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Microbial Community Composition as Affected by Dryland Cropping Systems and Tillage in a Semiarid Sandy Soil
USDA-ARS, Cropping Systems Research Laboratory, Wind Erosion and Water Conservation Unit, 3810 4th St., Lubbock, TX 79415, USA
Research and Testing Laboratories and Medical Biofilm Research Institute, 4321 Marsha Sharp Freeway, Lubbock, TX 79407, USA
Department of Biological Sciences, Texas Tech University, Lubbock, TX 79409, USA
USDA-ARS, Southern Plains Area, 1001 Holleman Drive East, College Station, TX 77840-4117, USA
* Author to whom correspondence should be addressed.
Received: 19 April 2010; in revised form: 28 May 2010 / Accepted: 1 June 2010 / Published: 7 June 2010
Abstract: This study evaluated microbial communities of soil (0–10 cm) as affected by dryland cropping systems under different tillage practices after 5 years. The soil type was an Olton sandy loam with an average of 16.4% clay, 67.6% sand and 0.65 g kg−1 of organic matter (OM). The cropping systems evaluated were grain sorghum (Sorghum bicolor L.)—cotton (Gossypium hirsutum) (Srg-Ct), cotton-winter rye (Secale cereale)-grain sorghum (Ct-Rye-Srg), and a rotation of forage (f) sorghum (Sorghum bicolor L. and Sorghum sudanense) with winter rye (Srf-Rye), which were under no-tillage (nt) and conventional tillage (ct) practices. Soil microbial communities under cotton based cropping systems (Srg-Ct and Ct-Rye-Srg) showed lower fungal:bacterial ratios compared to the soil under Srf-Rye. Soil under Srf-Rye showed higher population densities of Bacteroidetes and Proteobacteria while lower Actinobacteria compared to Srg-Ct and Ct-Rye-Srg. Chloroflexi, Gemmatimonadetes and Verrucomicrobiae were higher in tilled soil compared to the no-tilled plots. Regardless the limited irrigation available to sustain agricultural production within these dryland cropping systems, this study demonstrated that differences in microbial communities are more affected by crop rotation than tillage management history. Although soil fungal diversity was not analyzed in this study, pyrosequencing suggests that tillage practices can affect bacterial phyla distribution in this sandy soil.
Keywords: pyrosequencing; soil microbial communities; bacterial diversity; FAME analysis; enzyme activities; cropping systems; tillage; GRACEnet
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Acosta-Martínez, V.; Dowd, S.E.; Bell, C.W.; Lascano, R.; Booker, J.D.; Zobeck, T.M.; Upchurch, D.R. Microbial Community Composition as Affected by Dryland Cropping Systems and Tillage in a Semiarid Sandy Soil. Diversity 2010, 2, 910-931.
Acosta-Martínez V, Dowd SE, Bell CW, Lascano R, Booker JD, Zobeck TM, Upchurch DR. Microbial Community Composition as Affected by Dryland Cropping Systems and Tillage in a Semiarid Sandy Soil. Diversity. 2010; 2(6):910-931.
Acosta-Martínez, Verónica; Dowd, Scot E.; Bell, Colin W.; Lascano, Robert; Booker, Jill D.; Zobeck, Ted M.; Upchurch, Dan R. 2010. "Microbial Community Composition as Affected by Dryland Cropping Systems and Tillage in a Semiarid Sandy Soil." Diversity 2, no. 6: 910-931.