نشریه مهندسی زراعی
سال چهل و چهارم شماره 3 (پاییز 1400)

The rapid growth of population demands higher land use efficiency to ensure food security. The most appropriate way to reach this goal is to increase yield per unit area. In this regard, the assessment of soil fertility and productivity is a prerequisite for developing sustainable agriculture. Soil fertility indicates the soil capability to provide optimum conditions for plant growth. Assessing soil fertility is an essential need to identify environmental-friendly strategies leading to more sustainability in agricultural systems. Soil fertility directly and indirectly affects the yield and crop quality. In order for food security and increased food production to be achieved, the development of a useful method for assessing soil fertility and productivity is fundamental. Various modeling techniques have been proposed as a useful tool to determine soil fertility. An assessment of the soil fertility status by using a soil index could provide key information to improve strategies and effective techniques for the future to achieve sustainable agriculture. The present study was conducted: (1) to determine the soil fertility index (SFI) using two methods which are conceptually different from each other including: Fuzzy-AHP and parametric methods; (2) to identify the main soil limiting factors for tea production; and (3) to compare two methods of quantitative assessment of soil fertility in relation to tea yield in tea cultivation with different productivities in west Guilan province.Materials and Methods Based on the mean annual tea yield, the selected tea cultivation were divided into low, medium, and high productivity. Sixty-six soil samples were collected from 0 to 30 cm depth. The green tea leaves were harvested at a 2 m2 plot at each site. In this research, clay, silt, and sand content, mean weight diameter of soil aggregates, bulk density, soil pH, electrical conductivity, soil organic carbon, total nitrogen, available phosphorus, available potassium, available copper, and zinc were measured by conventional methods. Then, the soil fertility indices of tea cultivation with different productivities were determined by fuzzy-analytical hierarchy process (SFI-Fuzzy AHP) and Parametric (SFI-Parametric) analyses. The Fuzzy analytical hierarchy process is a combination of factor weights of AHP with the fuzzy values of each parameter. The product of values generated from individual fuzzification of parameters with their corresponding factor weights. All soil parameters were tested using one-way analysis of variance and the differences among means were analyzed using Tukey's significant difference test at the probability level of 0.05.The coefficients of determination for the linear regression between the two SFI values and tea yields were conducted.Results and Discussion Results indicated that the effect of pH, available potassium and copper, mean weight diameter, and bulk density on tea yield was significant (p <0.01). The highest of organic carbon, mean weight diameter, available potassium and copper were obtained in high productivity. The highest of soil pH and bulk density were related to low productivity. The main soil limiting factors for tea production were soil organic carbon, available potassium, and soil pH. The results showed that for both SFI-Fuzzy AHP and SFI-Parametric methods, the highest and lowest soil fertility indices were related to high and low productivity, respectively. The mean SFI- Fuzzy AHP of the high productivity tea were significantly higher than low productivity tea cultivation. It was found that SFI- Fuzzy AHP is superior to SFI-Parametric to evaluation of soil fertility for tea production .So that, the correlations between crop yields and SFI- Fuzzy AHP (R2= 0.63) is higher than SFI-Parametric (R2= 0.50).Conclusion Understanding the soil fertility status is one of the important aspects of sustainable soil management in order to optimal crop production and prevent environmental degradation. Considering the importance of yield as an important indicator in the sustainable management of agricultural ecosystems, it is expected that there is great potential for increasing crop yield by improving soil fertility. The SFI- Fuzzy AHP of the high productivity tea were significantly higher than low productivity tea cultivation and created more differentiation between various soil fertility classes in tea cultivation. Therefore, determining the soil fertility index by Fuzzy-AHP method to evaluate the soil fertility of tea cultivation is superior to the parametric method. Based on the obtained results, it is suggested that for the optimal tea production, in addition to the application of potassium fertilizer, the exact amount of which should be estimated based on the soil test results, the organic matter application should also be considered.

Soil is the upper layer of earth in which plants grow and is consequently very important for organisms and human nutrition. The protection of the soil against degrading processes, such as soil salinization and alkalization, is one of the main challenges in sustainable land management. Soil salinization and alkalization are two major environmental concerns leading to soil degradation especially in arid and semi-arid regions across the world. The balance of organic carbon in the soil is important for soil sustainability. Intensive cultivation enhance soil organic carbon (SOC) depletion. In order to alleviate the detrimental effects of SOC depletion, carbon-rich organic amendments such as biochar or compost are often applied to the soil. Therefore application of organic amendments to soil is an effective strategy to improve soil properties and to mitigate the negative impacts of inappropriate management strategies. Biochar is a carbon-rich compound produced by the pyrolysis of biomass in oxygen-limited conditions. Its use as an organic amendment to soil with specific inherent characteristics has been recognized. In this regard recent studies have shown that application of biochar to soil as an organic amendment can improve soil physical properties and help to keep the carbon balance in the soil. Moreover, compost as an organic amendment is capable to improve soil properties and increase the soil productivity.

The soil sampling was carried out near Kabutar Khan in Rafsanjan, Iran (56°22′N, 30°18′E), on a saline-sodic soil with Silty Clay soil texture (42% silt, 50% clay and 8% sand). The biochar was obtained from three different feedstocks consist of Conocarpus erectus, bagasse of Sugarcane and hard shell of Pistacia Vera. The obtained feedstocks were pyrolyzed at 400°C for 2 h with increasing rate of 7 °C/min in a sealed reactor to prevent O2 input (Muffle Furnace, SEF-101 Model). Afterwards the produced biochar was cooled slowly to the room temperature, then the EC, pH, specific surface area and CHNS of biochars were measured using the standard methods. The required amounts of soils and biochars were weighed by a total 5000 g dry weight of sample and mixed in the dry state. The soil samples were received three doses of biochar (0, 2, 4 % biochar, w/w). The mixtures of soil and biochar were packed into pots and controlled a bulk density of about 1.5 g cm-3 by artificial compaction. Treatments were replicated three times. The soil without any biochar was used as the control. The mixtures were wetted at three soil moisture contents (25, 50 and 75% field capacity) during incubation time (120 days). The treatments were kept at a temperature-controlled glasshouse. After 120 days of incubation, the untreated soils and biochar-amended soils were taken for physical and chemical analyses.Particle size distribution was measured by hydrometer method and soil organic carbon by oxidation method with potassium dichromate. The consistency limits (liquid limit and plastic limit) of soils were determined according to the ASTMD4318 procedure. The field capacity was measured using the pressure plates with the standard rings in the lab. Mechanical strength is a sensitive indicator of the soil physical condition and has been commonly used to evaluate soil water erosion, structural stability, tillage performance, and root penetration. Higher strength found in saline-sodic soil often impedes seedling emergence and root penetration.

Our results revealed that application of organic matter in the form of biochars and compost was effective on soil aggregation. The formation and stability of the soil aggregates play an important role in the crop production and soil degradation prevention. Moreover, the biochar application showed two main effects including direct and indirect effects. Our results confirm the addition of biochar to soil can cause a substantial and significant change in the soil physical characteristics of the strongly acidic Ultisol, namely a significant increase in LL and PI, higher water-holding capacity, and reduction in mechanical strength. These changes are undoubtedly associated with the particular properties of biochar and in particular with its high porosity and low bulk density. The beneficial effect of biochars on soil physical properties is mainly due to the dilution effect of biochar with higher porosity and lower density. When the biomass is heated, volatile matters may release out of the biomass to create micropores on the surface, and meanwhile those trapped inside the biomass are evaporated to expand the microstructure. Thus, the resulting biochar has much higher surface area and porosity. These properties are particularly useful for soil application of biochar especially for enhancing soil water-holding capacity, reducing mechanical strength, and increasing soil aggregation. The dilution effect can be attributed to the increased volume of pores as well as the decreased particle density in soil amended with biochar. The effectiveness of different biochars in improving the soil physical properties can be explained by their porosity and bulk density.

Our results depicted that application of biochars and compost as an organic amendments improved mechanical quality of the saline and sodic studied soil. Indeed all organic treatments decreased bulk density and enhanced soil aggregate stability while the biochar of Conocarpus illustrated the greatest effectiveness on soil physical and mechanical properties. Therefore it is a possibility to apply this biochar to the soil in the field scale but regarding the accessibility of biochar of Pistachio skin in the study area therefor we have another alternative to utilize in the soil. This research was conducted in the small scale and in a short time. Therefore, it is suggested that supplementary studies are carry out on farm scale for a longer periods.

Investigation of effective factors on water production system using land coolingAbstractIntroduction Water scarcity has been a worrying issue and one of the obstacles to economic growth of countries, despite various water supply sources such as groundwater, seas, rivers and rainfall. Today, in many parts of the world, due to the scarcity of water resources, disputes over access to water resources have crossed national borders and access to these resources has become a strategic goal in the interaction between countries. According to statistics released by the World Resources Institute in recent years, about 35 countries will face water stress in 2040, of which Iran ranks 13th. Considering the average rainfall in Iran and also considering the amount of water resources and per capita consumption in the country, Iran is considered among the countries that are at risk of lack of physical water resources. The purpose of this study was to provide safe water for domestic use and drinking water without using fresh water sources and only with the benefit of the air humidity. In fact, the goal is to provide fresh water from the humidity, especially for remote areas and villages with small populations that do not have access to water. In this method, there is no need to use fossil and electrical energy and only wind energy, air humidity and depth of the earth are the factors of its production, and so it is also economically viable. The system considered in this research reduces the air temperature and cools it until the saturation phase by blowing the outside hot air into a buried pipe underground. In this way, some part of the air moisture is separated and appeared in the form of water droplets on the pipe wall; then the obtained water is stored in a tank and used. Materials and Methods In this research, a system was used that was partly underground and partly out of the soil. Buried sections include the copper pipes, the circuit breakers and connections, and a water tank and the sections on the ground include a cubic chamber with dimensions of 2×2 m, temperature and humidity sensors, fans, inlet air supply section, valves control levers, air conditioners, heaters and humidifiers. During the tests, the temperature and humidity inside the chamber were controlled by a microcontroller board and the effect of changes in air humidity (30, 50, 70 and 90%), air temperature (20, 30, 40 and 50 °C), inlet air flow (2.5, 5 and 7.5 m3/h , equal to the speeds of 1, 2 and 3 m/s , respectively) and the pipe effective length (2 and 4 m with a fixed diameter of 30 mm and a thickness of 1 mm) on the amount of extracted water was evaluated. The burial depth of the pipe was about 1 m and the soil temperature was measured by a sensor next to the buried pipes. The used statistical design was the split plots design in the form of completely randomized blocks and the results were analyzed and compared using SPSS software. In order to create and control different atmospheric conditions inside the chamber, it was necessary to consume electrical energy, while in the open space water can be produced from this system without the need for electrical energy.Results and Discussion the studied factors, including the pipe length, air humidity, air temperature and air flow rate (inside the pipe), affected on the amount of produced water significantly. By increasing of the air humidity, the air flow rate, the chamber air temperature and the pipe length, the amount of produced water was increased. The air temperature of 50 °C, the air velocity in 3 m/s, the humidity of 90% and 4 m length of the copper pipe had the maximum water production in a certain period of time.Conclusion The results of the present study show that water production from air humidity can be used as a method to produce fresh water, especially in remote and low populated areas with high air humidity that do not have access to the fresh water. Although the volume of water production by this method is not comparable with methods such as the multi-stage distillation, but it is economical and does not require any energy.

The use of organic fertilizers in sustainable agriculture, in addition to increasing the support and activity of beneficial soil microorganisms in order to provide plant nutrients such as nitrogen, phosphorus and soluble potassium and also improves plant growth and yield are so necessary. In pistachio growing areas due to soil constraints such as salinity and sodium content of the soil, lack of proper structure in most areas, poor soil texture and long irrigation cycle, the use of auxiliary substances such as humic acid, can improve the situation and lead to increase nutrient uptake and increase growth and yield and sustainable production.

This experiment was carried out in a randomized complete block design with three replications in MahVelat. The main plot consisted of four types of humic acid (ordinary solid humic acid, Ferti Plus solid humic acid, Iranian liquid humic acid (all three products of Shimi Gol Feyz Khorasan Company) and American Liquid Humic Acid (HUMAX) and subplot including different application levels (0, first level for solid fertilizers 600 kg and liquid fertilizers 40 liters per hectare and second level for solid fertilizers 800 kg and liquid fertilizers 60 liters per hectare). The number of trees tested was 36 trees of 10-year-old almond cultivar. Solid fertilizer was applied once (March 2016) and liquid fertilizer twice (March 2016 and May 2017). Irrigation was drip (Babler) and studies were considered for one year. In August 2017, by random sampling of the leaves of each tree, the concentration of nitrogen, phosphorus, potassium, calcium and magnesium in the plant leaves and also by sampling the soil of the foot of each tree, some soil chemical properties, including pH, Organic carbon content, available nitrogen concentration and available phosphorus concentration in soil, potassium, calcium and magnesium in soil solution extract were measured. In September 2017, yield components (weight of 100 grains, ounce and emptiness percent) of each tree were measured by weight. The results were statistically analyzed using SAS software and the mean of the experimental data were compared with each other by Duncan's multiple range tests at 5% probability level.

The amount of organic carbon (71.42%), nitrogen (72.22%), and soil potassium (43.01%) with all types of humic acids showed a significant increase compared to the control, but no significant difference was observed between the consumed humic acids. The highest amount of available phosphorus (78/30%) in soil, calcium (54/90%) and magnesium (56.05%) was obtained from liquid ShimiGol and Humax. With increasing the amount of humic acid, electrical conductivity (13.71%) decreased but organic carbon (82.88%), nitrogen (55%), phosphorus (75.93%), potassium (23.97%), calcium (46.35%) and magnesium (58.82%) showed a significant increase and the highest amount of these properties was obtained in the highest amount of humic acid consumption. The interaction of humic acid type and its amount on the amount of organic carbon, phosphorus, potassium, calcium and magnesium in the soil was significant and the highest amount of calcium (57.03%) was obtained from the application of 60 liters per hectare of Humax. The highest leaf nitrogen concentrations were obtained from the application of liquid Humax (MAX:42.23%), liquid of Shimi Gol, solid Ferti Plus and ordinary solid ShimiGol, respectively. The highest concentrations of phosphorus (17.65%) and magnesium (16.96%) were obtained from Humax and the highest concentrations of calcium were obtained from three solid humic acids, Ferti Plus, liquid of ShimiGol and liquid of Humax with a significant difference with ordinary solid. The type of humic acid consumed was not significant on any of the yield components (weight of 100 grains (21.69%), ounces (27.45%) and emptiness percent (25.38%)). The amount of humic acid consumed was significant on all measured characteristics. So that the best yield components and the highest element concentration were obtained from the highest amount of humic acid consumption.Humic acid has direct and indirect effects on plants. Indirect effect is usually in the form of changes in environmental conditions such as modification of soil physical condition, enzymatic and hormonal effects and soil pH, improvement of soil structure, aeration, drainage, water holding capacity, soil temperature and direct effects includes increasing biomass and microbial population, antiviral activity and growth modulation, increasing plant resistance to salinity and drought stress. Humic acid increases nutrient uptake, increases germination and root growth, and improves yield quantitatively and qualitatively. Humic substances also dissolve calcium carbonate in the soil and replace calcium with sodium by activating sulfur oxidizing bacteria, as well as reduction of soil pH to improve nutrient uptake. Humic acid can directly release various elements from minerals, absorb them and deliver them to the roots at the right time. Because humic acid is a valuable source of macro and micro nutrients, it provides a good nutritional balance for the plant and leads to greater absorption of nutrients and specific functional responses in the plant.

Application of humic acids in liquid or solid form, domestically or externally produced, can increase the supply of nitrogen, potassium, phosphorus, calcium, magnesium, as well as the content of organic carbon in the soil and reduce pH, increase the concentration of elements in leaves and improve yield components. Of course, it should be noted that among the internal humic acids, the solid Ferty Plus, Shimi Gol were as well as Humax liquid. Relying on internal knowledge can prevent unnecessary outflow of currency.

In recent decades, population growth has led to changes in dietary behavior and a significant increase in global demand for food production, which has led to the promotion of heavy use of agricultural land. water shortage in arid and semi-arid regions is one of the most important factor that affect crops production. The use of different conservation tillage methods such as minimum tillage and the use of organic and inorganic mulch as methods used in sustainable agriculture, can reduce water and energy consumption in an agricultural system. Soil water affects plant growth and development. So that even a small change in soil water content can significantly change the productivity of crops. Soil cover or mulch is one of the management strategies to increase water use efficiency of agricultural products.

In this study, research was conducted to investigate the effect of conservation tillage methods and plasticulture patterns on water use efficiency and strawberry crop yield in 1398. The water use efficiency was calculated to assess the effects of tillage and plastic covers in the field. . The experiment was conducted using of factorial design in the form of randomized complete blocks with three replications. The plots included two types of tillage systems (conventional and conservation) and three methods of plastic cover (planting under plastic, over plastic and without plastic coverage). This experiment was performed in 18 plots with dimensions of 0.8×15 meters. 3 rows were planted in each plot. The distance between sub-plots was 75 cm as a ridge, the distance between main plots was 1 and a half meters and the distance between replicates was 2 meters. Water use efficiency (WUE) is one of the most important indicators for measuring agricultural water productivity. This index is actually the ratio of the amount of product produced per amount of water consumed (evaporation-transpiration) of the plant. In this definition, instead of evaporating and transpiration of the plant, the amount of water used in the field can be replaced and the amount of crop production per unit volume of water used in irrigation can be obtained. The higher this ratio, the better the water consumption.

The two factors of tillage and planting pattern only affected soil moisture content at a depth of 0-10 cm and no significant effect was observed between different treatments at a depth of 10-20 cm. Minimum tillage in the pre-irrigation and post-irrigation stages has the highest moisture content. Conventional tillage disturbs the soil more than minimum tillage, increasing pores and unevenness of the soil surface, thereby increasing surface evaporation. Planting pattern had the highest moisture content and over plastic planting pattern had the lowest moisture content. Plastic cover is a barrier that prevents soil water from evaporating and keeps the root zone moisture regime at more stable levels, thus reducing the need for irrigation and preventing physiological disorders related to nutrients and water. There is no significant difference between tillage factor in two levels of conventional and low tillage and only planting pattern at 1% level has a significant difference. Different planting patterns significantly affected strawberry yield. According to the comparison of the average, the highest yield was related to the planting pattern on plastic and the lowest was obtained on the planting pattern without plastic. Since the yield of strawberries in different tillage methods was not significantly different and in this study the same amount of water was used in different methods. Therefore, tillage methods had no significant effect on strawberry water productivity.

The data was shown that the use of conservation tillage and plasticulture increased soil moisture retention by 22% which is due to the prevention of evaporation of soil moisture by Plastic mulch and Plant residue cover and less soil disturbance in conservation tillage. Conservation tillage has no significant effect on strawberry yield due to the slow trend in changing soil properties, but plastic mulch increased strawberry yield by 31.71% due to the increase in soil moisture retention. Since the type of tillage did not have a significant effect on strawberry yield in this study, therefore, tillage does not have a significant effect on water use efficiency, but different planting patterns, due to affecting yield, significantly increase water use efficiency here.