Cover crops and compost are organic matter inputs that can impact soil health in tillage-intensive, high-input, organic vegetable production systems in the central coast region of California. Data are presented on soil microbial biomass (carbon and nitrogen) and soil enzymes (β-glucosidase, β-glucosaminidase, alkaline phosphatase, aspartase and L-asparaginase and dehydrogenase) from a relatively long-term organic systems experiment in Salinas, California that was focused on lettuce and broccoli production and included eight different certified organic systems. These systems differed in compost inputs, cover cropping frequency, cover crop type, and cover cropping seeding rate.
View Article and Find Full Text PDFSorghum ( Moench, L.) plant accumulates copious layers of epi-cuticular wax (EW) on its aerial surfaces, to a greater extent than most other crops. EW provides a vapor barrier that reduces water loss, and is therefore considered to be a major determinant of sorghum's drought tolerance.
View Article and Find Full Text PDFCarbon nanotubes (CNTs) may affect bioavailability and toxicity of organic contaminants due to their adsorption properties. Recent studies have observed the influence of multiwalled carbon nanotubes (MWNTs) on the fate of polycyclic aromatic hydrocarbons (PAHs) and other organic contaminants. Greenhouse studies (49 d) were conducted with alfalfa plants in two different soil types.
View Article and Find Full Text PDFSoil microbial communities in Chihuahuan Desert grasslands generally experience highly variable spatiotemporal rainfall patterns. Changes in precipitation regimes can affect belowground ecosystem processes such as decomposition and nutrient cycling by altering soil microbial community structure and function. The objective of this study was to determine if increased seasonal precipitation frequency and magnitude over a 7-year period would generate a persistent shift in microbial community characteristics and soil nutrient availability.
View Article and Find Full Text PDFThis study evaluated the impacts of multiwalled carbon nanotubes (MWNTs) on microbial community composition and functioning in a sandy loam soil over 90 d. We used test concentrations in the range of lower MWNT concentrations (10mg/kg) to extremely high MWNT concentrations (10,000 mg/kg) as a worst case scenario. We observed no effects of MWNTs on soil respiration, enzymatic activities, and microbial community composition at 10, 100 and 1,000 mg/kg.
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