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Growing demand for soybean [Glycine max (L.) Merr.] creates pressure to expand soybean production onto marginal lands and grow soybean continuously. Experiments comparing continuous soybean with soybean–corn (Zea mays L.) rotation, cereal rye [Secale cereale (L.)] cover crop with no cover crop, and flue‐gas desulfurization (FGD) gypsum surface‐applied at 0, 1.1, and 2.2 Mg ha−1 were conducted at Shorter, AL, Farmland, IN, Hoytville, OH, and Piketon, OH, for 5 yr. The objective was to evaluate soybean yield response to these practices across a range of soil types and climatic conditions. Response to continuous soybean and cover crop varied by site (soil drainage class) with no interaction effects. Continuous soybean reduced yield only on well‐ and moderately well‐drained soil types. Cover crop reduced yield on the very poorly drained soil type and increased yield on the well‐drained soil type. Crop production practices that promote soil health and sustainability may not provide yield improvement.

Objective To assess the true association between appropriate prescription of antibiotics and prognosis in patients with sepsis, a key issue in health care and quality improvement strategies. Methods Prospective cohort study in three university hospitals to determine whether the empirical prescription of antibiotics was adequate or inadequate, and to compare hospital death rates and length of stay according to different classifications of antibiotics prescription. Logistic regression models for risk estimation were fitted. Results A total of 705 patients with severe sepsis were included. No differences were found in positive-culture patients (n = 545) regarding the risk of death with insufficient spectrum antibiotics, compared to patients who received adequate spectrum antibiotics (OR = 0.90; 95% CI = 0.55-1.48). Delay in initiating antibiotics was not associated with the risk of death in patients with adequate spectrum of antibiotics, either with positive (OR = 1.04; 95% CI = 0.99-1.08) or negative cultures (OR = 0.98; 95% CI = 0.92-1.04). There were no differences in the length of hospital stay, according to the antibiotic prescription (median 11 days, IQR = 7-18 days for the whole cohort). Conclusions No associations were found between inadequate antibiotic prescription or delay to initiate therapy and mortality or length of stay.

Acid weathered soils often require lime and fertilizer application to overcome nutrient deficiencies and metal toxicity to increase soil productivity. Slow-pyrolysis chicken manure biochars, produced at 350 and 700°C with and without subsequent steam activation, were evaluated in an incubation study as soil amendments for a representative acid and highly weathered soil from Appalachia. Biochars were mixed at 5, 10, 20, and 40 g kg into a Gilpin soil (fine-loamy, mixed, active, mesic Typic Hapludult) and incubated in a climate-controlled chamber for 8 wk, along with a nonamended control and soil amended with agronomic dolomitic lime (AgLime). At the end of the incubation, soil pH, nutrient availability (by Mehlich-3 and ammonium bicarbonate diethylene triamine pentaacetic acid [AB-DTPA] extractions), and soil leachate composition were evaluated. Biochar effect on soil pH was process- and rate-dependent. Biochar increased soil pH from 4.8 to 6.6 at the high application rate (40 g kg), but was less effective than AgLime. Biochar produced at 350°C without activation had the least effect on soil pH. Biochar increased soil Mehlich-3 extractable micro- and macronutrients. On the basis of unit element applied, increase in pyrolysis temperature and biochar activation decreased availability of K, P, and S compared to nonactivated biochar produced at 350°C. Activated biochars reduced AB-DTPA extractable Al and Cd more than AgLime. Biochar did not increase NO in leachate, but increased dissolved organic carbon, total N and P, PO, SO, and K at high application rate (40 g kg). Risks of elevated levels of dissolved P may limit chicken manure biochar application rate. Applied at low rates, these biochars provide added nutritional value with low adverse impact on leachate composition.

Introduction Although high-performance liquid chromatography with ultraviolet detection (HPLC-PAD) is widely available, it has not been used for artemisinin (1) analysis because of the lack of UV absorption reported for this lactone. Increased Artemisia annua cultivation for production of 1 requires an affordable and reliable method to analyse 1 and its precursors dihydroartemisinic acid (2) and artemisinic acid (3) simultaneously from underivatized plant extracts. Objective To validate HPLC-PAD for the quantification of underivatized artemisinin from A. annua and artemisinin-based drugs. Methodology Dried A. annua leaves were extracted with petroleum ether, dried, reconstituted in acetonitrile, and analysed by HPLC-PAD at 192 nm using an isocratic mobile phase (60:40, acetonitrile:0.1% acetic acid). HPLC-PAD was evaluated through accuracy, precision, recovery and comparison with HPLC with evaporative light scattering detection (HPLC-ELSD). Results HPLC-PAD proved accurate, precise and reproducible for the direct quantification of 1 and related compounds, and was more sensitive than ELSD for most of the compounds tested. The limit of quantification of 1–3 from plants was 0.048, 0.024 and 0.008 g/100 g dry weight, respectively. Recoveries were over 98%, with good intra- and inter-day repeatability. HPLC-PAD correlated significantly (r2 = 0.99, p

An understanding of organic C dynamics in soils is necessary to develop management options to enhance soil organic C sequestration. The objective of this research was to study the distribution of newly formed humic materials into mineralogically distinct clay-size fractions of a silt loam soil. Oats (Avena sativa L. cv. Ogle), grown under simulated no-tillage conditions, were pulse labeled with 14 CO 2 . After senescence, the labeled surface residue was removed and replaced with unlabeled residue and the labeled roots were allowed to decompose in the soil for 360 d. The soil clay fraction (

Nicosulfuron (2-[[[[(4,6-dimethoxy-2-pyrimidinyl)amino]carbonyl]amino]sulfonyl]-N,N-dimethyl-3-pyridinecarboxamide is a relatively new sulfonylurea promoted for weed control in corn (Zea mays L.). However, there are no published studies on its transport and mobility in soils. In this study, breakthrough curves (BTCs) were measured using soil columns for eight Iowa soils and four Oxisols from Brazil. Chloride (Cl ) and pentafluorobenzoic acid (PFBA) were used as nonreactive tracers. For the sandy Iowa soils and the Brazilian soils BTCs were symmetrical, while for the nonsandy Iowa soils BTCs were asymmetrical. Breakthrough curves were interpreted using convection-dispersion equation and equilibrium and nonequilibrium transport models. In Brazilian soils and sandy Iowa soils equilibrium models described the BTCs well. In nonsandy Iowa soils, where tailing was observed, the data were better described by a two-site/ two-region model, indicative of nonequilibrium processes. A comparison with the Cl and PFBA BTCs suggests that the nonequilibrium is not transport-related. This is also supported by the low correlation between the mass transfer parameters and the partition coefficients. It is proposed that the observed nonequilibrium in nonsandy Iowa soils is most likely due to nicosulfuron chemisorption on smectites. The results of this study indicate that due to rapid sorption of nicosulfuron on smectites its potential to leach to the groundwater should be relatively low in the loamy and clayey soils that contain expandable 2:1 layer silicates.

Nicosulforon (2-[[[[(4,6-dimethoxy-2-pyrimidinyl)amino]carbonyl]amino]sulfonyl]-N,N-dimethyl-3-pyridinecarboxamide) is a new, low-rate, sulfonylurea herbidde that is being promoted for weed control in corn (Zea mays L.) ; however, there is a lack of published information on its behavior in soils. In this study nicosulfuron sorption was measured in batch experiments, at a 1 :2 soil/solution ratio, for 10 Iowa and four Brazilian soils. Adsorption isotherms were nonlinear with K t,ads values ranging from 0.21 to 8.78 with the highest values obtained for Iowa soils. Nicosulfuron K t,ads values in Iowa soils were correlated with clay content (r = 0.92), while in Brazilian soils the K t,ads values were correlated with organic C content (r = 0.97). These differences are interpreted in terms of different clay mineralogy of Iowa (expandable 2 :1 clay minerals) and Brazilian soils (kaolinite, Al and Fe oxides). Nicosulfuron desorption isotherms, obtained using one-step extraction with 5 x 10 -3 M CaCl 2 , were nearly single valued with adsorption isotherms in soils with pH >5.5, while hysteresis was observed in soils with pH < 5.5. Up to 100% of the nicosulfuron was desorbed from Brazilian soils in one desorption step with a 2 :1 acetonitrile/water mixture. Only 50 to 70% of adsorbed nicosulfuron could be desorbed with the same extractant from Iowa soils, possibly due to chemisorption of nicosulfuron on 2 :1 clay minerals. This study suggests that nicosulfuron will not be highly mobile in the soils with a 2 :1 clay mineralogy indicating that in such soils its potential to leach to groundwater may be lower than that of other sulfonylurea herbicides.