JWSS - Journal of Water and Soil Science

The production of compost and vermicompost from manure and different organic residues and also, their enrichment with some fertilizers and other treatments have been extensively investigated. However, no study has yet been conducted on the enrichment of composted and vermicomposted manure with clay minerals. This research was, therefore, carried out to investigate the selected properties of phlogopite enriched manure during the composting process with and without earthworm activity. The experiment was conducted in plastic containers with the lid under an average temperature of 27.5°C and the humidity of 42.5% using a factorial arrangement in a completely randomized design with 3 replications. Factors included levels of phlogopite addition (0%, 20% and 40% by weight), with or without the earthworm Eisenia fetida for different time periods of 1.5, 3, 4.5 and 6 months. At the end of the experiment, the total of organic carbon, nitrogen, potassium, magnesium, and iron, as well as the contraction the available magnesium, potassium and iron, was determined. The results showed that the percent of organic carbon was decreased while the total nitrogen, the total and available potassium, iron and magnesium were increased with time. The results also indicated that a significant percentage of the total content of the elements in all treatments without phlogopite was available. However, in treatments containing phlogopite, the amount of the available elements was increased slowly with time. This was Due to the weathering of phlogopite mineral and the decomposition of manure. In general, it seems that the enrichment of composted and vermicomposed manure with phlogopite can guarantee the supply of nutrients such as potassium, iron and magnesium in a longer period, as compared with the ordinary composts.

Compost leachate is a liquid resulting from physical, chemical and biological decomposition of organic materials. The main objective of this study was to evaluate the influence of leachate compost on the physical, hydraulic and soil moisture characteristic curves. Also, the effect of leachate on the aerial organ fresh weight of corn was investigated. Leachate was added to clay loam and sandy clay loam soils at the rate of zero, 1.25 and 2.5 weight percent. The soil water characteristic curve and the estimation of the parameters of the van Gnuchten and Brooks and Corey models were performed using RETC software. Leachate increased the bulk density and decreased the available water of the clay loam soil. Only 1.25% of the leachate increased the available water in the sandy clay loam soil. Two levels of leachate decreased the bulk density of sandy clay loam soil. Leachate decreased the saturation hydraulic conductivity of the clay loam and increased this parameter of sandy clay loam soil. Leachate was more successful in increasing the aerial organ fresh weight of corn in the sandy clay loam soil. Therefore, leachate was more useful in sandy clay loam than in clay loam soil, and 1.25% treatment was better in the sandy clay loam soil. Also, the used leachate increased the repellency of both soils. Leachate caused the parameters of van Gnuchten and Brooks and Corey models to increase, as compared to the control in both soils.  

Due to the importance of nickel (Ni), and the effect of common soil additives on Ni fractions distribution, the present study was conducted to evaluate the effect of zeolite and vermicompost on nickel fractions over time. The experimental design consisted of a factorial combination of two levels of vermicompost (zero and 2% by weight), three levels of zeolite (zero, 4% by weight of Firoozkooh zeolite, and 4% by weight of Semnan zeolite), and two soil texture (clay and sandy loam) in a completely randomized design in triplicates. Treatments were contaminated with 50 and 100 mg nickel/kg soil. Ni fractions were extracted and measured at 20 and 60 days. The results showed that in initial soils, Car-Ni in sandy loam soil was higher than in clay soil, while the content of Fe, Mn- Ox Ni, OM-Ni, and Res-Ni in the clay soil was higher. In sandy loam soil, more nickel was recovered in Exch- and Car-fractions, while nickel recovery was higher in Mn, Fe-Ox Ni, OM-Ni, and Res-Ni in the clay texture. Zeolite addition caused a significant decrease of Exch- and Car-Ni in the clay soil on 60d and 100 mg/kg Ni level. Exch-Ni was reduced due to vermicompost application. Vermicompost application caused the decrease in Fe, Mn Ox-Ni in both studied soils and times, and OM-Ni increased by vermicompost application. Aging generally reduces the Exch-Ni but changes in Car-Ni over time depending on the soil texture. Aging did not affect Mn, Fe-Ox Ni, and Res-Ni, while OM-Ni increased over time in clay soil.