Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/2/2004
Publication Date: 2/2/2004
Citation: Acosta Martinez, V., Zobeck, T.M., Allen, V. 2004. Soil properties in continuous cotton and an alternative integrated crop-livestock systems. Soil Science Society of America Journal. 68:1875-1884. Interpretive Summary: The production of cotton in Texas Southern High Plains region has some problems that need to be solved. First, cotton produced continuously with tillage reduces soil organic matter, and this makes the soil more easily eroded by wind. Another problem is that cotton has used irrigation with water from the Ogallala aquifer, but this aquifer is having less water available over the years. Even though a lot of cattle exist in Texas, cotton production has not been integrated with livestock production, which may require less water and may benefit soils. An alternative integrated crop livestock system we studied showed more microorganisms (fungi and bacteria), activities, and in most cases organic matter in soil in comparison with the continuous cotton. These results suggest there are benefits in soil under a crop and livestock system.
Technical Abstract: Several properties were compared on a Pullman soil (Fine, mixed, thermic Torrertic Paleustolls) at 0-5, 5-10, and 10-15 cm depths at the end of 5 years under a continuous cotton monoculture system (CCM System) and an alternative integrated-livestock system (AICL system) of perennial grass pasture (Bothriochloa bladhii) and a rye (Secale cereale)-cotton (Gossypium hirsutum)-wheat (Triticum aestivum)-fallow rotation during two samplings. At 0-5 cm depth, total N (avg: 1.0 g kg-1 soil) remained similar among systems, soil pH was > 8.1, and organic C was greater in perennial pasture (13.5 g kg-1 soil) compared to CCM system (9.0 g kg-1 soil). The same trend of organic C was observed for aggregate stability. In July, Cmic was greater in perennial pasture (193 mg kg-1 soil) and the rotation under rye and cotton (237 mg kg-1 soil) compared to CCM system (124 mg kg-1 soil), and it was also greater in perennial pasture at 5-10 and 10-15 cm depths. Soil Nmic showed similar trends. b-glucosaminidase, b-glucosidase, and total (extracellular and intracellular) arylsulfatase activities were greater in perennial pasture and the rotation (under rye and cotton) than CCM system at 0-5 cm. The intracellular arylsulfatase activity (55-84%) was more predominant than the extracellular pool. Total arylsulfatase protein content was greater in AICL system (24.7 mg kg-1 soil) than in CCM system (13.6 mg kg-1 soil). FAME profiles of perennial pasture were separated from the other systems at all soil depths along PC2 (19%). AICL system showed higher abundance of indicator fatty acids of protozoa (20:4w6c avg: 1.98%) or fungi (18:3w9c= 1.30%) than CCM system (20:4w6c =1.09%; 18:3w9c= 0.76%). The results suggest improved soil function and sustainability of AICL system compared to CCM system.