جستجوی مقالات مرتبط با کلیدواژه "حاصلخیزی خاک" در نشریات گروه "آب و خاک"

Evaluating the spatial variability of soil properties is an important prerequisite for precision agriculture. This research was conducted on 84 soil samples from different areas of Chadegan city (Isfahan province). With the aim of evaluating the spatial variability of some soil nutrient elements, including organic carbon, soil-available phosphorus, potassium, zinc, copper, manganese, and iron. The spatial correlation of each variable with a specific semi-variable and the best fitting model for each variable were selected. Interpolation was done using normal Kriging and Inverse Distance Weighting with powers of 1 to 3 methods. The accuracy of the distribution maps of these variables was evaluated by the Mean bias error (MBE) the standard root mean square error (NRMSE), and the coefficient of determination (R2). The results showed that all studied properties had moderate spatial dependence, which shows the effect of management factors such as fertilization, plowing, irrigation, etc. on these variables. The exponential model was the most accurate to predict organic carbon, phosphorus, potassium and zink variables while iron, copper, and manganese were best fitted with an spherical model. For phosphorus, iron, and copper variables, the Inverse Distance Weighting with the power of 1 (IDW-1) and for organic carbon, potassium, zinc, and manganese normal kriging methods were recognized as the best interpolation methods. According to the spatial distribution maps, the studied area is sufficient in terms of potassium, copper and manganese nutrients, and in other cases, the use of fertilizers and organic materials is necessary to increase soil fertility.

Cadmium is one of the heavy metals, which the results of recent research indicate the severe biological toxicity, irreversibility, accumulation and non-degradability of this element in nature, and its accumulation in the soil causes a decrease in soil fertility and crop yields. One of the ways to improve the fertility of contaminated soils is the use of waste materials such as fly ash and its derivatives. The aim of this study was to investigate the effect of fly ash derivatives and genotype treatments on rice yield. The experiments of two cropping years 2019-2020 and 2020-2021 were performed in two forms of field and pot cultivation in private lands located in Kheyber town of Dezful city. This research was done by split plot method and in the form of randomized complete block design. The main factor included four amendments; soil with zero ash (as control), ash, intermediate material and zeolite. The sub-factor included two cultivars; Champa and Anbarbo. The studied traits are grain yield and plant dry weight. Comparison of treatment averages were done by Duncan's method and at two probability levels of 1% and 5%. According to the results, the effect of fly ash treatment and its derivatives on rice yield had a significant effect at 1% level. Genotype also had a significant effect on rice yield at 1% level. Also, the interaction effect of fly ash treatment and derivatives and genotype treatment had a significant effect on rice yield at 1% level. So that the lowest and the highest amount of yield with the amount of 3065.42 and 3555.96 kg/ha in the field experiment and 3162.54 and 3668.1 kg/ha in the pot experiment were corresponeded to the control treatment and Anbarbo variety and fly ash Champa treatments respectively. It was found that the treatment of fly ash and Champa variety was statistically higher than the other treatments at 5% level according to Duncan's test. According to the comparison results, the highest yield in both field and pot tests was observed in intermediates treatment and Champa variety.

Dryland farming is a major agricultural practice in northwest of Iran. Accurate understanding of soil fertility status is one of the basic needs of dryland agricultural system. Soil chemical properties play an important role in soil fertility. Assessing soil fertility is an essential need to identify environmental-friendly strategies leading to more sustainability in agricultural systems. Unfortunately, plant nutrients are insufficient in many dry farming areas of Iran, or soil conditions do not allow plant to uptake certain nutrients. Therefore, soil scientists focus on using commercial fertilizers and manures (rotation system and conservation tillage) to add nutrients and organic matter to soil. The fertility of soils can be further improved by cultivation of cover crops through adding organic matter to the soil which leads to a healthy soil with more macro-nutrients and micro-nutrients content and better structure. Therefore, evaluation of soil fertility is a basic tool for decision management in drylands and estimation of capacity of soil to maintain a continuous supply of plant nutrients for a crop production. Evaluation of soil fertility in drylands of the northwest Iran have two objectives 1) Assess nutrient status of soil-crop system 2) Diagnose suspected nutrient imbalances.

This study was carried out in northwest of Iran drylands including: west Azarbayjan, east Azarbayjan, Kurdistan and Kermanshah provinces. A total of 674 soil samples were collected from farmer’s fields in east Azarbayjan, west Azarbayjan, Kurdistan and Kermanshah 414, 97, 90 and 73 samples, respectively. The surface soil samples were taken from 0-25 cm depth in each field before the sowing of the rainfed plants in autumn by composite sampling method. After collection, soil samples were immediately dried, grounded, screened through 2 mm sieve, labelled and stored in plastic container. The samples were analyzed for 12 chemical and physical parameters include: soil texture (hydrometer method), pH (saturation paste) and EC (saturated extract), organic carbon, Total N (Kejeltak), calcium carbonate equivalence (acid-neutralizing value), phosphorus (Olsen), potassium (sodium bicarbonate extracted) and iron, zinc, Mn and copper (DTPA extracted). Soil samples were categorized as low, medium and high on the basis of their availability in soils by two Gomes (1985) (equation 1) and common (nutrient classification by critical level method for dryland wheat) methods. Low Medium Equation (1) High Where, , and SD are soil property, average of soil property in all area and standard deviation of soil property, respectively. In order to compare the levels of soil fertility of one province with those of another it is necessary to obtain a single value for each nutrient. Nutrient index value (NIV) was calculated by Parker et al., (1951) method (equation 2) for soil samples of each province or district from the proportion of soils under low, medium and high categories using following equation: Equation (2) Where, , and are number of samples testing low, medium and high category in each province, respectively. If the NIV is less than 1.67, the soil fertility status is low, the value of 1.67-2.33 reveals optimum fertility (sufficient nutrients). The values greater than 2.33 denote high fertility status.

The results showed that, the Gomes (1985) method could not classify the soil properties in all studied regions (population) correctly, due to the tends towards central limit theorem (optimal condition). Calculation of NIV showed that using conventional method (critical levels) for classification of soil properties was better than Gomes (1985) method because it was more compatible with the field conditions. The results revealed that soil salinity and calcium carbonate did not seriously make problems in dryland areas. However, increasing the amount of calcium carbonate decreased soil phosphorus, potassium, Fe, Mn, Zn and Cu, significantly. Soil phosphorus and Zn were more influenced by increasing calcium carbonate. Assessment of soil fertility status by NIV showed that, soil organic matter was low (deficient) in west and east Azerbaijan with 92 and 69 percent of those areas. But total nitrogen was optimum (sufficient) in all areas with 98 percent averagely (except east Azarbayjan). This is mainly due to the application of nitrogen fertilizers in wheat drylands and conservation tillage system in some areas. Soil phosphorus was evaluated low in two west Azerbaijan (81%) and Kermanshah (67%) provinces, but in east Azerbaijan (68 %) and Kurdistan (85%) were sufficiency or high for wheat production. Potassium was more than sufficiency (high) in 90 percent of all areas averagely. Micronutrients deficiency were observed in some provinces. The results showed the deficiency of Fe with 100 and 69 percent in west Azarbayjan and Kurdistan, respectively. Deficiency of Mn with 89 percent of west Azarbayjan, Zn with 84 percent in east Azarbayjan and Cu with 100 and 87 percent in west and east Azarbayjan were also the other obtained results of this study, respectively. The results of present study suggested that nitrogen and phosphorus fertilizer applications can also be important in micronutrient management in dryland areas.

It can be concluded that the capability of critical level method is better than Gomes (1985) method in classification of soil properties. Nutrient index value (NIV) method can efficiently evaluate soil fertility status in Iran drylands. According to this research, Fe, Zn and Cu nutrient deficiencies are just as important as P and N deficiencies in Iran dryland areas.

Animal manures are valuable organic sources for soil organic matter and crop nutrition. To evaluate the residual effects of two sources of animal manure on growth and yield of winter wheat (Triticum aestivum L) Zarin variety, a field experiment was conducted at Miandoab Research Station, Agricultural and Natural Resource Research and Educational Center of West Azerbaijan, Iran. Manures were used in 2014. In the next three years, no animal manure was applied. Residual effects of manures were determined during winter growing season of 2017-19. The treatments included T1= control, T2= 50 t ha-1 cow manure, T3= 100 t ha-1 cow manure, T4= 50 t ha-1 sheep manure, and T5= 100 t ha-1 sheep manure and were used in a randomized complete block design (RCBD) with three replications. None of the plots received mineral fertilizers. The results showed that the sheep manure was more efficient than the cow manure. Plots receiving 50 t ha-1 sheep manure showed higher grain yield and harvesting index of 36% and 17%, respectively, compared to control plots, whereas, 100 t ha-1 sheep manure did not show significant yield increase compared to the T4. Significantly higher nitrogen (1.84%), potassium (0.41%), magnesium (0.12%), iron (126.40 mg.kg-1), copper (16.4 mg.kg-1), zinc (45.7 mg.kg-1) and manganese (33.35 mg.kg-1) content in grain and highest potassium (1.76%), iron (269.3 mg.kg-1), zinc (9.16 mg.kg-1) and manganese (24.08 mg.kg-1) content in wheat straw were recorded under treatment T4. The overall results indicate that organic carbon and availability of nutrients, particularly P, Zn, and Fe in the soil surface layer were significantly higher in plots receiving manures compared to the control. Before the experiment, soil organic carbon (SOC) was 0.88%. After harvest, SOC in treatments of 50 and 100 t ha-1  of cow manure increased to 0.99% and 1.36%, and in treatments of 50 and 100 t ha-1 of sheep manure, it increased to 0.94% and 1.26%, respectively. The Results demonstrated that manure application, due to its role in soil fertility improvement, is an effective strategy for efficient production of wheat and enrichment of its grain.

The rapid growth in world population and its consequent increasing food demand require a scientific approach to paddy field productivity. To further increase rice production, the best solution is enhancing the rice yields per unit area. There are numerous integrated indices that can clarify the soil conditions and fertility characteristics, in which the integrated fertility index (IFI) is more practical. Therefore, the current study will explore soil fertility status of paddy field using IFI equation, and more broadly to issue suitable solutions for paddy soil management. This study was undertaken at Goldasht research station of the rice research institute of Iran-Amol. One hundred and twenty-eight paddy soil composite samples of plowing layer (depths of 0 to 30 cm) with a constant interval were collected to analyze for some physical and chemical properties based on rice soil requirements. Fuzzy logic theory, Principal component analysis (PCA) and IFI concepts were used for quantitative ranking of qualitative soil characters, weighing of soil properties and integration of studied soil characters, respectively. The results indicated that IFI values varied from 0.03 to 0.20. The studied paddy fields were divided into 4 individual parts through IFI values mapping method. At lower values of IFI (low soil fertility), pH, available P, OC and less broadly total N were lower than their critical levels for proper rice growth and development. Interestingly at higher values of IFI, OC and total N limitation still existed. It can be concluded that organic carbon limitation in all studied plots had negative and unavoidable effects on not only paddy soil fertility status (a vital role for sorption and desorption of soil nutrients), but also soil physical characters (enhancing soil structure, porosity, and water retention). The findings of current study also showed that the integrated fertility indices not only can show the most important limitations for rice production but also can issue the effective solutions to remediate these limitations. Key words: Rice, soil fertility, integrated fertility index, fuzzy logic, geostatistics

Understanding the capability of soils and land use limitations is a key factor in allocating the lands to the most appropriate use and also improving the growth conditions of plants in those lands. This research aimed to study the soils and recognize their limitations in cypress forest of Mobarakeh Steel Complex in order to prevent deterioration and decline of the trees. In the first step, plots were selected in the forest and a soil profiles was drilled in each plot. Soil samples were collected from the profiles. Also, soil and leaf samples were collected from the canopy of the healthy and unhealthy trees, separately. The results indicated that the soils have variety of limitations, including high gravel content (more than 50%), lack of organic matter (less than 0.5%) and nutrients, high calcium carbonate and pH coupled with soil compaction. There was a significant difference in the uptake of iron, manganese, zinc, copper, chlorine and sodium from the soil between healthy and unhealthy cypress trees. To improve the soil conditions in order to prevent the decline of cultivated trees, soil fertility and plant nutrition management program should be considered in the study area. Also, the use of organic fertilizers is recommended.

This research was carried out to compare the methods of determining the spatial distribution of soil organic carbon and nitrogen on 50,000 hectares of Lenjanat area in Isfahan province, central Iran. The spatial distribution of elements was determined by Ordinary Kriging, Inverse Distance Weighting, and Spline Tension interpolation methods. The results indicated that there was an average spatial structure in the variables. Empirical variograms showed that there was no specific anisotropy process for variables. In order to determine the accuracy of the estimation of interpolation methods, the standard data (150 data for each variable) and statistical criteria including Mean Estimation Error (MEE), Mean Square Estimation Error (MSEE), Root Mean Square Error (RMSE), relative Error (Er) and Pearson correlation coefficient (r) were used. Despite the high spatial variability of the parameters, the results indicate the accuracy of the estimated values by means of interpolation methods. For soil organic carbon in the study area, Ordinary Kriging and Spline Tension interpolation methods with lower error (MEE= 0.007, MSEE= 0.09, RMSE= 0.3, Er= 0.32 and r= 0.73) were more accurate compared with the Inverse Distance Weighting interpolation method (MEE= 0.009, MSEE= 0.096, RMSE= 0.31, Er= 0.31 and r= 0.71). Also, Ordinary Kriging and Inverse Distance Weighting interpolation methods with a lower error (MEE= 0.003, MSEE= 0.0006, RMSE= 0.025, Er= 0.296 and r= 0.8), compared with Spline Tension interpolation method (MEE= 0.0017, MSEE= 0.0007, RMSE= 0.026, Er= 0.301 and r= 0.78) had more accurate estimation of soil nitrogen in the region.

Pyrolysis of feedstocks and producing biochar is a suitable technique for agricultural wastes management, carbon sequestration and soil amelioration. The study of structural and physicochemical properties of biochars, which are strongly dependent on the type of feedstock and pyrolysis temperature, is very important to identify the suitable application of biochar in the soil. The objective of this research was to investigate the properties changes of biochars derived from corn residue and sugarcane bagasse under different pyrolysis temperatures. This study was carried out under laboratory conditions based on a randomized complete design with eight treatments of corn residue, sugarcane bagasse and their biochars and in three replications. Biochars were produced at 200, 350 and 500˚C pyrolysis temperatures under slow pyrolysis conditions. Results indicated that increasing pyrolysis temperature from 200 to 500˚C, in corn residue and sugarcane bagasse treatments, decreased the yield (29.24 and 23.6% respectively), volatile matter (29.8 and 32.5%), cation exchange capacity (32.5 and 29.8%) and the ratios of C/N, H/C and O/C while led to increase the ash content of corn residue and sugarcane bagasse biochars (20.3 and 42.3% respectively), fixed carbon (23.2 and 14.7%), pH, EC, aromatic compounds and nutrients concentration. Concentration of nitrogen, phosphorus, potassium were greater in the corn residue than in the sugarcane bagasse treatments, but the C/N ratio were greater in the sugarcane bagasse treatments. Based on the results of this study, it could be concluded that biochars produced at 500˚C temperature can be more effective in carbon sequestration in the soil, whereas biochars produced at 200 and 350˚C temperatures are more suitable for improving soil fertility.

In this research, the short-term beneficial effect of using different pistachio wastes biochars on improving some fertility properties of a loam soil was investigated. Therefore, the effects of two factors 1) types of amendments added to the soil, including biochars of pistachio mildew (PM), pistachio hard skin (PHS) and wood of 20-year pistachio trees (W) papered at 600o C (with amount of %5 by wt), and 2) time of incubation (1, 2, 3, 4, 5 months), were investigated on pH, electrical conductivity, soluble potassium, nitrate and availability of iron, copper, manganese and zinc. This experiment was performed as factorial based on the completely randomized design with three replicates. The results of this study showed that the application of biochars and different incubation times does not have a significant effect on soil pH. But, the threated soils at all incubation times showed a significant increase in electrical conductivity and organic carbon as compared to the control treatment. Addition of biochars and incubation time increased significantly potassium content of the soil solution, so that the treated soils had an increase of approximately two times solution potassium as compared to the control. Application of biochars to the soil caused an increase in nitrate retention and a decrease in nitrate solution as compared to the control sample. Biochars application led to a significant increase in iron content and irregular increase in zinc, copper and manganese. The availability of these elements in the soil decreased by time due to reduction of biochar decomposition and transformation of those elements from available into less available forms.

Soil fertility describes the ability of soil to create the conditions for sustainable growth, optimum plant. The elements in the soil productive effects on soil structure, soil texture, water retention in the soil, water infiltration in the soil. On the other hand, with respect to the elements in the soil, the manure is used for different plants. One of the major goals of modern agriculture, efficient use of fertilizers. The use of chemical fertilizers, regardless of the elements in the soil, causing the balance of nutrients, loss of energy and environmental problems. So to determine the fertility of the soil due to fertilizer and plant species to determine the next Managing agricultural land is important. The parameters such as potassium, phosphorus, organic matter, copper, manganese, zinc and iron were studied. For this purpose, the data of 38 soil samples were used. Average Inverse Distance method (IDW) for mapping each element was used in GIS. In order to homogenize the data to produce a map of soil fertility phase method was used. Fuzzy membership functions were prepared using standard soil fertility. Finally, in order to ensure a different level of soil fertility maps sorted by weighted average (OWA) was used. The final results of soil fertility study area using OWA showed that risk appetite (no trade-off) is most problematic area in terms of soil fertility. So that the results showed that the class 4 and 5 areas with fertile soil and good average in the study area show a greater area than the rest of their class. However, with increasing levels of reliability and reduce the risk areas was more difficult in terms of soil fertility. So that more area in the classroom is one that has a poor soil fertility.

In order to study of effect of saline water and soil fertility stresses on the evapotranspiration of maize, a factorial experiment was conducted in a randomized complete blocks design, in the research farm of Imam Khomeini International University, in 2017. Water salinity treatments consisted of four levels; 0.5(S_0 ), 2.1(S_1 ), 3.5(S_2 ) and 5.7(S_3 ) d_s/m and Soil fertilization treatments consisted of four levels of need to nitrogen fertilizer; 100(F_0 ), 75(F_1 ), 50(F_2 ) and 25 percent (F_3 ), was conducted In three repetitions and in plots with an area of 9 square meters. By measuring the soil moisture at the root zone, at intervals between two irrigations, was investigated the difference of water absorption by stressed plots relative to non-stress plot. The results showed that by changing the salinity of irrigation water from 0.5 to 5.7 (d_s/m), in fertolity levels of F_0, F_1, F_2 and F_3, the stress coefficient of evapotranspiration (K_S ) has been; 0.77, 0.69, 0.64 and 0.6, respectively. Also, by changing the fertility level from F_0 to F_3, in salinity levels of S_0, S_1, S_2 and S_3, the K_S has been; 0.96, 0.88, 0.83 and 0.63, respectively. From treatment of S_0 F_0 to S_3 F_3, were reduced the evapotranspiration, K_S coeffition and crop yield to; 37, 37 and 38 percent, respectively. Are fitted different forms of production functions, to estimation of evapotranspiration from salinity and fertility stresses. The quadratic function was chosen as the optimal function due to having the statistics of RMSE and ME at least and R^2 and EF close to number one. The salinity and fertility stresses, has a reducer effect on the amount of evapotranspiration of plant. Therefore, by correct determination of water requirement of under stress plant, you can avoid than consumption of a lot water.

Most of soil physical, chemical and biological properties change by fire. Fire can influence forest soils fertility by altering nutrients content and availability. In order to investigate fire impact and different firing background on some soil chemical properties, 80 soil samples were taken from two depths (0-5 cm and 5-20 cm) with different time of firing background (6 and 12 months). Total nitrogen, phosphorus, potassium, manganese, iron, zinc, copper and organic carbon were measured in soil samples. The results showed that there was a significant difference in the amount of phosphorus and nitrogen between burned and control soils. The amount of studied indices increased after firing in burned soils compared to control ones, however one year later they reach to their pre-fire levels. Phosphorus and coarse fraction carbon (0.25-2 mm) in burned soils were 2.23 and 2.53 times higher as compared to unfired samples, respectively. Manganeseamount in soils with 6 months firing history increased 32.7 percent in comparison to control soils, but one year after firing its content decreased. The most potassium amount (392 mg kg-1) observed in burned soils with 12 months history of burn. Therefore forest firing causes obvious changes in soil properties but these changes are not permanent and depending on fire intensity, impression permanency duration is different.

Land leveling and consolidation of paddy soils is a key approach in precision agriculture for water management improvement, weed control and agricultural mechanization. However, nutrients spatial variability in these fields is affected by land leveling. The objective of this study was to determine land leveling effect on the degree of spatial variability of soil fertitility. Land leveling caused significant spatial variability and spatial distribution of soil fertility properties. Clay content significantly increased, while soil organic carbon, total nitrogen, available phosphorous and available potassium significantly decreased. Alteration of spatial distribution was due to cut off the top soil at higher locations and its deposition on the low areas. The post-leveling evaluation of soil several fertility status with geostatistics demonstrated that leveled field faced with deficiency in one or several nutrients. The traditional fertilizer recommendation for whole field would accelerate non- uniformity in soil fertility status and would not lead to realization of the potential.

Nowadays, fuzzy technique is used to prepare the map in different sciences, extensively. With due attention to important role of soil fertility in modern agriculture, the preparation of soil fertility map seems to be necessary to plan for appropriate using of fertilizers for crops. This study was conducted to prepare a distinct map for evaluating soil fertility according to soil available K and P, and soil organic matter factors in Shavor region in Khuzestan province. The fuzzy technique and the Analytic Hierarchy Process (AHP) were used for mapping soil fertility into Geographic Information System (GIS). For this, the amount of soil organic matter, and available soil phosphorus and potassium obtained form 282 profiles of soil, as the input data, were used. In the first stage the interpolation of data was done by Inverse Distance Weighting (IDW) model into GIS. Then a membership functions was defined for each factor. Finally, the map of soil fertility was prepared by using AHP technique into program of Expert Choice with adjustment rate of 0.05. Results showed that 51, 26, 12 and 11 percentage of lands were classified base on soil fertility into groups of very weak, weak, moderate and suitable, respectively. As a final result, this types of distinct soil fertility map can able us to manage the appropriate using of fertilizer.