed a decrease from March to June for PtPtPt. Principal Component Analysis (PCA) demonstrated different fatty acids methyl ester (FAME) profiles, indicator of the microbial community structure, due to time of sampling. Multivariate analyses of variance (MANOVA) showed that the fungi indicator fatty acids (18:2w6c and 18:1w9c) and bacteria indicator fatty acids (15:0, a15:0, and a17:0) were more predominant in PtPtPt than in CtCtPt and PtCtCt. Because continuous peanut is not a long-term sustainable system, our findings provide indications that other crops may be more suitable for rotations with peanut in sandy soils of Texas in order to impact its microbiological and biochemical properties.

Technical Abstract: This study investigated the impacts of cropping systems of cotton (Gossypium hirsutum L.) (=Ct) and peanut (Arachis hypogaea L.) (=Pt) on a Brownfield fine sandy soil (loamy, mixed, superactive, thermic Arenic Aridic Paleustalfs) with 91% sand, 2% silt, and 7% clay. The study was conducted in West Texas. Samples (0-12 cm) were taken during the first three years from PtPtPt, CtCtPt and PtCtCt. The sampling times were in March, June, and September 2002, and March 2003. Soil total N and aggregate stability were not different among the cropping systems. The pH of the soils was greater than 8.0, and lowest in PtPtPt. Continuous peanut increased soil organic C, microbial biomass C (Cmic) and the activities of beta-glucosidase, beta-glucosaminidase, acid phosphatase, alkaline phosphatase, and phosphodiesterase compared to continuous cotton and peanut-cotton rotation. The intracellular and total arylsulfatase activities showed the same trend, but the extracellular activity was unaffected by the cropping systems. Soil enzyme activities were similar in CtCtPt and PtCtCt during the study, but there was a decrease from March to June in PtPtPt. Soil microbial biomass C (Cmic) showed different seasonal variation during the study. Principal Component Analysis (PCA) demonstrated differences in soil fatty acids methyl ester (FAME) profiles due to time of sampling, and multivariate analyses of variance (MANOVA) showed fungi indicator fatty acids (18:2w6c and 18:1w9c) and the bacteria indicator fatty acids (15:0, a15:0, and a17:0) were higher in PtPtPt than in CtCtPt and PtCtCt.

Last Modified: 11/26/2014
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