JWSS - Journal of Water and Soil Science

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Tillage systems and organic manures could affect soil physical and mechanical properties. This study was conducted to investigate the impacts of two tillage systems including conventional tillage by moldboard plowing (plowing depth, 30 cm) and reduced tillage by disk plow (plowing depth, 15 cm) and three rates (0, 30 and 60 ton ha-1) of farmyard manure (FYM) on the soil penetration resistance under corn cropping in a split block design with 3 replications. The cone index (CI) decreased with increase of the tillage depth. It is attributable to soil disturbing and loosening of the deeper layers under conventional tillage compared to reduced tillage. This trend, however, was observed only in the first (after treatments’ application and before cropping) and second (the highest rate of vegetative growth) samplings. In the third sampling (after harvest), there were not significant differences between the CI values under two tillage systems in different soil depths. It might be due to soil re-compaction (approaching the pre-tillage state) as well as disappearance of the tillage effects seven month after commencement of the experiment. In fact, the soil mechanical resistance increased with the time indicating soil re-compaction over the growing season. Adding FYM to the surface layer (i.e. 0-10 cm) of ridge soil resulted in significant decrease of soil mechanical resistance compared to control treatment. The CI decreased significantly in the 30 ton ha-1 treatment up to the stage of highest rate of vegetative grow, but the effect on CI was diminished after harvest. However, the decreasing effects of the 60 ton ha-1 treatment on the CI continued to the harvesting time. There were no significant effects of FYM in the soil deeper than 10 cm from the ridge surface and in all of the layers in furrow. The CI did not decrease significantly in the furrow due to negligible effect of manure application for the inter-row position.

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One important parameter in determining the allowable stress to prevent soil compaction is pre‌compaction stress (σpc). If the stress induced into the soil due to agricultural machinery traffic is lower than the σpc, the possibility of the irreversible (plastic) deformation is low. In this study, plate sinkage test (PST) and confined compression test (CCT) were used to determine the σpc of the disturbed soil samples obtained from the topsoil of a long-term organic amendment experiment. In the organic amendment experiment, organic manures (sewage sludgeو compost, farmyard manure) at three rates (25, 50 and 100 t ha-1) and one inorganic fertilizer combination (250 kg urea ha-1 and 250 kg ammonium phosphate ha-1) were added to a silty clay loam soil for seven years under wheat-corn rotation. The effect of organic and inorganic fertilizers and gravimetrical water contents (17.1 and 20.9% db) on the σpc values was determined using two statistical designs: 1) factorial design and 2) orthogonal contrasts in a completely randomized design with three replications. The σpc values were estimated by the following methods: 1) Casagrande, 2) maximum curvature and 3) intercept of virgin compression line (VCL) with the x-axis at zero strain. The results showed that in both tests, the σpc values for treatments amended with organic manures had over-estimations and the values of the over-estimation were increased as the manure application rate increased. The values of the over-estimations for CCT were higher than for PST. Therefore, it can be concluded that the results of the PST are more reliable. The σpc values estimated by any of the three procedures depend on the manure treatment as well as the initial water content of the soil. For determining the stress at the threshold of the compaction for the un-manure soils (control and inorganic fertilizer) or the treatments amended with low application rate (25 t ha-1) of the organic manures, the PST and the Casagrande procedure can be recommended. In contrast, for the soils amended with high application rates (50 and 100 t ha-1), the PST and the maximum curvature procedure can be used.

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Soil structure and aggregate stability affect soil erodibility. There is a necessity for increasing aggregate stability against erosive factors such as wind and water. This study was conducted on surface soil samples (0-20cm) collected from agricultural land susceptible to erosion located in Chahoo, southeast of Fars province. The experimental design was CRD with 10 treatments and was replicated 3 times as follows: control plot (without addition of soil amendments), pure gypsum, chopped wheat straw, farm yard manure, gypsum+wheat straw, gypsum+ farm yard manure (1% w/w), cement at levels (0.3% w/w), (0.6% w/w), (0.9% w/w), gypsum +cement (0.9% w/w). After one, four and seven months, the amounts of soil aggregates in 53-4000 µm sizes were determined by wet sieving and MWD was calculated. The results of aggregate size distribution in every stage of the experiment showed that application of farm yard manure and wheat straw separately or in combination with gypsum through reduction in aggregates with diameters of <106 µm has caused an increase in aggregates with diameter of >106 µm. Based on the results of this research, the effect of these treatments, which increased MWD of the aggregate, results from the amount of aggregates with diameters larger than 1000 µm. According to the results of this study, it is suggested that these treatments be considered suitable to increase the stability of sensitive silt loam soils.

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The effects of waterlogging, sewage sludge and manure on the Fe, Mn, Zn, Cu, Pb and Cd uptake and concentrations in roots and shoots of sunflower (Helianthus annuus L.) were investigated in greenhouse conditions. A factorial experiment based on a completely randomized design with three replications including duration of waterlogging at five levels (0, 2, 4, 8, 22 days) and source and amount of organic fertilizer at five levels (0, 15 and 30 grams of both manure and sewage sludge per kg of soil) was conducted. The results showed that by increasing the duration of waterlogging, the Mn uptake and concentration in shoots and Mn concentration in roots increased but Mn uptake in roots did not change significantly. The uptake and concentration of Fe in shoots and Cd concentration in shoots and roots initially increased and then decreased after soil waterlogging, while Zn and Cu concentration of roots increased after an initial decrease. The effect of soil waterlogging on the Pb, Cu and Zn concentrations in shoots was not significant. By application of sewage sludge and manure the uptake and concentration of Fe, Mn, and Zn in shoots and Cu uptake in shoots increased but the uptake and concentration of Pb in shoots increased only by application of sewage sludge. The effect of source and amount of organic fertilizer on the Cd uptake and concentration in shoots, Cd concentration in roots and Cu concentration in shoots was not significant. By application of sewage sludge the root concentration of Fe, Mn, Cu and Zn increased but root concentration of Cd and Pb did not change significantly. The maximum uptake of heavy metals in shoots was obtained by application of 30 g sewage sludge/kg of soil. The effect of soil waterlogging on the heavy metals uptake and concentrations in the roots and shoots was dependent on the source and amount of organic fertilizer. Sunflower plant accumulated Fe, Mn, Zn, Cu, and Pb in roots while the Cd concentration in roots did not differ with shoots significantly.

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In agriculture, cow manures are used to enhance soil fertility and productivity. Escherichia coli is the most common fecal coliform in cow manure and considered as an index for microbial contamination of groundwater resources. The objective of this study was to investigate the transport of Escherichia coli (released from cow manure) through the field soil. Lysimeters (with internal diameter of 20.5 and height of 50 cm) were inserted into an in situ clay loam soil. Unsaturated soil water flow was controlled at an inlet matric potential of –5 cm using a tension infiltrometer. When the steady-state flow was established, air-dried fresh cow manure was applied on the lysimeters at a rate of 10 Mg ha-1 (dry basis) and the soil-manure leaching started. Soil solution was sampled at 1, 2, 4, 6, 12 and 24 h after leaching initiation using plastic samplers installed at depths of 20 and 40 cm. Concentrations of Escherichia coli in the soil solution (C) and the influent (C0) were measured using the plate count method. Impacts of soil depth, sampling time, and their interaction on C and C/C0 were significant (P<0.01). In all leaching times, relative adsorption index (SR) was lower when both soil layers were considered and the filtration increased with soil depth. When the concentration was corrected for the second layer (i.e. 20–40 cm), the SR values in this layer were considerable and greater than those in the first layer at 4 and 6 h. The influence of surface layer was substantial in bacterial filtration however, the preferential flows especially in the initial leaching times resulted in bacterial movement towards the second layer. Temperature drop reduced bacteria release from the manure, increased viscosity of the flowing water, and consequently diminished significantly the bacteria concentration in the soil solution at 24 h. Overall, it was found that similar to surface layer, subsurface layer might have great role in bacterial filtration due to its higher clay and carbonate contents

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Cow manure and sewage sludge add heavy metals to soil. Organic and inorganic fractions in these compounds can immobilize heavy metals such as lead (Pb) and affect their bio-availability. This investigation was conducted to compare the effects of organic and inorganic fractions of sewage sludge and cow manure on distribution of lead chemical forms in soil as a completely randomized design. Treatments consisted of application of 10% (w/w) enriched sewage sludge and cow manure (6 g Pb kg-1 organic amendments). Another treatment was also used in which soil Pb concentration was increased to 600 mg kg-1 soil using Pb(NO3)2 salt. To compare the effects of organic and inorganic fractions, organic carbon, iron oxide and easily reducible iron and manganese were removed from cow manure and sewage sludge, and were added to the soil by 10% (w/w). The samples were incubated at 23-25ºC for 111 days and their moisture was maintained at 80% water field capacity. More than 50% Pb in Pb(NO3)2 treatment was in exchangeable fraction, while for cow manure and sewage sludge treatments more than 40% Pb was found to be in oxide fraction. Application of cow manure and sewage sludge increased the Pb in oxide fraction by 14.8 and 17.5%, respectively. Removing organic carbon fraction of cow manure and sewage sludge increased the Pb bound to residual fraction by 12% and 14% respectively. Removing iron oxide fraction of sewage sludge and cow manure decreased the Pb bound to oxide fraction by 8% and 13%, respectively. Removing easily reducible iron and manganese decreased the oxide fraction of Pb by 16% and 14%, respectively. It is concluded that, despite relatively high amounts of organic carbon in the sludge and manure, inorganic fractions of these materials have more significant effects on availability of Pb in soil.

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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

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The incorporation of plant residues in soils of arid and semiarid regions is a major principle of sustainable agriculture. This study was conducted at the research farm of Urmia University (37° 32’N and 45° 5’ E), Urmia, Iran during the 2009 and 2010 growing seasons. Five green manure crops were grown in four replications arranged in a randomized complete block design. The treatments included white clover (T.repens), sainfoin (Onobrychis viciaefolia), pearl millet (Panicum miliaceum), sorghum (Sorghum bicolor) and turnip (Eruca sativa). Changes in soil nutrient elements and nitrogen mineralization were measured during different time periods after plant residues incorporation to soil. The plants were irrigated 50% of field capacity during growing period. The results showed that the total nitrogen and NH4-N were influenced by type of green manure in both years. The lignin and cellulose were the main factors controlling N mineralization and residue decomposition. In the first and second year, the results indicated that pearl millet green residues resulted in the highest amount of soil organic carbon. Nitrate-N content reached the highest amount in sainfoin and white clover. In conclusion, white clover and sainfoin due to increasing total and mineral nitrogen for subsequent plants could be introduced as a proper green manure in water deficit conditions.

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  Many studies have been carried out on pure minerals to study the effect of plant roots on minerals weathering, but information on mineral weathering that normally occurs in different soil fractions is limited. To investigate the effect of

German Chamomile (Matricaria chamomilla L.) cultivation on mineral weathering of clay and silt fractions in five different soil series amended or not amended (control) with cattle manure, a factorial experiment was performed in a randomized complete block design (RCBD) with three replications. At harvest time, rhizosphere soil was separated and mineralogical studies were performed through X-ray diffraction (XRD) and compared to before cultivation Results showed that in clay sized particles, trioctahedral chlorite transformed to di-octahedral chlorite while kaolinite disappeared. In silt sized particles, feldspar transformed to amphibole and vice versa The pots amended with manure showed the same changes for clay and silt sized particles as the pots without manure.

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Management of organic and inorganic treatments may have positive or negative effects on soil quality, plant growth and human nutrition. The objectives of this study were to determine the effects of organic and inorganic zinc fertilizer application on soil quality indicators and wheat yield. This research was conducted at Agricultural Research Station Roudasht, Isfahan, Iran. Sewage sludge and cow manure (5 and 10 t/ha), ash rubber (1 t/ha), powder rubber (200 kg/ha), ZnSO4 (40 kg/ha) were applied and wheat was cultivated. Soil samples were collected at tilling and harvest stages. After taking samples and measurements of the soil parameters, we determined the critical limits for each category and class rating for the each soil parameters, and the soil quality index was calculated. The results showed sewage sludge and rubber ash were significantly effective in increasing soil bioavailable Zn compared to other treatments. Application of sewage sludge and cow manure at 10 ton/ha improved soil quality. The expanded soil quality index can help better understand the effect of fertilizers on soil. A positive and significant relationship between soil quality indicators and Zn uptake and wheat yields was also observed. Our results indicate that addition of 10 t/ha sewage sludge as fertilizer can significantly improve soil quality, supplying the necessary amount of Zn for wheat growth.

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This study was conducted to investigate the effects of poultry manure (PM) and its derived biochars on chemical properties of a sample calcareous soil. Poultry manure and its derived biochars at 200(B₂₀₀), 300(B₃₀₀) and 400(_B400)°C were incorporated with 400 g of soil at 2% level (w/w) and incubated for 150 days. Some chemical properties of soil and bio-availability of some nutritional ingredients such as phosphorous, potassium, iron, manganese, zinc and copper were determined at different times of incubation. Soil nutrients availability, organic carbon (OC), electrical conductivity (EC) and cation exchange capacity (CEC) increased by addition of all these organic substances. Biochars prepared at higher temperatures were more effective in increasing soil OC and its durability. Addition of PM and B₂₀₀ decreased soil pH, whereas B₄₀₀ increased it. Although highest soil EC was observed in B₃₀₀ and B₄₀₀ treated samples in the early stages of incubation, the rate of increasing in soil EC was higher at PM and B₂₀₀ treated samples. In general, it was concluded that biochar prepared at 300°C had the highest effect on availability of nutrients and their durability in the soil. 

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This study was conducted to investigate the effects of poultry manure (PM) and derived biochars on phosphorous (P) availability and apparent recovery in a calcareous soil. Treatments consisted of four rates of P (0, 30, 60 and 90 µgg-1) and five organic substances (blank, poultry manure and derived biochars at 200, 300 and 400°C). organic substances were incorporated with 400 g of soil at 2% level (w/w). All soil treated samples plus control were incubated for 150 days. Soil P availbility determined at 8 different stage of incubation time period. Phosphorous availability was less in untreated soil samples with organic substances and also decreased with time. Although P recovery from inorganic P fertilizer was high in the early stages of incubation time compared to treated soil samples but decreased with time, if not treated with organic substances. Phosphorus availability and recovery increased with time in PM and biochares treated soil samples. Simultanous application of inorganic P and organic substances decreased apparent P recovery. Negative interaction obsorved between organic substances and high rates of inorganic P fertilizer on P availability. It was concluded that PM biochar prepared at 300°C had the highest effect on adjusting P availability in calcareous soil.

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To determine the nitrate pollution (water, soil, and tubers) in small (< 0.5 ha), medium (0.5- 1 ha) and large (> 1 ha) size of potato fields, this study was conducted in Fereidan region of Isfahan province during growing season of 2014-2015. For this purpose, the amounts of inputs and the tuber yield were recorded in each farm. Also, average nitrate-N concentration in irrigation water, soil and tubers of different potato farms were measured before planting and after harvesting. The results showed that the average soil N-nitrate concentration in small, medium and large size farms were 16.3, 17.4 and 19.9 mg kg^-1 before planting and 10.3, 13.3 and 23.3 mg kg^-1 after harvesting, respectively. The average N-nitrate concentration of irrigation water in small, medium and large size farms were 36.3, 27.1 and 19.5 mg L^-1 before planting and 47.6, 33.1 and 16.4 mg L^-1 after harvesting, respectively. At the post-harvest time, NO₃-N concentration of irrigation water were below the standard range concentration (45 mg L^-1) in the all large farms while 87 % of small and 85% of medium farms had more than standard concentration. The nitrate concentrations of tubers in large-sized farms were lower than others. The tuber NO₃-N concentration was affected by potato cultivar. The lowest concentration of nitrate was observed in the late-season potato cultivars (Agria). that might be associated with greater tubers yield.

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In order to investigate the persistence of organic amendments, nitrogen and zinc effects on soil characteristics in rapeseed-wheat rotation, a factor analysis was conducted in a complete random design with three replications in two consecutive years in a greenhouse. Treatments in the first year consisted of N fertilizer, municipal waste compost, vermicompost, sheep manure. The control consisted of zinc and two rapeseed cultivars. In the second year of the experiment, two cultivars of durum wheat were sown in the same pots as the first year of the experiment. Results showed that two years after application of cattle manure, a significant increase in soil electrical conductivity (41.81 %), available K (59.45 %) and available Mn (79.82 %) compared to the control were found.  Saturated soil moisture (48.57%), total N (94.66 %), available Fe (46.49 %) and available Cu (47.51 %) significantly increased by municipal waste compost compared to the control. Also, Zinc had a significant effect on soil total N (0.28 %), available K (218.4 mg/kg) and available Mn (12.89 mg/kg). Generally, the results showed that application of organic amendments can change many soil characteristics which some of their impacts might last for next upcoming years. Therefore, it is necessary to monitor the soil characteristics and nutrients availability of the fields that were treated with organic amendments in the years after application.
 

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In line with sustainable agriculture development, an experiment was conducted including tillage as the main factor in two conventional systems (plowing and mixing fertilizer with soil) and no tillage (leaving residuals of green manure and direct corn sowing). The fertilizer resources were T0: control, T1: barley green manure without chemical and manure fertilizers, T2: barley green manure with full use of the recommended chemical fertilizer (NPK) to barley containing urea, super triple phosphate and potassium sulphate respectively as 165, 90, and 75 kg/ ha, T3: green manure with two -third residual of chemical fertilizer for barley and a third of the residual to corn, T4: green manure with one- third chemical fertilizer for barley and two-third for corn, T5: barley green manure mixed with 50% manure and 50% chemical fertilizer, and T6: green manure with 40 tons of manure used as a sub-plot in the split plot and in completely random blocks with three replications for two crop years ( 2013-2014) at the Agricultural Research Station, Sistan. The results showed that in comparison with no-tillage, the conventional tillage resulted in a significant increase in grain yield, the contents of nitrogen, phosphorus, potassium and soil organic carbon, bulk density and moisture content of the soil decreased in the conventional tillage. Sources of fertilizer (organic and chemical fertilizers) significantly increased soil organic carbon, nitrogen, phosphorus, potassium, and soil moisture content. The pH and soil bulk density factors decreased after using manure sources. Interaction tillage in the fertilizer sources showed that in the conventional tillage and Treatment T5 (mixture of manure, green and chemical fertilizers) the highest yield of corn was obtained with an average of 8471 kg/ha. The results of this experiment reported that using conventional tillage system with mixture of 50% manure, green and chemical fertilizers can increase corn grain yield, provide the dynamics of nitrogen, phosphorus, potassium, organic carbon, and improve soil bulk density and soil pH.
 

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