(B) Jiaodong Peninsula water-saving agriculture development model

Jiaodong Peninsula can be roughly divided into coastal plain area, low hilly area and piedmont plain area according to topography. There are great differences in topography, water conservancy projects and crop planting in different regions. Coastal plain areas are concentrated in cities and developed in economy, and agricultural cultivation is mainly based on facility agriculture and efficient cash crops. Competition for industrial, agricultural and domestic water is prominent, there are few surface water storage projects, lack of surface water resources, and serious over-exploitation of groundwater, resulting in seawater intrusion area of more than 1 000 km2; Mountains, hills and valleys crisscross in hilly areas, and surface water is mainly stored by reservoirs and ponds. Large and medium-sized reservoirs have also turned to urban water supply, and the irrigation canal system has low engineering standards, aging and degradation, and the main crops in hilly areas are mostly fruit trees; The piedmont alluvial plain has a small basin area, few water storage projects and low availability of surface water. The main water sources are shallow wells, large wells, small ponds and rivers. Agricultural water can only rely on scattered water sources, and crops are mainly grain, vegetables and facility agriculture. The natural geography and economic conditions of Jiaodong Peninsula determine that Jiaodong Peninsula must develop high-tech agriculture, high-standard water-saving projects, implement large-scale planting and modern management, and its water-saving agriculture development model can be summarized as follows.

1) Make full use of surface water, realize joint dispatching of surface water and groundwater, and optimize the allocation of water resources. Underground dams will be built in the lower reaches of Dagu River in Qingdao, Dagujia River in Yantai, Huang Shuihe in Longkou and Wanghe River in Laizhou to form underground reservoirs. Seepage wells were arranged on both banks of the river, and the efforts to replenish groundwater on both banks were intensified. The effect of supplementing groundwater is obvious, and the groundwater level is obviously improved, forming an engineering model of combining wells and canals to ensure abundant water and diverting water from rivers. In the piedmont plain area, a small water storage project is built on the river channel to connect scattered small water sources to achieve the purpose of joint regulation of surface water and groundwater. Yang Ting Demonstration Zone in Huancui District of Weihai City has centralized control of decentralized water sources through networking, rationally regulated water sources, and expanded irrigation area. Make full use of reservoirs and ponds in hilly areas, build gravity irrigation projects, and develop sprinkler irrigation and micro-irrigation by using natural head according to different zoning pressures.

2) Develop efficient agriculture and implement water-saving projects in a large scale, standardization and industrialization. Micro-spray and drip irrigation are used for fruit trees in mountainous and hilly areas, and high-efficiency crops such as protected agriculture and flowers in coastal plain areas gradually replace the traditional planting methods of bulk grain fields to realize industrial production. At present, agricultural science and technology demonstration parks and modern water-saving demonstration zones have been built in all urban areas of Jiaodong Peninsula, forming a good combination of large-scale planting and large-scale and standardized construction of water-saving projects. The development of efficient agriculture has promoted the improvement of water-saving engineering standards. In Weihai National "863" Plan Demonstration Zone, the original grain field has been planted with fruit trees by big contractors. Large industrialized planters in Longkou City, such as greenhouse vegetable greenhouses with an area of over 6.7hm2, greenhouse flowers with an area of over 3.3hm2 and persimmon orchards with an area of over 67hm2, adopted standardized drip irrigation and micro-spraying, realized automatic management, and implemented precise irrigation according to crop growth environment, which provided a demonstration for the large-scale development of "two high and one excellent" water-saving agriculture in this area and promoted the rapid development of efficient agriculture in this area.

3) Intensify the adjustment of agricultural structure, and vigorously promote agricultural water-saving technology. In the coastal plain, the measures to prevent groundwater overexploitation are as follows: first, limit groundwater exploitation; Second, increase the adjustment of agricultural planting structure and select excellent drought-tolerant varieties. Laizhou City, Longkou City and other seawater intrusion areas have reduced the planting area of grain crops and promoted drought-tolerant and salt-tolerant varieties, and achieved good results. Peanuts are all covered with plastic film, and fruit trees are covered with straw. For crops such as vegetables, biological drought-resistant agents should be sprayed to change the traditional irrigation system and reduce irrigation times. Agronomic water-saving measures have reduced crop transpiration and inter-tree evaporation, especially in coastal areas.

4) Change management mechanism, improve agricultural water-saving management level and realize modern management. Whether water-saving agriculture can develop steadily and play its benefits depends on its operation management mechanism and management level. For an efficient agricultural area, it is not enough to have high-standard water-saving projects, but also to have corresponding operation mechanism and management level. In the past, water-saving management was limited to the general extensive management level, and water-saving projects could not be maintained and could not play a long-term role. In recent years. Before the construction of water-saving projects in various areas of the peninsula, the project property rights were defined, and the project construction and management were unified. For example, all the facilities and water sources of water-saving projects in large contractors are clearly the property rights of the contractors, which are managed by the contractors, and the contractors invest in proportion in the project construction. The water-saving project with the village as the collective is clearly managed by the village. Village-to-village joint household projects are organized by township farmers' water associations. In management, modern automatic control technology is applied to improve the management level, adjust measures to local conditions, control the irrigation amount according to the water demand of different crops, and achieve the purpose of precise irrigation.

To sum up, the development model of water-saving agriculture in Jiaodong Peninsula can be summarized as follows: in view of the shortage of local available water resources, fully develop and utilize surface water, build river cascade impoundment project and groundwater recharge project, connect irrigation water sources, form joint regulation of surface water and groundwater, optimize the allocation and integrated application of cutting-edge technologies of water-saving agriculture, develop high-efficiency agriculture such as large-scale facility agriculture and characteristic agriculture, and build standardized water-saving projects and automation suitable for high-efficiency agriculture. Pay full attention to the adjustment of agricultural structure, vigorously promote agronomic water-saving technologies such as drought-tolerant varieties, straw mulching technology and biological drought-resistant technology in coastal areas, intensify the transformation of operation and management mechanism, clarify the property rights of water-saving projects, reasonably determine water prices, establish a high-level professional management team, make full use of automation technology to improve the operation and management level, and realize the optimal allocation of water resources in the peninsula.