| Agricultural production on the northern slope of the Tianshan mountain range is limited by a shortage of water resources.There is not enough water to meet the needs of both cotton and grain crops in the region.More effective use of light,water,and heat resources could increase crop yields and promote sustainable agricultural and economic development in the region.These results are important for national food security and social stability.The objective of this study was to increase understanding about the suitability of using double cropping practices along with drip irrigation on the northern slope of the Tianshan Mountain Range.The spatial distribution of light,water,and heat resources was analyzed.The results were then used to analyze the effects of light,temperature,and climate on the photosynthetic potential of three double cropping systems and to determine what factors limited yield.Both the unique characteristics of the region’s natural resources and the growth demands of the crops were used to choose indicators for evaluating the suitability of the three double cropping systems.The double cropping systems were evaluated using both traditional fuzzy comprehensive evaluation method and a projection pursuit model based on real coding accelerating genetic algorithm(RAGA-PPC).The results of the two evaluation methods were compared and the most effective method was chosen for the final evaluation of the double cropping systems.Maps were created showing the northern slope of the Tianshan Mountain Range.The maps divided the region into different categories according to its suitability for each double cropping system.This information was combined with the economic benefit of the double cropping systems to create a final map of recommended land uses.The following conclusions were obtained from this study.(1)The variation characteristics of natural resources on the northern slope of the Tianshan mountain: The distribution of high consistency in the northern slope of Tianshan mountains area,frost-free period,accumulated temperature and single crop growth period the spatial,Annual accumulated temperature change trend consistent showed an increasing tendency.In addition,the light is rich in resources,double cropping growth model is not restricted.For each crop growth period in double cropping patterns of natural resources spatial distribution were studied.The heat resources in winter wheat space distribution characteristics of Wen Quan county for winter wheat growing period temperature slants little,in winter wheat growth required temperature of the bottom line,1733.7℃,Increase gradually to the east,Jing He,shihezi,Qi Tai along the accumulated temperature is higher,to meet the early winter wheat growth and development needs,and the remaining temperature can be rebroadcast,to better implement the two early variety collocation in the double cropping as the mode of planting;Qitai to east of Mulei County accumulated slightly lower than Qitai,but also can satisfy the precocious cultivars of winter wheat growth,but the harvest of late,but the harvest is late,can not be re-broadcast.Multicasting crop growth period ≥5 oC and ≥10 ℃ accumulated temperature spatial distribution of : Most area of the northern slope of Tianshan Mountains in the East and West ends of Wen Quan county,Mulei County and Qitai County after wheat harvest less accumulative temperature,To the middle of gradually increased,and reached the highest in Shawan county,Kuitun city and other regional.(2)Research about the yield potential of drip irrigation crop double cropping systems on the slope of Tianshan mountain: Using the mechanism method,as a model crop for one year and two by using meteorological data in Recent 48 years of photosynthesis production potential,the light temperature potential productivity,climate production potential of the temporal and spatial variation characteristics and resource utilization rate and practical resources production efficiency were studied,proven along North on the northern slope of Tianshan Mountains area "year two" planting area two a year as a model of high yield limiting factor,that heat is "double cropping," planting patterns and high yield potential of the main limiting factor.By selecting two early varieties,reasonable collocation of no tillage direct seeding,mulching increased temperature and other measures to reduce agricultural consumption,increase the temperature to improve.The current production of "double cropping" planting model of irrigation average coefficient of not more than 0.6,water is also "double cropping" one of the limiting factors of high yield and high efficiency pattern,needs to improve,increase the amount of irrigation.(3)The establishment of evaluation index system:Indicators were selected to evaluate the resource requirements of double cropping systems on the northern slope of Tianshan Mountains Range.These indicators were used in combination with previous research results and practical field experience to evaluate the double cropping systems.Both layer analysis and Delphi methods to make a second choice.Both methods included five times integrated scoring,demonstration,and analysis.To evaluate the drip-irrigated double cropping systems,18 evaluation indexes were selected related to the following four aspects: meteorological conditions,economic benefits,ecological benefits and social benefits.The evaluation indexes were scored and weighted according to their importance.The 18 indices were standardized and then their membership value functions were made.Finally,a model was proposed to evaluate the overall suitability of the double cropping system.(4)The suitability evaluation of drip irrigation crop double cropping system and regionalization on the northern slope of the Tianshan mountain:After the degree of membership of evaluation indexes is calculated through membership functions,single index is evaluated.Based on it the climate suitability of one crop in double cropping system is evaluated by fuzzy synthetic evaluation method and PPC model based on RAGA,and then the suitability of the whole system is deal with by the same methods.Finally,the different results are compared to each other to choose the better one for suitability evaluation.The results showed that,fuzzy comprehensive evaluation method combination with AHP method was the best one to evaluate the climate suitability of winter wheat-silage corn pattern.Meanwhile,fuzzy comprehensive evaluation method combination with the weights from RAGA-PPC was better for the climate evaluation of double cropping with soybean or oil sunflower.And the former was better for the comprehensive evaluation of wheat-silage corn,wheat-soybean and wheat-oil sunflower.Therefore,different evaluation methods were compared to see which was better for different double cropping systems and aims.According to double cropping model of comprehensive suitability evaluation results,Suitability rank first,the principle of economic benefit maximization of three kinds of double cropping pattern has carried on the comprehensive regionalization.However,results has a certain timeliness,regulated by market demand for agricultural products and supporting technology and policy.(5)Decision system developed and verified:The above results were used to design a resource information management system for the evaluation of the double cropping system and the management of natural resources on the northern slopeee of the Tianshan Mountain Range.The comprehensive design consisted of five parts,including double cropping model base,basic resource database,evaluation index database,suitability evaluation model base and decision support system.The programming language of the system is Java.The databases were developed and the system pilot ran and then verified preliminarily.Overall,analysis of the regional resources and the resource requirements of the double cropping systems were used to establish an evaluation index and an optimization model.The results indicated that heat units,but not light,limit yields in the double cropping systems on the northern slope of the Tianshan Mountain Range.The research not only has significance for selecting the best cropping system for each area,but also provides pioneering theories for addition research about double cropping systems. |
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