Submitted to: Biology and Fertility of Soils
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/11/2007
Publication Date: 5/1/2008
Citation: Acosta Martinez, V., Rowland, D., Sorensen, R.B., Yeater, K.M. 2008. Microbial community structure and functionality under peanut based cropping systems in a sandy soil. Biology and Fertility of Soils. 44(5):681-692. Interpretive Summary: Little information is available about soil microorganisms as affected by different peanut (Arachis hypogaea L.) cropping systems and how they relate to soil functioning. Peanut is typically produced in sandy soils, which have lower numbers and diversity of microbial populations and nutrient availability compared to soils with higher clay and OM contents. Thus, management decisions are critical to improve soil quality. USDA-ARS scientists from the Cropping Systems Research Laboratory (Lubbock, TX) and National Peanut Research Laboratory (Dawson, GA) studied a loamy sand (fine-loamy, kaolinitic, thermic Plinthic Kandiudults) under different peanut cropping systems in Georgia, which is first in peanut production in U.S. After 5 and 8 years, soils under cotton based cropping systems (continuous cotton and cotton-cotton-peanut) showed lower microbial populations, mycorrhiza, and enzyme activities of C and P cycling compared to peanut based cropping systems (corn-peanut-cotton, peanut-peanut-cotton, and continuous peanut). These findings should be considered in the selection of cropping systems to maintain and/or improve soil quality, functionality, and sustainability of agricultural production.
Technical Abstract: Little information is available on soil microbial and biochemical properties, important for understanding nutrient cycling and organic matter (OM) dynamics, as affected by different peanut cropping systems and how they relate to soil functioning. Thus, we studied a Tifton loamy sand (fine-loamy, kaolinitic, thermic Plinthic Kandiudults) in Georgia, which is first in peanut production in U.S., after 5 and 8 years under continuous cotton (Gossypium hirsutum, L) (CtCtCt), cotton-cotton-peanut (CtCtPt), corn (Zea mays L.)-peanut-cotton (CrPtCt), peanut-peanut-cotton (PtPtCt), and continuous peanut (PtPtPt). Soil organic carbon (OC) at 0-20 cm was already higher under PtPtPt (avg: 8.7 g C kg-1 soil), PtPtCt (avg: 7.7 g C kg-1 soil) and CrPtCt (avg: 7.8 g C kg-1 soil) compared with CtCtPt (avg: 4.7 g C kg-1 soil) and CtCtCt (avg: 3.3 g C kg-1 soil). Similarly, alkaline phosphatase, acid phosphatase and phosphodiesterase as a group showed higher activities under PtPtPt, PtPtCt and CrPtCt than under CtCtPt and CtCtCt. The activities of glycosidases (''-galactosidase, '-glucosidase, and '-glucosaminidase) as a group were more sensitive to the cropping systems than phosphastases, and showed a distinctive cropping system separation as follows: PtPtPt=CrPtCt>PtPtCt>CtCtPt>CtCtCt. Similar to OC and MBC trends, distinctive differences were found in the microbial community structure of this sandy soil after 8 years between peanut-based cropping systems (CrPtCt, PtPtCt and PtPtPt) and cotton-based cropping systems (CtCtCt and CtCtPt) as indicated by the fatty acid methyl esters (FAME) profiles.