JWSS - Journal of Water and Soil Science

---

In this study, the control method of greater wax moth using male sterilization technique with gamma ray and chemical control methods were examined and compared. In order to determine the safe and effective dosage of gamma-ray to sterilize male pupae of the greater wax moth, an experiment was conducted in a complete randomized design with 5 treatments and 3 replicates with 50 male pupae in each replicate. Treatments included different levels of gamma-ray dosages with zero, 250, 300, 350 and 400 gray.

Release ratio of sterile to normal males was also studied in a similar experiment. Treatments included sterile-males, normal males and virgin females with the ratios of 1:1:1, 2:1:1, 3:1:1, 4:1:1 and 5:1:1. In this study, male pupae were irradiated with 350 grays of gamma-ray. The possible parthenogenetic reproduction of this pest was also studied. In order to compare the results from the male-sterile technique and the chemical control of this pest, another experiment was conducted in wax stores using 3 treatments with 3 replicates. Phostoxin was used as the most common chemical pesticide with a dosage of 1 tablet of 3 grams of 56% per 1 m3 space for the control of this pest.

The results showed that the best dosage to sterilize male pupae of the greater wax moth was 350 grays of gamma-ray. Also the best release ratio was four sterile male, one normal male for each normal female (4:1:1). Our results indicated that the females of the greater wax moth were not able to reproduce through parthenogenesis. There was no significant difference between the chemical and male-sterile methods for the control of this pest.

---

The ability of earthworms in recycling a wide range of organic solid wastes is well established. Only a few earthworm species are suitable for commercial vermicomposting. Two species, Eisenia foetida and Lumbricus rubellus, are common in temperate regions. Samples of earthworms were collected from manure pills and forest litter in North and Northwest of Iran. The samples were maintained in pots under greenhouse conditions. External morphological characteristics of mature worms were used in identifying earthworm species. These characteristics included: total number of body segments, numbers of clitellum and tubercula pubertatis (TP) segments, dorsal and external body color, body size, prestomium and prostomium shape, number of first segment with dorsal pore and patterns of clitellum and TP. All collected samples belonged to the species Eisenia foetida. Under incubation conditions in manure substrate (a moisture of 70% saturation at 24±2^oC), each worm produced 1-2 cocoons daily and each cocoon contained 2-7 worm embryos. The collected earthworm samples showed a good ability in vermicomposting of manure, plant residues, and some organic industrial refuses. The C:N ratio decreased during the vermicomposting process, which indicates the improved stage of decomposition and the vermicompost stability.

---

Stabilizng sand dunes has been one of the main challenges in the arid regions. So far, different kinds of mulches have been used extensively for sand dune stabilization. This study was carried out to determine the optimum composition, concentration and thickness of clay mulch for sand dune stabilization. For this purpose two soil samples from clay flats of a playa with different amount of salinity from Ardestan area were used to make clay mulches. A sand dune sample was selected as bed for applying the mulch. To select the right ingredient and treatments, clay samples were mixed with sand and different amount of water, and sprayed on sand dune bed. In addition, wheat straw was added to some mixture to test its effect on stability of the mulch. Treatments with lowest crack and highest penetration of mulch in sand bed were selected for the experiment in this study. Mulch treatments contained (1): 250g sand dune + 250g clay + 25g straw (2) 250g clay + 25g straw (3) 250g sand + 250g clay (4) 250g clay (5) 125g sand + 125g clay and (6) 125g clay. All treatments were mixed with 500ml water. The experimental design was a CRD with a 6(mulch) * 2(thickness)* 2 EC factorial method with 3 replications. The results showed that clay mulch were resistant to wind erosion, but erosion took place when they had been bombarded with sandblast. The mulches with straw showed the highest resistance to erosion as compared to other treatments. With increasing the number of mulch layers, resistant to erosion also increased. The added stability of mulch was due to the increase in mulch thickness and also increases in clay and silt content. The overall result of this study shows that the mulch with two layers and higher mixture of clay and sands was the best treatment for the stabilization of sand dunes.

---

In tea plantation regions of northern part of the country, application of supplemental irrigation during dry periods (lacking rainfalls) in conjuction with proper nitrogen fertilizer application can significantly improve tea yield per unit of plantation area. In order to quantify the effectiveness of proper irrigation and nitrogen management on tea, the response of tea to various levels of irrigation and nitrogen applications was studied in Fouman suburb of Guilan province. Tea crop production function and its crop coefficient (K_C) were determined. A line source sprinkler irrigation was used for creatiating a variable irrigation application and a split-split-plot statistical design was used. Irrigation treatments consisted of full irrigation (I₄), deficit irrigation (I₃, I₂ and I₁) and no irrigation(I₀). Nitrogen application treatments were N₁, N₂ and N₃ (100, 180 and 360 kg/ha) in three replications randomly arranged as main plots, while irrigation treatments as sub plots were not randomized. During the growing period, soil moisture up to the depth of 90 cm was determined gravimetrically and actual crop water use was calculated from mass balance equation weekly. Reference evapotranspiration (ETo) was estimated by Penman-Montieth equation and was used to estimate tea crop coefficient. During growing period, the actual tea water use of I₄ and I₀ were computed to be 457 and 256 mm. Tea crop coefficient during dry period (June, July and Augest) ranged from 0.8 to 0.9. Crop resistance factor (K_y) for tea was found to be 1.37. Results indicated that optimum rate of nitrogen (180 kg/ha) along with supplemental irrigation, increased yield and water use efficiency (WUE). Futhermore, supplemental irrigation increased yield and WUE more than nitrogen application. In I₀ and I₁ treatments, application of 100 kg/ha nitrogen resulted the highest yield and WUE.

---

Composting and vermicomposting are two efficient methods to recycle organic wastes. In order to investigate the structural changes in organic matter during the composting and vermicomposting processes, cattle manure and filter-cake of sugar cane were incubated with and without earthworm's presence in a controlled temperature and moisture condition for 16 weeks. Compound samples were taken at 0, 8, and 16 weeks. Carbon, nitrogen and C:N ratio were measured by a CN analyzer apparatus. Solid samples were used for structural analysis using FTIR and solid state CP MAS 13C NMR devices. C:N ratio was decreased with improving decomposition process. The C:N ratio was slightly elevated after 16 weeks of vermicomposting. Structural analysis with both spectroscopic methods showed a decrease of O-alkyl C and increase of aromatic and carboxylic functional groups. The analysis of samples with 13C NMR showed that after 16 weeks, the percentage composition of O-alkyl filter-cake decreased from 41 percent in the first sample to about 33.1 percent. The amount of these compounds in manure samples decreased from 56.7 percent to 43.6 percent. Aromatic compounds in samples of raw filter-cake and manure increased from 12.5 and 13.5 percent to 16.4 and 18.7 percent, respectively. Percentage of carboxyl compounds increased, respectively, from 8.5 and 5.6 percent to 9.7 and 7.2% in the filter-cake and manure sample. Vermicomposts had higher content of aromatic groups compared to composts (In manure samples 18.7 instead of 17.1 percent). After 16 weeks of incubation the aromatic and carboxylic compounds slightly decreased in the vermicomposting process. Analysis of composts and vermicomposts with FTIR and 13C NMR resulted in similar signals with the different frequency intensities. There was a suitable correlation (r=0.897**) among the spectroscopic methods in characterization of composts and vermicomposts

---

Improper properties of sewage sludge include odors, trace elements concentration, and presence of pathogens limit its use in agriculture. Composting and using of earthworms in this process is one of the most suitable methods for stabilization and removal of unsuitable properties of sewage sludge. To investigate the effects of kind and mixing proportion of bulking material and sewage sludge decomposition stage on vermicompost quality, an experiment was carried out in a split plot design with three replications. In this experiment, the stage of sewage decomposition (raw sewage, digested sludge in digester, dewatered sludge in lagoons, and final dried sludge in lagoons) was main factor and kind of bulking materials (woodchips, three leaves, and wheat straw) and mixing proportion of bulking materials to swage sludge (0, 15, 30, and 45 %, V/V) were as subordinate factors. Chemical properties of sewage in different decomposition stages and bulking materials were determined. After 5 months of incubation in the controlled moisture and temperature condition, and in the presence of earthworms, the pot's contents were harvested, and nutrients and heavy metal concentration of vermicomposts were measured. Vermicomposts had relatively low pH and EC. Their nutrients content especially N, P, Fe, and Zn were high. These properties showed vermicompost suitability for use as a soil amendment and organic fertilizer. Heavy metals concentrations of vermicomposts, except for Zn, were lower than recommended values by EPA. Despite no significant difference between the kinds of bulking materials, mixing of these materials with sewage sludge decreased pH, N, and Pb content of produced vermicompost. According to the results, 30% (v/v) mixing of bulking material and sewage sludge is recommended

---

The soil pollution especially in urban soils is projected to increase drastically and its effects on chemical cycles are yet to be known. Approaches to measure air and water quality are well established, but urban soil quality assessment has received little attention. Soil quality assessment can help as a way to better understand the pollution increase outcomes in urban environments and to establish approaches and integrated soil quality assessment protocols in urban planning and landscape management. Considering lack of information in urban soil quality of Iran, the objective of this study was to assess soil quality under urban land use effect using minimum data set in western part of Tehran. In view of this, 56 soil samples were collected in three land use types of agricultural, parks and urban landscapes, and vacant urban lots and 12 physicochemical properties were measured. The results of analysis of variance (one-way ANOVA) showed that under influence of the land use types, organic carbon, total nitrogen, lime, bulk density and sodium have significant differences. The factor analysis was used to select minimum data set and the results showed that two factors with eigenvalues more than one, explaining more than 68% of total variance, have the most loading factors on organic carbon and sodium. Finally, soil quality indicator (SQI) was determined and compared in different land use types. The results showed that SQI has significant difference in urban land use types and the least soil quality is related to vacant urban lots.
 

---