Arid Regions Strain Cropping Systems In Ningnan Mechanism And Technology System Build

iv Mechanism and Technological Setup of Flexible Cropping in the Dry-farming Region of South Ningxia WANG Long-chang (Northwest Sd-tech Universliy ofAgriculture and Fornb~ Tangling, Shaanxi 712100) Abstract Dry-land agriculture takes a much important place in the agricultural production in China and all over the world. As the population increases, and the situation of food shortage, water resource crisis and environmental deterioration faced by human beings become more and more serious, high attention has been paid to the development of dry-land agriculture in the countries in arid regions, and much progress has been achieved in the research of dry-land farming system. South Nlngxia is located at the northwest pert of Loose Plateau where is a hilly and gully area at the middle reaches of Yellow River and dry-land amounts to 90% of the total farmland. The climate in this region is typical continental one with an average annual precipitation of 250-600mm. According to the nationwide climate zone division, this region covers the semi-arid zone prone to drought, the semi-arid zone and the semi-humid zone prone to drought. Since the rainfall is limited in amount, uneven in seasonal distribution, strongly changeable among years, and water and soil erosion is serious, drought often affects agriculture of this region, which causes the low and unstable crop productivity, the low grain self-sufficiency, the backward rural economy and the bad farmers?living condition. So it is a poverty-stricken region being financially supported by the state with emphasis. Furthermore, as a result of the heavy population stress, the lands have been reclaimed blindly and the area of forestzy and grassland have been decreased during a long historic period. So the ecological environments have been badly destroyed and the contradiction of population梤esourco-梕nvironment has been increasingly intensified, which is detrimental to the sustainable development of agricultural production. In view of the trends that water circulation becomes seriously hindered, the scale of arid region becomes enlarged and the drought savage becomes exacerbated, to set up a cropping system that is adaptable to the rainfall resource situation and favorable to the raise of water use efficiency is the basic prerequisite to fully exploit the rainfall productive potential and to realize sustainable development of agriculture in dry-land regions. Aimed at the situation that the state government has made the strategic decision to exploit the west part and to reestablish a beautiful environment in the northwest regions, it has become an urgent problem to be solved in the dry-land regions including south Ningxia that how to realize the continuous increase of agricultural output and economic benefit by optimizing the cropping system while returning parts of farmland into forestry and grassland and adjusting agricultural structure. V Considering the current situation that rainfall is limited, drought occurs frequently, agricultural production is low and unstable, and productive benefit is low in the dry-land region of south Ningxia, this research has been conducted to set up an optimized flexible cropping decision system being adaptable to the arid climate in different areas and to establish a dro...