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Plant growth and residue decomposition values are needed by the Soil Conservation Service for developing data bases for selected fruit and vegetable crops. These data bases will be used for predicting soil loss using improved erosion prediction technology. The plant growth parameters under investigation are canopy cover leaf area index, plant height plant weight, root weight, stem diameter and vegetative dry matter. The climatic parameter are daily base temperature rainfall and growing degree days. The following is a list of the residue decomposition parameter: 1. Residue weight and harvest 2. Initial carbon-nitrogen ratio, and 3. Percent residue cover at harvest. The results are being used in the WEPP model to predict soil erosion. Data collection afor these parameters start 15 days after planting for vegetables and continue at 7 day intervals through maturity.

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Peat is used extensively in the nursery industry as a primary component in commercial “soilless” potting media. The increased use of peat as an organic amendment with superior water-holding capacity is challenged by economic and environmental pressures. Developing inexpensive and nutrient-rich organic media alternatives can potentially reduce fertilization rates, irrigation rates, and ultimately, nursery costs. In addition, controversy over the effects of peat mining has inspired a national search for peat substitutes. With our burgeoning population, it is logical to screen waste products as potential alternatives to peat. Growth of Pachystachys lutea Nees. (Golden Shrimp Plant) transplants was evaluated in media containing 0%, 25%, 50%, 75%, or 100% compost derived from biosolids and yard trimmings. Compost was amended with a commercial peat- or coir-based media. As compost composition in the peat or coir-based media increased from 0% to 100%, carbon/nitrogen (C/N) ratios decreased, and media stability, N mobilization, pH, and electrical conductivity (EC) increased. Bulk density, particle density, air-filled porosity, container capacity, and total porosity increased as more compost was added to either peat- or coir-based media. Plants grown in media with high volumes of compost (75 or 100%) had reduced leaf area and reduced shoot and root DW than the controls (no compost). Regardless of percentage of compost composition in either peat or coir-based media, all plants were considered marketable after 8 weeks.

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Popular press articles report that consumers often experience inconsistent results with retail potting media; however, few reports in the popular or scientific literature have quantified the variability in media properties. The purpose of this study was to assess the variability in physical and chemical properties among different brands of retail potting media and within certain brands. Twenty-four different packages of branded media, and multiple packages of five brands, were acquired from nine regional and national retail chain stores located in the Salt Lake City, Utah, area. Samples were analyzed for five physical and nine chemical properties. The coefficients of variation (cvs) among brands for initial gravimetric water content, bulk density, porosity, water retention, and air space were 85%, 74%, 21%, 59%, and 44%, respectively. The cvs among brands for saturated media (SM) pH, SM extract electrical conductivity (EC), nitrate-nitrogen (NO3-N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), total carbon (C), total nitrogen (N), and C:N ratio were 18%, 81%, 132%, 153%, 96%, 78%, 71%, 36%, 45%, and 49%, respectively. Only one of the 24 brands met all published standards for chemical properties of premium media. Thirteen of the brands did not meet standards for NO3-N; 12 did not meet standards for pH; and six did not meet standards for EC. There was more variation in physical and chemical properties among brands than within a brand of media. Label information describing media composition was not consistent with certain physical and chemical properties. No recommendations can be made which would allow consumers to select media that meets published standards. These results indicate better awareness of and/or adherence to standards is needed by the retail media industry to improve product quality and consistency.

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The ability of mycorrhizal and nonmycorrhizal `Elliott' highbush blueberry (Vaccinium corymbosum L.) plants to acquire soil N under different preplant organic soil amendment regimes (forest litter, rotted sawdust, or no amendment) was investigated in a field experiment using 15N labeled (NH4)2SO4. Plants inoculated with an ericoid mycorrhizal isolate, Oidiodendron maius Dalpé (UAMH 9263), had lower leaf 15N enrichment and higher leaf N contents than noninoculated plants but similar leaf N concentrations, indicating mycorrhizal plants absorbed more nonlabeled soil N than nonmycorrhizal plants. Mycorrhizal plants produced more plant dry weight (DW) and larger canopy volumes. The effect of preplant organic amendments on the growth of highbush blueberry plants was clearly demonstrated. Plants grown in soil amended with forest litter produced higher DW than those in either the rotted sawdust amendment or no amendment. Plants grown in soils amended preplant with sawdust, the current commercial recommendation, were the smallest. Differences in the carbon to nitrogen ratio were likely responsible for growth differences among plants treated with different soil amendments.

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temperatures, as noted in 2013, the plant shift from carbon gain to carbon loss is mainly due to a decrease in canopy Pn as temperatures increased above 24 °C. The ratio of R total to canopy Pn indicated high capacity for carbon gain (values of 1.2 to 1

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. Soluble solids at the L/F ratio of 20 and 10 were both 17.7 °Brix for the 0 g N but decreased to 15.9 and 16.3 °Brix for the 40 g N, respectively. Table 1. Effect of leaf/fruit ratios and nitrogen (N) rates on fruit characteristics of ‘Fuyu’ persimmon. z

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fertilizers provide nitrogen in one or both of these forms. The optimal NH 4 :NO 3 ratio depends on many factors, such as plant species, age of the plant, application timing, climate, and location ( Marschner, 2012 ). The responses of plant growth to N forms

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One-year-old grapevines (Vitis labrusca L. `Concord') were supplied twice weekly for 5 weeks with 0, 5, 10, 15, or 20 mm nitrogen (N) in a modified Hoagland's solution to generate a wide range of leaf N status. Both light-saturated CO2 assimilation at ambient CO2 and at saturating CO2 increased curvilinearly as leaf N increased. Although stomatal conductance showed a similar response to leaf N as CO2 assimilation, calculated intercellular CO2 concentrations decreased. On a leaf area basis, activities of key enzymes in the Calvin cycle, ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), NADP-glyceraldehyde-3-phosphate dehydrogenase (GAPDH), phosphoribulokinase (PRK), and key enzymes in sucrose and starch synthesis, fructose-1,6-bisphosphatase (FBPase), sucrose phosphate synthase (SPS), and ADP-glucose pyrophosphorylase (AGPase), increased linearly with increasing leaf N content. When expressed on a leaf N basis, activities of the Calvin cycle enzymes increased with increasing leaf N, whereas activities of FBPase, SPS, and AGPase did not show significant change. As leaf N increased, concentrations of glucose-6-phosphate (G6P), fructose-6-phosphate (F6P), and 3-phosphoglycerate (PGA) increased curvilinearly. The ratio of G6P/F6P remained unchanged over the leaf N range except for a significant drop at the lowest leaf N. Concentrations of glucose, fructose, and sucrose at dusk increased linearly with increasing leaf N, and there was no difference between predawn and dusk measurements. As leaf N increased, starch concentration increased linearly at dusk, but decreased linearly at predawn. The calculated carbon export from starch degradation during the night increased with increasing leaf N. These results showed that 1) grapes leaves accumulated less soluble carbohydrates under N-limitation; 2) the elevated starch level in low N leaves at predawn was the result of the reduced carbon export from starch degradation during the night; and 3) the reduced capacity of CO2 assimilation in low N leaves was caused by the coordinated decreases in the activities of key enzymes involved in CO2 assimilation as a result of direct N limitation, not by the indirect feedback repression of CO2 assimilation via sugar accumulation.

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determination of carbon, hydrogen, and nitrogen, automated method 5 6 Official methods of analysis of AOAC International. 18th ed. Gaithersburg, MD Gonçalves, A.C. Malico, I. Sousa, A.M.O. 2018 Solid biomass from forest trees to energy: A review

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renewable energy ( Hadrović et al., 2019 ). The element of biomass that largely determines the energy released during oxidation is carbon (C) ( Hartmann, 2014 ). The C content of biomass is usually 45% to 50% (by oven-dried mass) ( Schlesinger, 1991 ), but

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