نشریه پژوهشهای خاک (علوم خاک و آب)
سال سی و هفتم شماره 3 (پاییز 1402)

This study expresses the steps of achievement to the indigenous-executive framework of integrated soil and water management at farm level through a mega project with 19 sub-projects. The projects were carried out during 2013-2020 with active participation of international, national and regional experts as well as local farmers in Honam Sub-basin, Lorestan Province, Iran. To understand the soil and water management problems for agriculture in the same homogeneous units (HSWMUs), farmlands were classified regarding physical, chemical and biological characteristics of soil, making it possible to convert soil maps into thematic maps. In this research, the fertility capability classification (FCC) method that integrates surface and sub-surface soil textures with modifieres was used. In addition, several modifieres were revised for soils of semi-arid regions and new modifieres were introduced for Irrigation Capability Classification (ICC). The required information was collected from 119 soil profiles and 101 surface soil samples in detailed scale of 1:25000 and the corresponding measurements were made. Accordingly, different data layers including detailed soil map were produced via geopedological method icluding land limitation, land suitability, and land production potential (LPP) of major crops, land degradation, location of water withdrawal, land use and agricultural cadastre of 2395 farms were prepared. To evaluate the current soil and water behavior of farmers within HSWMUs, the multidisciplinary team recorded the issues through field visits and open semi-structured questionnaire of 84 selected farmers in 24 villages who were interviewed during 2018-2019. The results showed that 23 and 30 HSWMUs that covered, respectively, 93% and 90% of the irrigated and rainfed areas were delineated on the map. Investigations showed that the sub-basin suffers from problems such as plow pan, phosphorus and zinc deficiencies, poor irrigation scheduling, and three types of farmers. Finally, recommended packages were prepared and validated for each HSWMU, which will be discussed in the part 2.

This experiment was conducted to evaluate the effect of soil moisture and tillage and sowing machinery on yield and yield components of wheat in the saline soils of Mahshahr, Iran. The experiment was carried out as a split-plot according to a randomized complete block design with three replications. Independent variables included soil moisture during tillage at three levels of 10%, 15%, and 20% as the main factor. Sub-factor included the type of tillage and sowing machinery at four levels including 1) without the use of chisel-piler and sowing with flat seeder machine, 2) without the use of chisel-piler and sowing with furrow seeder machine, 3) one time use of chisel-piler to a depth of 20 cm and sowing with flat seeder machine, and 4) one time use of chisel-piler to a depth of 20 cm and sowing with furrow seeder machine. In order to prepare the land, irrigation was done before tillage according to the region's customs to reduce the tensile strength of the soil against tillage machines. After the soil moisture was suitable according to the main factors, the tillage was done with a 24-bladed disk machine once to a depth of 15 cm. The maximum clod weight was obtained in the condition of not using a chisel-piler and soil moisture of 20%, and the lowest was obtained in using a chisel-piler and soil moisture of 10%. The maximum number of tiller/plant, number of spikes/m2, number of spikelet/spike, number of grain/spike, number of grain/spikelet, biological yield, and grain yield was under using chisel-piler and sowing with furrow seeder machine with 20% soil moisture, and the lowest in the treatment with no chisel-piler and sowing with flat seeder machine. In general, the results showed that the use of chisel-piler and sowing with furrow seeder machine under 20% soil moisture had the best results in terms of grain formation and yield in saline soils, which can be suggested to reduce the effects of salinity.

To apply sludge in agriculture, knowing its effects and transfer of heavy metals to plant is vital. For this purpose, a greenhouse experiment was conducted in the form of randomized complete block design in 2021, in the greenhouse of Soil and Water Research Institute in Karaj, Iran, to investigate the accumulation of heavy metals in forage corn grown in soil treated with different levels of sludge. The selected soil was treated with 4 different levels of urban sewage sludge at the rate of 0%, 0.5%, 2%, and 4%, with 3 replications. The results showed that, compared to the control treatment, all treatments using sludge increased wet and dry yield (P<0.05). The highest yield of shoot with an average of 214.9 gr per pot (300% increase) was obtained from the use of 4% sludge, and this treatment had a significant difference compared to the other levels of sludge (p<0.05). Compared to each other, sludge treatments did not have a significant effect on dry yield. Use of sewage sludge caused a significant increase in the concentration of Pb, Ni and Cu elements in the shoot of corn. The value of the transfer factor (TF) among the studied elements in all treatments was as follows: Cd>Cu>Pb>Ni>As>Cr>Co, where the highest average value of the TF was related to the Cd, followed by copper and Pb. Sewage sludge caused significant changes in the TF of Cd, Ni, As, Cu and Pb compared to the control. However, these changes were not significant for Cr and Co (p<0.05). The average value of root BCFroot had the following trend: Cd>Cu>Pb>Ni>As>Co>Cr. The trend for BCFshoot was as follows: Cd>Pb>Cu>Ni>As>Cr>Co. Among the investigated heavy metals, the BCF of Cd for roots and shoots, as well as its transfer factor, was higher than other heavy metals. In general, the highest concentrations for Cd, Pb and As in the shoot of the corn were 0.17, 1.94, and 0.74 mg/kg, respectively, while the permissible values of the maximum standard tolerance in livestock feed for animals raw materials from plant sources are 1, 30, and 2 mg/kg, respectively. Therefore, the increase in the concentration in the shoots was not more than the permissible limits in the national standard of Iran. However, it should be noted that the results of this investigation were only related to one-time use of the sludge sample, while the quality and contents of sludge have many variations. Considering deficiency of organic matter and phosphorus in the country's agricultural soils, the use of treated sewage sludge should be considered due to its high percentage of organic carbon and phosphorus. However, due to the changes in the quality of sludge and its multiple uses in cultivated lands, it is suggested that additional studies be conducted for different sludge in order to provide a specific agronomic recommendation based on that.

Tea is a permanent and evergreen plant that grows adeptly in acidic soils. The tea plant naturally absorbs aluminum and accumulates it in various shoot parts. Although aluminum is essential for tea growth, it is harmful to human health. Evaluating aluminum status in both soils and tea green leaves is necessary to better understand their relationships in order to improve the quality as well as quantity of tea yields. For this purpose, 38 samples of the soils and the third green leaves of tea (as an index leaf) were collected randomly from tea plantations of Guilan Province. In soil samples, besides the general properties, the values of pHw, pHCaCl2, exchangeable aluminum, calcium and magnesium, total nitrogen and available concentrations of phosphorus and potassium were determined. Concentrations of the aforementioned nutrients along with iron and zinc were also evaluated in the tea leaves. Based on the results, the mean values of pHw and pHCaCl2, and the mean concentrations of soil exchangeable aluminum and leaf aluminum were 4.51, 4.04, 256 mg/kg, and 1362 mg/kg, respectively. The soil exchangeable aluminum had inverse power relationships with pHw and pHCaCl2 with the coefficients of determination of 66% and 84%, respectively. This indicated that the pHCaCl2 was more valid than pHw. Leaf Al concentration showed no significant correlation with soil pH, but had significant relationship with soil exchangeable aluminum (r=0.69**). Furthermore, the total polyphenol content of the green tea leaves had no significant correlation with leaf Al concentration, but had significant relationship with (Al/(Fe+Zn)) ratio in tea leaves (r=0.64***). According to the lower limit of optimum pH for tea plantations (pH=4.5), the maximum permissible concentration of soil exchangeable aluminum was estimated to be 153 mg/kg. In order to control soil exchangeable aluminum and adjusting soil pH, it is recommended to use lime or dolomite, based on the soil buffering capacity.

Mycorrhizal fungi are one of the useful soil microorganisms, which can increase the growth of the host plant by absorbing and transferring more water and nutrients to the plant due to symbiosis with plant roots. Therefore, in order to investigate the effect of mycorrhizal fungi on the biomass and nutrient absorption of hazelnut seedlings, a factorial experiment was conducted in the form of a randomized complete block design in field conditions. The investigated factors included the three origins of the seedlings (Fandoghlou, Makesh, and Makidi regions) and fungal inoculation in three levels (Rhizophagus irregularis, Myco root inoculum and control) with three replications of 25 at a distance of 3x3 m, in an area of 6075 m2 in the agricultural lands on the edge of Fandoghlou Forest in Ardabil, Iran. After four years, the results showed that the inoculated seedlings of all three origins were superior in terms of all the examined characteristics compared to the control (non-inoculated) seedlings. The highest traits belonged to Fandoghlou seedlings with R. irregularis inoculation. In these seedlings, root colonization, dry mass of root, stem and leaf were, respectively, 51.9%, 54.4%, 45.1%, and 40.7% higher, and N, P, K, Fe, and Zn were, respectively, 38.8%, 45.4%, 62.9%, 35.5%, and 42.6% more compared to the control seedlings. Finally, it can be concluded that planting of hazelnut seedlings inoculated with mycorrhizal fungi (especially R. irregularis) will have higher vegetative growth.

Cadmium is one of the most hazardous heavy elements in the environment, and its removal from water and soil environments is necessary and important. In the present study, the effect of poplar sawdust and its biochars at two different temperatures of 300 and 600 0C on the process of cadmium desorption in a silty loam soil was investigated in Lorestan Faculty of Agriculture, in 2021. For this purpose, poplar sawdust and its biochars were added at three levels (zero, 2%, and 4% by weight) to a calcareous soil contaminated with 100 mg/kg of cadmium. Sampling of the treated soils was done 90 days after the soil was contaminated with cadmium and incubated under field moisture conditions. To study cadmium desorption, in different time periods from 5 to 2880 minutes, the samples were extracted by EDTA and the concentration of cadmium in the samples was determined. The results showed that the lowest amount of cadmium desorption was in the 4% sawdust biochar at 600 0C, which showed a decrease of 80.5% compared to the control. Also, cadmium desorption in the sawdust treatment did not show a significant difference compared to the control. Cadmium desorption in all treatments was high in the early times and decreased over time. In other words, 50% of cadmium desorption occurred in the first 2 hours. Based on the R2 (0.94) and SE (0.23), the power function equation was obtained as the best equation predicting desorption of cadmium in the studied soil. Therefore, in this research, the treatment of 4% by weight of sawdust biochar at 600 0C is introduced as the best treatment to reduce soil pollution caused by cadmium.