جستجوی مقالات مرتبط با کلیدواژه « land suitability » در نشریات گروه « اکولوژی »

This study was conducted aimed to identify the potential of lands in Lorestan Province for the second cultivation of forage millet using Geographic Information System(GIS), Network Analysis Process(ANP) and fuzzy logic.In order to identify the potential of lands, first the raster layer of environmental factors affecting forage millet cultivation including the minimum, maximum and mean temperature, elevation, slope, pH, texture, organic matter, total nitrogen, potassium and phosphorus available in GIS was prepared. Then, using fuzzy functions, the map of each factor was standardized. The weight of each factor was determined by ANP. By combining the weighted layers, the final layers were produced and zoned into four highly suitable, suitable, marginally suitable and unsuitable classes based on fuzzy logic.The results showed that fuzzy value of agricultural lands for forage millet was between 0.35 and 0.88. The highest study area level belonged to the suitable class(60.42%) and the lowest study area level belonged to the highly suitable class(16.35%). Investigation of climatic suitability, topography and soil fertility maps showed that these factors caused severe limitations in 38.27, 38.15 and 7.44% of lands, respectively. Evaluation of climatic maps, topographic and soil factors showed that except for soil pH, all other factors in a part of the study area caused limitations for forage millet cultivation.Investigation of the land suitability final map showed that about 77% of the study area are highly suitable and suitable and cold regions, especially the east. Northeast of the province, are marginally suitable for forage millet double cropping.

Stochastical analysis can increase decision-making reliability, meanwhile increasing the flexibility of decisions. The critical role of climatic factors in land zoning on the one hand and the stochastical nature of climatic variables, on the other hand, causes the uncertainty of land suitability grading for plant cultivation, especially in dryland conditions. Golestan province has the third rank among the Iran provinces with about 400,000 hectares of cultivated land and production of more than one million tons of wheat, of which about 57 and 50 percent are allocated to rainfed cultivation, respectively. The present study was conducted to examine changes in various climate variables affecting wheat growth under the influence of different occurrence probabilities and zoning agricultural land in Golestan province for the rainfed wheat cultivation under these conditions.

 First, dates of planting and occurrence of each phenological stage of rainfed wheat were determined by daily data of precipitation and minimum and maximum temperatures for 33 weather stations in Golestan province in a 26-year typical statistical period. Then, by fitting different probability distribution functions and selecting the best distribution, the values of these variables were estimated at five occurrence probability levels of 25, 50, 75, 85, and 95 percent. Next, the average air temperature, the possibility of occurrence of adverse temperatures, precipitation and ratio of effective precipitation to potential evapotranspiration of wheat for each growth stage and total growth period were calculated for whole weather stations at different occurrence probability levels. Finally, by providing zoning maps of these variables and other features including elevation, land slope, land type, soil salinity and overlaying 22 layers for each occurrence probability level, agro-ecological zoning of agricultural lands of Golestan province for rainfed wheat cultivation at different occurrence probability levels was performed.

 Results showed that increasing occurrence probability level from 25 to 95 percent due to delaying suitable planting date from late autumn to early winter and its effect on the climatic-environmental conditions and the length of the plant growth stages improved the degree of land suitability grade for rainfed wheat cultivation in terms of mean air temperature in stages of flowering, maturity and total growth season, the occurrence possibility of temperatures higher than 14 and less than 9 °C in germination and flowering and maturity stages, respectively, and the amount of precipitation in the germination stage. Adversely, it resulted in degradation in the degree of land suitability in term of mean air temperature in the germination stage, the occurrence possibility of temperatures higher than 25 and 30 °C in flowering and maturity stages, respectively, and the amount of precipitation and ratio of effective precipitation to potential evapotranspiration in stages of flowering and maturity and the entire season. The results of agro-ecological zoning showed that the extent of suitable and moderate zones was between 50-56 and 44-50 percent of the agricultural land, respectively, for the occurrence probability levels of 50, 75 and 85 percent and the occurrence probability did not have a significant effect on zoning. In comparison, at the occurrence probability levels of 25 and 95 percent (equal to the early and late planting dates, respectively), about 91 and 78 percent of the province's agricultural land was located in a suitable and moderate zone, respectively. These results are accordant with the findings of Hoseini et al. (2018), who showed that the maximum extent of suitable land for cotton cultivation in Southern Khorasan province occurred in the early planting date. Considering the majority of agricultural land of Golestan province is located in the middle strip of the province, most changes of zoning maps by occurrence probability level have also occurred in this region.

A low reduction in cultivation risk (increasing the occurrence probability from 25 to 50 percent) significantly degraded the land suitability for rainfed wheat in Golestan province while more reduction in the farming risk (increasing the occurrence probability up to 85 percent) led to no significant effect on land suitability. However, if the minimum risk (95% probability) be selected as a management decision for rainfed wheat farming, the lowest land suitability for rainfed wheat cultivation will occur.

Growing demand for food in the coming decades will require a significant increase in crop production. Indeed, the variability of weather, soil and topography result in different agro-ecological conditions which may be suitable or unsuitable for some crops. To determine land suitability in an ecosystem, agro-ecological zonation is one of the effective tools for recognizing the capabilities of land and allocating them to the best and most profitable types of crop utilization. Currently, it is one of the most commonly used methods for determining the agro-ecological characteristics of large geographical areas for the production of crops. This research was performed to perform the agro-ecological zoning Shavoor area for the production of wheat. Therefore, this research was conducted with the aim of agro-ecological zoning and evaluate the land suitability in a part of Shavoor lands of Khouzestan, with using the parametric method (square root). Also, wheat potential production and potential land production were calculated.

Study area: The present study conducted in Shavoor area, Khouzestan Province, Iran, is located in 31° 47' 39" to 31° 53' 19" N latitude and 48° 27' 32" to 48° 22' 12" E longitude. The study area is 5000 ha. The length of the "growing season" or "growing period" (LGS or LGP), as defined by the Agro-Ecological Zones project, is the period (in days) during a year when precipitation exceeds half the potential evapotranspiration. A period required to evapotranspiration an assumed 100mm of water from excess precipitation stored in the soil profile is sometimes added. No provision made for stored soil moisture. To obtain a length of the growth period, the rain, and potential evapotranspiration during the growth period estimated from the data weather of Safiabad station. For soil mapping, it was used for precise semi-detail studies irrigation and drain networks of Shavoor plain. Finally, the soil map prepared. Landsat 8 and IRS satellite images in 2016 were used to provide a land-use map. The agro-ecological zoning map of the study area was obtained by the combination of agro-climatic and agro-edaphic data and apply the function in the GIS environment. To evaluate the Land suitability in Agro-ecological zoning, conformity of the land characteristics in each defined zone with wheat growing requirements performance, and the final class of land was measured. To estimate the Potential yield in the region, the FAO model, was used.

After overlapping desired maps in the GIS, the study area defined and separated into 8 Agro-ecological zones. Land suitability evaluation

Based on square root and Storie methods 42% and 58% of the land were located in the classes including moderately suitable land (S2) and marginally suitable (S3). The potential yield of wheat was obtained 6823 kg ha-1 by using the FAO method. The land production potential in each of the zones was also estimated. Because of the effects of the aforementioned limitation factors, the land potential production for wheat decreased in lands the Khalaf Aziz (A), Bam Dej (B), Elhaee (C), Ali Chaab (D), Karkheh (E), Abdul Khan (F), Sayed Abbass (G) and Bait Hatam (H) by 28, 60, 60, 60, 55, 52, 40 and 51%, respectively. By improving these constraints, such as proper management practices such as increasing organic matter to the soil and land leaching, it is possible to increase the production of wheat in these ecosystems.

This evaluation conducted to agroecological zoning of the Shavoor plain for agro-ecosystem planning. Land suitability and land production potential estimated in each zone for wheat-based on parametric (square root) and Storie method. The results showed that climatic properties did not create significant limitations for wheat cultivation in an ecosystem. Limitations related to soil properties results showed that the A and F zones of the study area were the moderately suitable class (S2). Also, the deficit of organic matter, salinity, and alkalinity in the other parts are the major limiting factors.

 

Undoubtedly, development of agricultural production systems without sufficient knowledge of the current situation and defining constraints is impossible. The potential of lands for cultivation of crops is determined by evaluation of biophysical and environmental variables. Therefore, climate, soil and geomorphologic environmental components are the most important agro-ecological variables for the evaluations. GIS is a powerful set of tools for collecting, storing, retrieving, transforming and displaying spatial data of the real world. Much progress has been made over the last twenty years in developing methods of multi criteria-land suitability evaluations, especially by integrating GIS with multi-criteria decision making (MCDM). From MCDM, the analytic hierarchy process (AHP) is one of the most common methods to determine criteria weights. The integration of GIS and AHP approach is a useful method for decision-making, suitable for analysis of a big amount of data with a new set, enabling to show them in the form of maps and shapes. The aim of this study was to investigate the potentiality of lands for cultivation of Canola and Wheat in order to increase the sustainable productivity of the crops in Maroon basin of Khuzestan province, Iran, using a GIS based approach.

The study area of this experiment is located in the Maroon basin of Khuzestan Province in South West Iran with hot and dry climatic conditions. This area contains nearly 30 percent of current agricultural lands in Khuzestan province. Relevant environment components such as soil properties (pH, EC, texture, organic matter), topography (Elevation and slope), climate factors (precipitation and temperature) and water resources potential for cultivation of canola and wheat at different spatial resolutions were considered, collected from scientific references and then classified. Afterwards, digital information layers for Wheat and Canola were prepared based on the growth parameters and available environmental conditions, with AHP weighting using GIS. Experts’ opinions were employed to determine the sufficient weights of each factors using relevant questionnaires. Finally, the generated agricultural land suitability maps were divided into 5 categories according to FAO classification guidelines as: highly suitable, suitable, moderately suitable, marginally suitable and not suitable.

The results of the research showed that among the factors contributing to land, the weightings of soil salinity and slope, with 0.2231 and 0.0254 were the highest and lowest limit, respectively. The weights are applied in overlapping layers of existing conditions using GIS software shows that an area of 632473 hectares of land in the basin Maroon, each year, and the different potential for canola and wheat crops. According to the agricultural land use suitability map, it was determined that 7.4% (46890 ha) of the studied area is highly suitable, 9.8% (62013 ha) suitable, 27.8% (175950 ha) moderately suitable, 29.4% (185434 ha) marginally suitable and 25.6% (162186 ha) not suitable for cultivation of wheat and canola. High soil salinity and limited water resources in the studied area were the most effective factors lowering the suitability of agricultural lands, in this study.

GIS is a powerful tool, as it provides many special features in a single system usable for land suitability. Generally, the goal of this study was to achieve some conclusions on the quality of land, decide on crop rotation and scheme for the management of the farms. This study were realized with the aid of GIS and AHP. It determined spatial highly suitable in Maroon basin district of Khuzestan province which help to sustainable agricultural production.
Acknowledgements
This study was supported by the Agricultural Research, Education and Extension Organization, Jehad Agricultural and Water and Power Authority of Khuzestan province. We acknowledge them for their assist

Land use suitability is the ability of a given type of land to support a defined use. The suitable areas for agricultural use are determined by evaluating the environmental components and understanding of local biophysical restraints. The topographic characteristics, climatic conditions and the soil quality of an area are the most important determinant parameters of land suitability evaluation (Almashkreki et al., 2011). Bhagat et al. (2009) analyzed land suitability for cereal production in Himachal Pradesh (India). In this study different parameters including climatic variables (precipitation and temperature), topographic (elevation), soil type and land cover/land use have been used in order to evaluate land suitability for cereals food-grain crops. The possibility of further expansion of cultivation area under each cereal crop was also determined. Golestan province is one of the most important region for crop production in Iran. In this study, geographical information system (GIS) and multi-criteria evaluation (MCE) were applied to evaluate the feasibility of agricultural lands in Aq-Qalla township for annual alfalfa (Medicago scutellata L. Mill.) cultivation. This research was conducted in northern part of Iran, Aq-Qalla township in Golestan province. The climate of this region is under the influence of Alborz Mountains, Caspian Sea, the southern wildernesses of Turkmenistan and forests. The suitability of current agricultural lands in Aq-Qalla township for annual alfalfa cultivation, were evaluated by matching the environmental requirements of crop and the land characteristics. For this purpose, required data and information of the study area were collected during 2013, and thematic maps were provided. Climatic data were collected from 43 weather stations located in Golestan province. The digital elevation model (DEM) dataset with a 40×40 m resolution and township boundary of the study area were obtained from Natural Resources Organization of Golestan province. The soil nutrient data were collected from 300 sampling sites distributed in Aq-Qala township, including EC, pH, Texture, N, P, K, Ca, Fe, Zn and Organic matter. Kriging and IDW methods were applied for interpolation of environmental variables. The digital environmental layers overlaid and integrated in GIS in respect to Analytical Hierarchy Process (AHP) weights. The weight of factors for feasibility were obtained from local experts, through a pairwise comparison of statistical analysis in Expert Choice software (ver. 2000). Zoning of lands carried out in four classes including: highly suitable (S1), suitable (S2), semi-suitable (S3) and non-suitable (NS). This system was based on matching between land qualities/characteristics and crop requirements. Highly suitable, suitable and semi-suitable lands were expected to have a crop yield of 80-100%, 60-80% and 40-60% of the yield under optimal conditions with practicable and economic inputs, respectively. Non-suitable lands were assumed to have severe limitations which could rarely or never be overcome by economic use of inputs or management practices (Ghaffari et al., 2000). Results of AHP questionnaires analysis showed that among the factors affecting land suitability, climate (0.559) and topography (0.113) criteria had the highest and least weight, respectively. In this AHP model inconsistency ratio is about 0.002. This indicates that the comparisons of criteria were perfectly consistent, and the relative weights were suitable for use in the land suitability analysis in Aq-Qala. The results showed that 23.1% and 47.2% of these areas were high suitable and suitable for alfalfa cropping, respectively. These zones had enough precipitation, suitable topography and high fertility. The semi-suitable and non- suitable regions (about 30% of area) were located in the northwest, east and south of Aq-Qalla township. In these zones, the environmental requirements of annual alfalfa were not fitted to ecological variables of agricultural land. The results showed that the topography and climatic characteristics (temperature and precipitation) of this region were suitable for annual alfalfa growth. In this study, the limiting factors were: high EC (about 30 dS.m-1), deficiency of organic matter, K and Ca. Therefore, analyzing the soil quality is essential for understanding the environmental degradation processes in the region. Proper land management practices, leaching, drainage, land preparation, crop rotation, specific irrigation methods and using resistant crop are helpful methods to increase crop yield in this area.

Optimal use of lands heavily relies on careful assessment of agro-ecological resources. Evaluation of potential lands for various cultivated crops is the first strategic priority to increase production and optimized use of resources. This present study was aimed to identify effective climatologic، topographic and soil-related factors on rainfed wheat cropping in Qaresoo basin of Golestan province and determination of suitable areas to produce this crops usings Geographical Information System (GIS) and Analytic Hierarchy Process (AHP). At first، ecological requirements of rainfed wheat was identified from scientific literatures and then were classified to provide thematic maps. In this study، minimum، average and maximum temperatures، precipitation، slope، aspect، elevation and EC were considered. The Analytical Hierarchy Process (AHP) was used to find weight of each factor. Finally، the maps were provided and overlaid in GIS media and afterward the zoning of areas for rainfed wheat cultivation was done. Results showed that wheat grown lands would be located in four suitability classes. About 5170 hectares (6%) of the agricultural areas and 3% of the total area of the Qaresoo basin were located in high suitable class for rainfed wheat cultivation. Suitable precipitation، lower slope and projecting to south slopes and also the desirable electrical conductivity were the reasons make these regions suitable. Also، results showed that about 909 hectares (1. 5%) of Qaresoo basin lands that now are cultivating by rainfed wheat، have not required potency to produce this crop.