Land Evaluation and Suitability
Sina Bigdeli; Heidar Ghafari; Mojtaba Norouzi Masir; Abdolamir Moezzi
Abstract
Introduction: Today, the concept of soil quality (SQ) has been widely used to know the capacity and limitations of soils in different environmental systems. The degree of suitability of land is determined by its capacity to provide services and its flexibility against external conditions. Production ...
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Introduction: Today, the concept of soil quality (SQ) has been widely used to know the capacity and limitations of soils in different environmental systems. The degree of suitability of land is determined by its capacity to provide services and its flexibility against external conditions. Production of plant biomass is one of the most important functions of soil in relation to food security. The share of dry land in Iran's agricultural production, especially wheat, is very significant. So that in terms of area, about half of the total area of agricultural lands, in terms of volume of production, about 10% of all agricultural products and about 30% of the country's wheat production are related to these lands. Therefore, maintaining the soil quality of these lands is very important. The main goal of this research is to model and quantify the soil quality of part of the rainfed agricultural lands of Dezpart city using integrated multivariate analysis and also to determine the minimum effective data set.Materials and methods: This study was carried out in a part of the rainfed agricultural area of Dezpart County. First, 119 soil samples were prepared using the composite method from the soil depth of 0-30 cm. Soil sampling was done in a stratified random manner to include all the different geomorphological units. The geographic location of the sampling points was also recorded. The samples were transferred to the laboratory and their chemical-fertility and physical characteristics include reaction (pH), electrical conductivity (EC), organic matter (OM), total nitrogen, available potassium, absorbable phosphorus, calcium carbonate equivalent (CCE), texture, bulk density, mean weight diameter (MWD) of soil aggregates, soil gravel content and cation exchange capacity (CEC) were measured. Then the soil quality was determined using two datasets of total (TDS) and minimum (MDS), and multivariate analysis method. In this method, by using appropriate scoring functions, a score between zero and one was considered for each member of the data set. Also, a weight coefficient was calculated for each member, and finally, the soil quality index, which indicates its degree of desirability, was obtained by three indices including Nemero (NQI), cumulative weighted index (IQI) and simple cumulative index (AQI). Finally, a spatial variation map of soil quality was prepared using the Inverse Distance Weighting (IDW) method in geographic information system (GIS) software.Results and Discussion: The results of the principal component analysis (PCA) test indicated that there are three main components that cover 78% of the total variance changes. The first component alone accounts for about 41% and the second and third components account for 25% and 12% of the total data variance, respectively. Based on the correlation analysis between soil components and characteristics, five characteristics including organic matter (OM), silt content, gravel, pH and EC were selected as MDS members. Became in the TDS collection, the highest weights related to silt and sand (0.093 and 0.095, respectively) and the lowest weight with 0.050 was assigned to bulk density (BD). In the MDS set, the highest weight was related to organic matter and silt and the lowest weight was related to pH. The soil quality of the region was generally classified as medium based on the two indexes of AQI and WQI. However, the NQI method indicated that the soil quality was low. Among the three selected indices with different functions and data sets, the weighted soil quality index with the minimum data set and nonlinear function (WQI_MDS_NL) was chosen as the superior model due to having a higher sensitivity index (or a larger standard deviation). The spatial soil quality map, which was prepared for this study, showed that approximately 50% of the lands in the region had an average soil quality and 50% had a low soil quality.Conclusion: Organic matter, silt, pH, gravel and EC are the main characteristics to determine the soil quality of the region. In addition, stability of soil aggregates, bulk density and lime are the most important limiting factors of soil quality in the region. Therefore, it is suggested to use appropriate management practices such as conservation tillage and use of organic fertilizers to improve these characteristics.
Ahmad Daneshkhah; Mahmoud Ghasemi Nejad raeini; Mohammad Amin Asoodar; Afshin Marzban; Mokhtar Heidari
Abstract
AbstractIntroduction 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 ...
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AbstractIntroduction 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.Materials and Methods 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.Results and Discussion 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.Conclusion 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.
