used in greenhouse studies are typically grown in sand to determine phytotoxicity of herbicides in the absence of soil carbon, whereas most field soils where turfgrasses are grown contain carbon, which can bind with topramezone. The soil adsorption
low-quality soils on urban landscapes, contribute to increased concentrations of soil organic carbon (SOC) within amended depths ( Hansen et al., 2007 ; Vietor et al., 2007 ; Wright et al., 2005 ). Increased SOC enhances water infiltration and soil
water. Carbon. The importance of examining leachate DOC is to quantify losses of soil carbon that might otherwise contribute to soil carbon sequestration. Furthermore, humic acids leaching to groundwater aquifers have the potential to form
. Sampling and analysis. Carbon mineralization, C pool differentiation, and soil biological responses were analyzed for CON, BG, and BSM and the medium compost rates of CLT, WC, LC, and NLC only to focus on groundcover management affects. Soil N supply, total
. 2010 and again on Oct. 26, 2011, whereas all other plots remained fallow during the fall and winter of both seasons. Table 1. Cover crop and soil amendments by treatment. Table 2. Total biomass, carbon (TC) and nitrogen (TN) content, and C:N ratio of
orchards, depending on the climatic and soil characteristics of the region (Triplett et al. 2008). Soil carbon (C) and nitrogen (N) inputs for orchards are thought to originate from plant litter (e.g., leaf litter, mowing), below-ground residues (e.g., dead
result of the imposed treatments. Fig. 1. Groundcover management system [i.e., shredded paper (SP), wood chips (WC), mow-blow (MB), and green compost (GC)] effects on soil organic matter (SOM), total soil carbon (TC), and nitrogen (TN) concentrations, TC
Soluble nitrogen (ammonium and nitrate) is released when soil organic matter is mineralized. The amount of N released by this process depends on the amount of organic matter present and soil temperature. Cranberry (Vaccinium macrocarpon Ait.) grows in acidic soils with a wide range in organic matter content. To evaluate how soil N release is affected by soil temperature, intact soil cores were collected from sites that had received no fertilizer and placed in PVC columns. Four different soil types, representing the range of cranberry soils (sand, sanded organic soil, peat, and muck), were used. Each column was incubated sequentially at six different temperatures from 10 to 24 °C (2.8 °C temperature intervals) for 3 weeks at each temperature, with the soils leached twice weekly to determine the amount of N release. The total amount of N in leachate was highest in organic soils, intermediate in the sanded organic soil, and lowest in the sands. The degree of decomposition in the organic soils was important in determining which form of N predominated. In the more highly decomposed organic soil (muck), most of the N was converted to nitrate. The data from this study resulted in the development of two models—one predicting the N mineralization and the other predicting the proportion of N in each of the two forms. Key factors for N release rate were soil temperature, percentage of clay, and organic carbon content. For predicting the proportion of N as ammonium vs. nitrate, key factors were soil temperature, soil pH, and the distribution of mineral matter in the silt and sand fractions.
the compost C:N ratio was 11. Table 1. Hairy vetch and compost biomass, carbon and nitrogen applied to the soil in 2016 and 2017. Soil inorganic N, and nitrate concentration in leaf petiole sap. The effect of hairy vetch and compost on soil inorganic N
The effects of repeated application of two composts differing in carbon: nitrogen (C: N) ratio on soil NO3-N, soil NH4-N, and leaf lettuce yield was studied over three sequential crop cycles from 1995 to 1996. One compost type (HiCN) was prepared primarily from yard wastes and had a C: N ratio of 29 to 32:1 The other compost (LoCN) was a compost composed of a mixture of crude materials including yard wastes, feedlot manures, and vegetable trimmings and had a C: N ratio of 10 to 12:1. Before transplanting leaf lettuce, both composts were applied and incorporated in the same plots repeatedly over three crop cycles at rates of 9, 18, 36, and 54 Mg·ha–1 (dry mass) in each application. In the first crop cycle, no differences were observed for weekly soil NO3-N, NH4-N, or leaf lettuce yield among compost types or rates. In the second and third crop cycles, weekly soil NO3-N and soil NH4-N were directly related to LoCN compost application rates. First harvest lettuce yield was also directly related to LoCN rate in the second and third cycles, but total yield was not related to LoCN rate. In the second and third cycles, soil NO3-N and early and total lettuce yield were inversely related to rate of application of the HiCN material. Weekly soil NH4–N was not consistently related to application rates of HiCN or LoCN material.