QZ泵与框架式泵室在排灌工程中的设计与应用

QZ泵是传统泵型的更新换代产品，最大优点是效率较高并可以实现远程控制，对于安装和吊装维修具有传统水泵不可比拟的优越性，是中小型泵站向现代化方向发展的有效途径；框架式泵室具有结构新颖，受力合理，造价低廉，轻巧美观的特点，与传统的泵室比较可以大大节约土建工程量，二者有机结合，应用于排灌工程中，可以实现工程的优化设计，达到节约，高效的目的，普遍适用于平原圩区低扬程排涝与灌溉的水利工程。     

Optimization of yield and water-use of different cropping systems for sustainable groundwater use in North China Plain

A groundwater crisis is going on in the North China Plain (NCP), due to the excessive water consumption of the traditional winter wheat (WW)/summer maize (SM) double cropping system (two harvests in one year). In order to improve the water use efficiency in this particular cropping system and to evaluate the sustainability of water usage in Chinese agroecosystems, two field experiments were conducted from October 2004 to September 2006 at two sites of the North China Plain. The field experiments included four treatments: (1) farmers’ practice (FP) with two harvests in one year (WW/SM rotation), (2) FP with reduced input (RI) of water and nitrogen (WW/SM rotation), (3) three harvests in two years (TW, 1st year: WW/SM; 2nd year: spring maize), and (4) continuous spring-maize monoculture (CS) with one harvest per year (spring maize). In the treatments RI, TW and CS, the amount and timing of irrigation and nitrogen fertilization was optimized using TDR based soil moisture measurements and the N_min-method, respectively. Data showed that the utilization efficiency of irrigation water can be improved by optimizing soil water management compared to the traditional water management (FP). However, the groundwater net consumption required for RI still surpassed 300 mm yr⁻¹. Both FP and RI, still overused groundwater resources. The groundwater consumption in the continuous spring maize (CS) was on average 139 mm yr⁻¹. Therefore, the CS system can show the potential to use groundwater sustainably in the long term. Water usage of the TW treatment was in between the water usage of the other treatments. The grain yields in the double cropping systems (FP and RI) were higher than that in the two other systems (TW and CS). But the CS treatment showed the higher W_UE than others.