BackgroundSale of organic foods is one of the fastest growing market segments within the global food industry. People often buy organic food because they believe organic farms produce more nutritious and better tasting food from healthier soils. Here we tested if there are significant differences in fruit and soil quality from 13 pairs of commercial organic and conventional strawberry agroecosystems in California.Methodology/Principal FindingsAt multiple sampling times for two years, we evaluated three varieties of strawberries for mineral elements, shelf life, phytochemical composition, and organoleptic properties. We also analyzed traditional soil properties and soil DNA using microarray technology. We found that the organic farms had strawberries with longer shelf life, greater dry matter, and higher antioxidant activity and concentrations of ascorbic acid and phenolic compounds, but lower concentrations of phosphorus and potassium. In one variety, sensory panels judged organic strawberries to be sweeter and have better flavor, overall acceptance, and appearance than their conventional counterparts. We also found the organically farmed soils to have more total carbon and nitrogen, greater microbial biomass and activity, and higher concentrations of micronutrients. Organically farmed soils also exhibited greater numbers of endemic genes and greater functional gene abundance and diversity for several biogeochemical processes, such as nitrogen fixation and pesticide degradation.Conclusions/SignificanceOur findings show that the organic strawberry farms produced higher quality fruit and that their higher quality soils may have greater microbial functional capability and resilience to stress. These findings justify additional investigations aimed at detecting and quantifying such effects and their interactions.

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Biodynamic agriculture is a unique organic farming system that utilizes, in addition to the common tools of organic agriculture, specific fermented herbal preparations as compost additives and field sprays. The objective of this work was to determine whether biodynamic compost or field spray preparations affect the soil biological community in the short term, beyond the effects of organic management. Four fertilizer options: (i) composted dairy manure and bedding (organic fertilization), (ii) the same material composted with biodynamic compost preparations, (iii) mineral fertilizers, and (iv) no fertilizer were investigated with and without the biodynamic field spray preparations. Both biodynamic and nonbiodynamic composts increased soil microbial biomass, respiration, dehydrogenase activity, soil C mineralized in 10 d (MinC), earthworm (Lumbricus terrestris) population and biomass, and metabolic quotient of respiration per unit biomass (qCO2) by the second year of study. No significant differences were found between soils fertilized with biodynamic vs. nonbiodynamic compost. Use of biodynamic field sprays was associated with more MinC and minor differences in soil microbial fatty acid profiles in the first year of study. There were no other observed effects of the biodynamic preparations. Organically and biodynamically managed soils had similar microbial status and were more biotically active than soils that did not receive organic fertilization. Organic management enhanced soil biological activity, but additional use of the biodynamic preparations did not significantly affect the soil biotic parameters tested.

N made available to crops that follow legumes in rotation. An estimate of soil mineralizable N is needed to determine crop While fertilization guides use total organic matter and needs for N fertilizer. The objective of this research was to estimate previous crop as indicators of N mineralization for the soil net N mineralization in soils maintained in continuous corn (Zea mays L.) (CC), corn-soybean [Glycine max (L.) Merr.] (CS), and coming season, a variety of direct and indirect lab methcorn-soybean-wheat (Triticum aestivum L.)/alfalfa (Medicago sativa ods may be used for more precise predictions (Fox and L.)-alfalfa (CSWA) rotations that have been managed since 1990 Piekielek, 1978; Hong et al., 1990). Laboratory tests with zero N (0N), low N (LN), and high N (HN) fertilization. Soil allow compositing and homogenizing soil samples to samples were taken from 0-to 20-cm depth in plots planted to corn decrease the standard deviation and required replicain 1998. In order to produce more realistic time-series data of net N tion. Aerobic incubation for 120 to 252 d is commonly mineralization, soils were incubated in filtration units in a variableused to estimate the size and decay rates of mineraliztemperature incubator (VTI) that mimicked field soil temperatures able N pools (Stanford and Smith, 1972; Cabrera and under a growing corn canopy. Rotation and N fertilization significantly Kissel, 1988). Temperature and matric potential of incuaffected net N mineralization in soil samples. Cumulative net N minerbated soils affect the rate and cumulative N mineralized. alized in a 189-d field temperature incubation averaged 133 Ϯ 6 kg ha Ϫ1 in CC, 142 Ϯ 5 kg ha Ϫ1 in CS, and 189 Ϯ 5 kg ha Ϫ1 in CSWA. Within ordinary field soil matric potentials from Ϫ1.85 Across rotations, average net N mineralized was 166 Ϯ 9 kg ha Ϫ1 in to Ϫ0.01 MPa, temperature has a greater influence on 0N plots, 147 Ϯ 10 kg ha Ϫ1 in LN plots, and 152 Ϯ 10 kg ha Ϫ1 in N mineralization than does matric potential (Zak et al., HN plots. Inclusion of a legume, particularly alfalfa, in the rotation 1999). Most N mineralization laboratory experiments increased net N mineralized. Generally, more net N was mineralized are incubated at 35ЊC, considered the ideal temperature from plots receiving no fertilizer N than from soil with a history of for maximum N mineralization. Nitrogen mineralized N fertilization. Variable-temperature incubation produced realistic in laboratory incubations at 35ЊC represents potential time-series data with low sample variability.