Submitted to: American Peanut Research and Education Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 7/13/2004
Publication Date: 7/16/2004
Citation: Acosta Martinez, V., Rowland, D., Sorensen, R.B. 2004. Impacts of cotton and peanut cropping systems on the microbial and biochemical properties of a sandy soil in georgia[abstract]. American Peanut Research and Education Society.
Technical Abstract: Little is known about the impacts of cotton (Gossypium hirsutum L.) and peanut (Arachis hypogaea L.) cropping systems on the soil chemical, microbial and biochemical properties. This information is important to understand the crop-soil system sustainability and environmental impacts. This study investigated the impacts of cotton (=Ct) and peanut (=Pt) cropping systems on a Tifton sandy loam soil (fine-loamy, kaolinitic, thermic Plinthic Kandiudults) after 5 years of the establishment of the plots in Georgia, USA. Soil surface samples (0-22.5 cm) were taken in April, June, and September of 2002 from plots under PtPtPt, CtCtPt, and PtPtCt. The soil contained 80% sand, 13% clay, and 8% silt with an average pH of 6.3. Our study found that soil organic C was higher under PtPtPt (avg: 8.7 g C kg-1 soil) and PtPtCt (avg: 7.7 g C kg-1 soil) compared to CtCtPt (avg: 4.7 g C kg-1 soil). A similar trend was found for soil total N content. Enzyme activities, involved in nutrient cycling, such as '-glucosidase, '-glucosaminidase, acid phosphatase, alkaline phosphatase, and phosphodiesterase activities were higher in soils under PtPtPt than in PtPtCt and CtCtPt in April. In June and September, most of the enzyme activities showed this significant (P<0.05) trend: PtPtPt> PtPtCt> CtCtPt. The soil microbial biomass C and N were generally higher in PtPtPt and PtPtCt compared to CtCtPt. For this soil, in contrast to soils with lower sand content, the continuous monoculture system (PtPtPt) tended to promote soil chemical, microbial, and biochemical properties compared to crop rotations. These results are not in agreement with the sustainability problems of continuous monoculture systems. However, there was also an enhancement of the soil microbial and biochemical properties in the crop rotation that involved two consecutive years of peanut (PtPtCt) compared to the crop rotation with only one year of peanut (CtCtPt).