基于GIS和迈阿密模型的全球灌溉需水量计算

Calculation of global irrigation water demand basedon GIS and Miami model

通过计算光温生产潜力、气候生产潜力、光温潜力需水量、灌溉需水量以及衍生的可持续垦殖率指标,以解决农业生产潜力、农田熟制、灌溉定额、宜农荒地垦殖适宜性评价等农业发展问题。以迈阿密模型为理论基础,利用GIS空间分析的研究方法,计算出了上述指标的高精度全球分布场,得出全球光温生产潜力为2 260×10^8 t干物质,气候生产潜力为1 253×10^8 t干物质,灌溉需水量总计为12 441 km^3 。主要结论有:热带雨林区除外,全球气候生产潜力高值区同当前农业区高度吻合,表明农田气候潜力已经被人类充分利用;在温带地区,可持续覆膜雨养垦殖率>2/3的地区适宜开垦宜农荒地,发展雨养农业。根据迈阿密模型计算得出的灌溉需水量可作为制定农田喷灌定额的重要依据;覆膜滴灌节水效果最佳,可持续覆膜滴灌垦殖率为各种垦殖率中最大值,可作为指导宜农荒地资源开发和多熟制农业发展的主要指标。

The main purpose of this paper is to solve the problems of agricultural development, such as agricultural production potential, farmland ripening system, irrigation quota, and evaluation of the reclamation suitability of agricultural wasteland, by calculating light-temperature production potential, climate production potential, light-temperature potential’s water demand, irrigation water demand, and derived sustainable reclamation indexes.Based on the Miami model and GIS spatial analysis, the high precision global distribution field of the above indicators was calculated.The global light-temperature production potential was 226.0 billion tons of dry matter;the climate production potential was 125.3 billion tons of dry matter;and the total irrigation water demand was 12 441 cubic kilometers.The main conclusions were as follows: except for tropical rainforest areas, the high value regions of global climate productivity are highly consistent with the current agricultural areas, indicating that the climate potential of farmland was fully utilized by human beings;reclaiming suitable agricultural wasteland to develop rainfed agriculture in temperate regions generally required the local sustainable reclamation rate of film-mulched rainfed agriculture to be more than 2/3;the irrigation water requirement calculated according to Miami model can be used as an important basis for formulating the quota of sprinkler irrigation in farmland;and the sustainable reclamation rate of film-mulched drip irrigation is the highest among all kinds of reclamation rates, which can be used as the main index to guide the exploitation of wasteland resources suitable for agriculture and multi-cropping potential in agriculture.