Purpose The disposal of solid waste is a serious environmental problem for humanity. Vermicomposting is used as one of the methods for recycling of organic waste, resulting in a humified material of great agronomic potential which promotes carbon sequestration when applied to the soil. The aim of this study was to evaluate the chemical characteristics of vermicomposts from cattle manure (CM), orange peel (OP) and filter cake (FC). Methods Three compost piles were set up, 2:1 OP ? CM, 3:1 FC ? CM and CM. The piles were initially composted for 60 days. Thereafter, earthworms were added to the piles to initiate the vermicomposting process. Results The pH and the organic carbon contents were above the minimum recommended values for organic fertilizers. The N content was below the minimum value but the C/N ratio was in the required range. The C/N values where lower in OP ? CM and FC ? CM than in CM. Further, the N contents of treatments were different with OP ? CM having the highest value. The C/N ratios of the piles were 9.52, 9.62 and 11.03 for OP ? CM, FC ? CM and CM, respectively, and were lower than the maximum recommended value by the Ministry of Agriculture, Livestock and Food (Ministry of Agriculture 2009). Conclusion Thus, co-vermicomposting of filter cake and orange peel with cattle manure has the potential for application sustainable agriculture.

Organic dryland wheat (Triticum aestivum L.) is an important crop in Utah and the intermountain western United States; however, growers face numerous challenges maintaining yield, grain quality, soil fertility, and health. Wheat yields in the West are severely constrained by lack of rainfall, so dryland organic wheat farmers generally do not grow cover crops due to the risk of subsequent crop failure or apply soil amendments due to the inability to recoup application costs in the short term. Compost may have significant non‐nutritive as well as nutritive effects on soil processes, however, potentially changing calculations of perceived costs vs. benefits. The goal of this study was to quantify the effects of a one‐time compost application on soil health, yield, and crop quality in an organic dryland wheat–fallow system in northern Utah. Four rates of compost, applied once, (0, 12.5, 25, and 50 Mg ha−1 dry weight, DW) were compared to anhydrous ammonia (50 kg N ha−1) applied at planting. Mineralizable C, microbial biomass, and phosphatase enzyme activity increased significantly at all compost rates, while available soil P increased at the 25 and 50 Mg ha−1 rates and total soil N at the 50 Mg ha rate−1. Soil moisture was generally no different between treatments. Wheat yield was significantly greater 3 yr after application at the 50 Mg ha−1 compost rate only, with no response to conventional fertilizer. A lack of yield response to conventional fertilizer suggests that non‐nutritive benefits of improved soil health were responsible for improved yields at the high compost rate.

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With the expanding hemp cannabidiol (CBD) industry in the United States, information on fertilizer recommendations for optimal production under field conditions is deficient in the literature. This study evaluates the effects of nitrogen (N) fertilization on bud biomass and CBD yield of two high-yielding CBD hemp varieties (Spectrum and Therapy) under field conditions. Four application rates of N fertilization (0, 56, 112, and 224 kg N ha−1) were supplied using 2 commercially available N fertilizers. Fresh bud biomass, dry bud biomass, and CBD yield (g plant−1) increased quadratically with N fertilization rates, with optimum rates between 140 and 190 kg N ha−1. When pooled across varieties, the tissue N concentration was linearly related to the fresh bud biomass, dry bud biomass, and CBD yield. Our findings show that N fertilization can affect CBD yield under field conditions. The resulting effect of N fertilizer rates on these varieties could serve as a preliminary guide for CBD hemp production under field conditions, although results may differ with variety, location, or fertilizer type.

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Application of crop residues and biochar have been demonstrated to improve soil biological and chemical properties in agroecosystems. However, the integrated effect of organic amendments and hydrological cycles on soil health indicators are not well understood. In this study, we quantified the impact of hemp residue (HR), hemp biochar (HB), and hardwood biochar (HA) on five hydrolytic enzymes, soil microbial phospholipid (PLFA) community structure, pH, permanganate oxidizable carbon (POXC) soil organic carbon (SOC), and total nitrogen (TN). We compared two soil types, Piedmont and Coastal Plain soils of North Carolina, under (i) a 30-d moisture cycle maintained at 60% water-filled pore space (WFPS) (D-W1), followed by (ii) a 7-day alternate dry-wet cycle for 42 days (D-W2), or (iii) maintained at 60% WFPS for 42 days (D-W3) during an aerobic laboratory incubation. Results showed that HR and HB significantly increased the geometric mean enzyme activity by 1-2-fold in the Piedmont soil under the three moisture cycles and about 1.5-fold under D-W in the Coastal soil. In the presence of HA, the measured soil enzyme activities were significantly lower than control under the moisture cycles in both soil types. The shift in microbial community structure was distinct in the Coastal soil but not in the Piedmont soil. Under D-W2, HR and HB significantly increased POXC (600–700 mg POXC kg-1 soil) in the Coastal soil but not in the Piedmont soil while HA increased nitrate (8 mg kg-1) retention in the Coastal soil. The differences in amendment effect on pH SOC, TN, POXC, and nitrate were less distinct in the fine-textured Piedmont soil than the coarse-textured Coastal soil. Overall, the results indicate that, unlike HA, HR and HB will have beneficial effects on soil health and productivity, therefore potentially improving soil’s resilience to changing climate.

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Prolonged benefits following a single application of compost in organic dryland wheat (Triticum aestivum L.) in the western United States have been documented, including the long-term bioavailability of phosphorus (P). Information on the bioavailability and forms of P following a one-time compost application in marginal organic agroecosystems with low and infrequent use of fertilizers is required to promote sustainability. The goal of this study was to evaluate changes in Hedley P pools following a one-time application of manure compost and its potential influence on short-term (3-yr) P bioavailability. Steer manure compost at 0, 25, and 50 Mg dry weight ha -1 was applied to two organic dryland sites, Snowville and Blue Creek, with contrasting soil characteristics in northern Utah in a randomized complete block design. Potential phosphatase assays, a laboratory aerobic incubation study, and soil P fractionations were carried out to assess the transformation of P 1 and 3 yr after a one-time compost application. At 0-10 cm, compost application resulted in increased acid phosphatase at Snowville (67.3 vs. 42.7 μg p-nitrophenol g -1 soil, p = .003), while alkaline phosphatase increased at Blue Creek (124 vs. 49 μg p-nitrophenol g -1 soil, p = .0185). The path coefficient between compost P and Hedley labile inorganic P was significant at Snowville, but not at Blue Creek, suggesting that the pathways of P differed between the sites. The Hedley stable P pool was a sink of compost P at Snowville but a source at Blue Creek. In conclusion, our work shows that a one-time compost application had a differential effect on the variation in P dynamics in organic dryland winter wheat-fallow soils. The potential long-term benefits may be greater in semiarid soils with lower available P levels, higher carbonate levels and pH, and drier conditions.