Iranian Journal of Soil Research
Year:2019 | Volume:32 | Issue:4 |Papers Count:11

This research aimed to investigate the effects of minimum and conventional tillage systems on nitrogen and water consumption of wheat. By using a splitblock design and implementing two single line-source sprinkler systems, effects of four levels of 0, 90, 135, and 180 kgN. ha-1 from urea source and four levels of irrigation water (4610, 4240, 3850 and 3395 m3. ha-1) was studied under conventional and minimum tillage systems, . The results showed that, in both tillage systems, by reducing water consumption, the number of spikes. m-1, grain yield, and wheat nitrogen uptake decreased significantly. In conventional tillage system, grain yield, grain yield components, and nitrogen uptake increased by nitrogen application until 180 kgN. ha-1 levels; but in minimum tillage system, these parameters increased until 135 kgN. ha-1 and decreased at 180 kg N. ha-1 level. The results showed that values of the studied parameters in conventional system were higher than the minimum tillage system, but, except the number of spiklet. m-2 and amounts of grain protein, there were no differences between the two tillage systems. The results also showed that, in both tillage systems, the highest water use efficiency (WUE, 1. 85 kg. m-3) was obtained from combined application of 135 kgN. ha-1 and 6700 m3. ha-1 irrigation water. However, the highest grain yield in conventional tillage system (8226 kg. ha-1) was obtained from combined application of 4610 m3. ha-1 of water and 180 kg. ha-1 nitrogen, with WUE of 1. 85 kg. m-3. In minimum tillage system, the highest grain yield (8378 kg. ha-1) was obtained from combined application of 3850 m3. ha-1 of irrigation water and 135 kg. ha-1 nitrogen, with WUE of 1. 79 kg. m-3. In other words, in the minimum tillage system, by using less water and nitrogen, a yield similar to the conventional tillage was obtained.

This research was conducted to investigate the response of autumn-planted sugar beet varieties to nitrogen and parameters of its efficiency. The experiment was arranged as factorial in a randomized complete block design with three replications. The first factor consisted of four nitrogen levels (control" without nitrogen application"), 30% less than optimum level, optimum level "on the basis of optimum level soil residue nitrate", and 30% more than optimum level). The second factor consisted of three varieties (Rasoul" as regional control", Sharif "SBSI001", and Palma). The result of combined analysis showed that nitrogen application on root yield, sugar content, and other root quality traits (white sugar, molasses content) was significant. Moreover, with higher use of nitrogen, sugar yield decreased, but other quality indices (Na, K, etc) increased. The effect of variety on the traits studied was significant including root and white sugar yields. Palma variety had the highest root yield and white sugar yield compared to other varieties. Also, with more nitrogen application, efficiency parameters (use, utilization and uptake) decreased. The interaction of treatments was significant on the traits such as sugar percentage, white sugar percentage, and molasses sugar content, such that Palma variety was better in terms of the above indicators. The interaction of treatments was not significant on efficiency indices, but Palma cultivar, compared to other varieties, had the highest use and utilization efficiency. Therefore, to achieve economic yield of white sugar in this region and for conditions similar to this experiment, application of nitrogen at 30% less than the optimum rate and use of plma variety is recommended followed by Sharif and Rasoul varieties.

Water infiltration process into the soil is significantly affected by plant residue management and tillage systems, which are important factors for designing efficient irrigation systems, especially in arid and semi-arid regions. We aimed to estimate the coefficients of infiltration process models (including Kostiakov-Lewis, Kostiakov, Horton, SCS and Philip) and their performance under the effect of residue management (residue removal and retention) and different tillage systems (conventional tillage, reduced tillage, and no-tillage). The field experiment was conducted in wheat (Triticum aestivum L. )-corn (Zea mays L. ) rotation based on split-plot design with three replications, in Zarghan, Fars province, during 2016 and 2017. The water infiltration process was determined by double ring method in three replications for each crop. Then, the statistical criteria of determination coefficient (R2), root mean square error (RMSE), and efficiency model (EF) were defined by Solver tools and used to quantify and classify the infiltration process models. In wheat cultivation and residue removal, the highest performance for estimating of water infiltration was obtained by Kostiakov-Lewis model under conventional tillage (R2, RMSE, EF were 0. 99, 0. 07 and 99. 99%, respectively). In the case of reduced tillage, R2, RMSE, EF were 0. 99, 0. 13, and 99. 99%, respectively), while Horton’ s model in corn cultivation and residue retention was the best model under no-tillage system (R2, RMSE, EF were 0. 99, 0. 14 and 99. 70%, respectively). Among tillage systems, the lowest performance of models was observed for SCS, Kostiakov, and Philip models in a wheat-corn-wheat rotation. Overall, to quantifying water infiltration process into the soil under arid and semi-arid region such as Zarghan, it is recommendable to apply Kostiakov-Lewis and Horton models in, respectively, wheat and corn fields.

Nitrate is an important pollutant that accumulates in edible parts of crops. This accumulation usually occurs because of misuse and excess use of N-fertilizers. Nitrate is transformed to nitrite and then to nitrosamine, which is a carcinogen compound, in digestion system of human and animal bodies. Potato is the third important foodstuff in Iranian food basket after wheat and rice. Therefore, it seems that evaluating the nitrate pollution in potato and recognition of the pollution sources and ways to reduce the pollution is necessary. Potato tuber samples were collected from the main Fruit and Vegetables Supply Center of Tehran once a week, from May 2008 to May 2009. Additionally, potato samples were collected directly from different farms in 9 most important potato-producing regions, namely, Esfahan, Charmahal, Hamadan, East-Azarbaijan, Ardabil, Tehran, Khozestan, Fars, and Kerman (Jiroft and Kahnooj). Nitrate content in edible part and water content of fresh potato tubers were determined in all 341 samples in the central laboratory of Soil and Water Research Institute of Iran. Results showed that nitrate content in potato tubers ranged from 10. 2 mg. kg-1 FW, to 524 mg. kg-1 FW with a mean of 163. 5 mg kg-1FW, which was in accordance with world normal range. Assuming 200 mg kg-1 FW as the European nitrate limit in potato tubers, it exceeded from this level in about 30% of the tuber samples, and assuming 246 mg kg-1 FW as the Iranian nitrate limit, it exceeded from this level in about 20% of the tuber samples. Results showed that harvest season could affect nitrate content in potato tuber. Mean nitrate content in potato tubers taken from Fruit and Vegetables Supply Center of Tehran during spring-summer was 216. 55 mg kg-1 FW, and for samples taken during autumn-winter, it was 131. 53 mg kg-1FW.

The purpose of the study was to investigate the effect of nano-nitrogen chelate fertilizer application on a number of sugarcane characteristics (cultivar CP69-1062) and the feasibility of using digital image analysis method to determine the percentage of sugarcane seedlings green cover. The research was conducted at Mirza Kuchak Khan Aagro-industry Corporation located 65 km southwest of Ahwaz, Iran, in 2017. Statistical design was randomized complete block with five treatments and three replications. On the 15th day after cultivation, treatments were carried out in the field and included spraying different concentrations of urea fertilizer and nano-nitrogen chelate: T0= without fertilizer spraying (control), U1= urea spraying (concentration 0. 2%), U2= urea spraying (concentration 0. 3%), N1= nano-nitrogen chelate spraying (concentration 0. 4%), and N2= nano-nitrogen chelate spraying (concentration 0. 6%). Counts of buds and seedling sampling (to determine leaf nitrogen percentage) continued weekly for 12 weeks. In each experimental plot, digital photos were taken weekly and the green vegetation cover in these images was determined by Canopeo software. The results showed that experimental treatments did not have significant effect on seedling height, but had significant effects on germination percentage (p ≤ 0. 05), leaf nitrogen, and seedling vegetation (p ≤ 0. 01). Comparison of average vegetation percentage of seedlings by Duncan method showed a significant difference between all treatments compared to the control. Comparison of average vegetation percentage of seedlings showed significant differences (p ≤ 0. 01) between all treatments compared to the control. There was significant difference between U1 and U2 treatments with N1 and N2 treatments. Also, the highest mean for germination number, leaf nitrogen content, and vegetation percentage was observed in N2 treatment. Significant correlation (R2 = 90. 67%) was observed between weekly germination of sugarcane with green vegetation of seedlings, which can be used for grading sugarcane cultivation.

Hydrochar is a carbonaceous solid material obtained from hydrothermal carbonization (HTC) of biomass and has received more attention as a potential agent for soil contaminants stabilization and soil improvement. Physical and chemical properties of hydrochar are affected by the feedstock nature and production processes (HTC temperature and reaction time). The aim of this work was investigation of some properties of hydrochars produced from apple pruning wastes at temperatures of 180, 200, and 220 ° C and 6, 9, and 12 h reaction times. In addition, the effect of the hydrochar produced at 180 ° C and 12 h on availability of some nutrients in soil and corn growth was investigated. The results showed that pH of solid and liquid fractions of hydrochars were in the range of 5. 7-6. 9 and 3. 5-4. 1, respectively. By increasing conversion temperature and reaction time, the hydrochar yield and the pH of the liquid fraction were decreased, but pH and concentrations of P, Ca, Mg, and ash of solid fraction and concentrations of N, P, Ca, Mg, Fe, Mn, Cu and Zn and EC of liquid fraction were increased. Findings from this work suggested that HTC at higher temperatures increased elements concentrations in both solid and liquid fractions, and may be useful for agricultural aims. The results of the greenhouse experiment showed that hydrochar increased the availability of P added to the soil and the corn P uptake.

Absorbed cadmium (Cd) in the body is the source of many known cancers. The absorption of Cd through tobacco smoke inhalation is much greater than drinking and eating Cd contaminated food. This research was carried out to investigate the effect of irrigation salinity, TSP, and Cd contamination on the concentration of Cd in the ash, tobacco smoke, and the fate of Cd in the different soil fractions. The experiment was done with three factors of irrigation salinity (0, 20, and 40 mM NaCl), TSP (0 and 1. 5 g. kg-1 soil), and contamination of Cd added to the soil (0 and 12 mg. kg-1 soil) by factorial arrangement in a completely randomized design with four replications. The results showed that the highest concentration of Cd in the Cd contaminated soil was observed in carbonate fraction with a total average of 6. 84 mg. kg-1, and the lowest Cd concentration was observed in the iron oxide fraction with a total average of 0. 4 mg. kg-1. Application of TSP in the Cd contaminated soil in salinity of 0, 20, and 40 mM increased the concentration of Cd in tobacco ash by 1. 47%, 15. 98%, and 29. 87 percent, and the concentration of Cd in smoke increased by 23. 20%, 23. 30%, and 18%, respectively, compared to the control treatment. By increasing the salinity levels in Cd contaminated soils, Cd concentration of solution+exchangeable fraction in 20 and 40 Mm salinity, was increased with an average of 22. 15% and 42 percent, respectively. This increase was significant at 5% level. Application of TSP in Cd contaminated soils and at levels of 20 and 40 mM salinity resulted in a decrease of 14. 65% and 12% in solution + exchange Cd concentration compared to the control. The interaction of irrigation salinity with phosphate fertilizer had a synergistic effect on the concentration of Cd in ash and tobacco smoke.

Biochar is an absorbent material that can reduce the availability of heavy metals. A greenhouse experiment was carried out in factorial arrangement using completely randomized design to examine the influence of biochar, nickel (Ni) and their interaction on the growth and concentration of Ni and some micronutrients in corn grown on a calcareous soil. Treatments consisted of three biochar levels (0, 2, and 4 % w/w) and three Ni levels (0, 50 and 100 mg/kg soil as nickel sulfate) in three replicates. The results indicated that biochar significantly increased corn dry weight, chlorophyll index, and LAI. However, nickel application had no significant effect on the dry weight of corn. Biochar application significantly decreased Ni concentration in corn aerial part by 33%. Increasing Ni levels increased concentration of this element in corn shoot. Zinc, Mn, and Fe concentration significantly decreased with biochar application. Ni application decreased Fe and Mn concentration in corn. Considering the positive role of biochar on dry weight, chlorophyll greenness, and LAI, and decreasing Ni concentration in corn aerial part, it can be suggested that biochar application might be useful in soils contaminated with Ni.

In developing new pedotransfer functions, finding new input variables is a major challenge for improving the estimation of soil hydraulic properties. In this study, behavior of soils under compaction along with some basic soil properties were used as new inputs for the estimation of saturated hydraulic conductivity (Ks) of 120 soil samples from five provinces, namely, Mazandaran, West and East Azarbaijan, Kermanshah, and Hamadan. The Ks was estimated using Atterberg limits (liquid limit, plastic limit and shrinkage limit), confined compression curve parameters and basic soil properties (silt/sand, clay percentage and bulk density) as predictors, at 3 steps. At the first step, only the basic soil properties were used as predictors. Pedotransfer functions developed by regression method showed that step 2, with the inputs of confined compression curve parameters, and step 3, with the inputs of only Atterberg limits, both along with basic soil properties, led to relative improvement in the Ks estimates. The root mean square error (RMSE) values in training and testing of the steps 1, 2, and 3 were 0. 624, 0. 620, 0. 584 and 0. 887, 0. 821, 0. 829, respectively. According to RMSE criterion, relative improvement values for the training of the second and third steps were 0. 64% and 6. 35% and for the testing of the second and third steps were 7. 55% and 6. 33%, respectively. According to the R2adj entering confined compression curve parameters or Atterberg limits along with the basic soil properties could not improve the estimations. Accuracy of the third step (according to RMSE and Akaike’ s information criterion) and reliability of the second and third steps (according to RMSE and Akaike’ s information criterion) were improved in comparison with the first step.

Diffusion-dispersion and the other parameters of solute transport are important characteristics in material transportation within soil that can be influenced by several factors including addition of soil amendments and organic materials. Therefore, this research aimed to evaluate the effects of cattle manure and palm residue biochars produced at different pyrolysis temperatures on the diffusiondispersion coefficient (D) of chloride, saturated hydraulic conductivity (K), immobile water content (θ im), and mass exchange coefficient (α ) of chloride in a sandy loam soil. Treatments consisted of control, cattle manure (CMB), and palm residue (PRB) biochar produced at 400 and 600 ˚ C (CMB400, CMB600, PRB400, and PRB600, respectively). Each biochar type was applied at three levels of 0. 5, 1, and 2 % wt. The experiment was conducted using a completely randomized design with three replications on soil columns under laboratory condition after 70 days incubation. Application of 0. 5, 1 and 2% PRB400, and PRB600 increased D parameter by 89%, 80%, 40%; and 39%, 141%, 139% as compared to that of control, respectively. Furthermore, application of 0. 5%, 1%, and 2% CMB400 and 1% and 2% CMB600 significantly increased D parameter by nearly 95%, 48%, 95%; and 81% and 159% as compared to the control, respectively. On the contrary, application of 1% CMB600 had no significant effect on D parameter as compared to the control. Besides, application of 0. 5% and 1% CMB400 and application of 2% CMB600 resulted in significant increases by 24%, 18%, and 29% in K as compared to the control. Application of 0. 5% PRB400 and 1% and 2% PRB600 increased K by 24%, 20%, and 18% as compared to the control, respectively. In general, application of CMB and PRB increased the θ im and α in the studied soil. In the present study, there were no significant differences between the effect of CMB and PRB and the applied temperatures (except for the effect of PRB on D parameter) on the studied hydraulic characteristics of the soil. Results suggest that although biochar may have positive effects on different soil properties, application of both studied biochars may intensify transportation of the solute and chloride and their entrance into water resources, particularly ground waters, by increasing the hydraulic and solute transportation coefficients. This point should be considered in the application of these soil amendments.