Study On Resource-saving Cropping Systems In Northern Region Of Huang-huai-hai Plain

Huang-huai-hai Plain was the typical area of benefit conflicts on agricultural production in China. Whether the limited water and fertilizer and arable land resources in this area could be sustainable utilization or not was directly related to the sustainable development of national agriculture. Developing resource-saving farming system technology in this area and in China was the important way to got highly-efficient use of agricultural resources and ensure food security. So, from the view of resource efficient utilization and sustainable development, the field experiment researches to obtain different crop growth parameters in typical regions of Huang-huai-hai Plain were imperative. These works could provide us with the theoretical and practical basis to explore resource-saving and highly-efficient use farming systems in this area to construct the resource-saving farming systems and technical systems.The experimental base, was located in Wuqiao County, Hebei Province. We regarded the resource-saving and highly-efficient use farming system as the primary content to study the effects of different water-saving, fertilizer-saving and water-fertilizer-saving modes on the crop growth, yield, water consumption, water and fertilizer use efficiency of winter wheat-summer maize. Also we studied different crops yield, resource utilization and economic benefits of different cropping systems. Our purpose was to choose the optimal water-saving modes, fertilizer-saving modes and cropping systems whose relative benefits were best to fit for local production. The main results were as follows:1. The water-saving irrigation experiments results indicated that: (1) With the three irrigation modes, the soil water consumption in winter wheat season decreased with increasing irrigation amounts, while water consumption in summer maize season increased with the increasing irrigation amounts of winter wheat season. The increment of the annual yield of winter wheat-summer maize with rrigation mode W2 (irrigated before sowing and at jointing stage: 75mm+90mm) and W3 (irrigated before sowing, at jointing stage and at filling stage: 75mm+90mm+60mm) was 8.7% and 12.5% higher than that with W1(irrigated before sowing: 75mm), respectively. The WUE of winter wheat with the irrigation mode W2 was 11.1% higher than that with W3, but the WUE of summer maize had less difference between irrigation modes W2 and W3. The annual WUE (WUET) of W2 and W1 was 21.28 kg·mm·hm^-2 and 21.60 kg/mm/hm², being 7.8% and 9.4% higher than that of W3, respectively. Considering the annual yield, water consumption and WUE, irrigation mode W2 could be the advisable mode for water-saving and high-yielding. (2) There was different water-saving potential between winter wheat varieties. The results show that the yields of Shimai15 (T2) were higher than that of Jimai22 (T1) under three irrigation modes. The WUE of T22 was the highest one which was up to 20.22 kg/mm/hm², and it was 21.9% higher than that of T12 and 7.4% higher than that of T13. It was very clear that Shimai15 had water-saving and higher yield advantages. The water-saving irrigation experiments showed that combining suitable varieties and optimized irrigation modes were helpful for saving water and increasing yield in northern region of Huang-huai-hai Plain which was short of water resources.2. The tests of fertilizer-saving modes experiments results indicated that: (1) With the fertilizer-saving modes 1 (FS1: The N , P₂O₅, K₂O applied to winter wheat and summer maize were all 157.5kg/hm²,138kg/hm²,112.5kg/hm²),winter wheat grew well and its yield was 7897.6kg/hm² which was significantly higher than other four fertilizer modes. The WUE of FS1 of winter wheat was the highest one which is respectively 57.7%, 43.9%, 27.0% higher than CK (without fertilizer) in Grain WUE, Biological WUE, WUEI. The N physiological efficiency, Nitrogen partial productivity and Nitrogen agronomic efficiency of FS1 were relatively higher and the results suggested that fertilizer modes FS1 was better in improving the nitrogenous fertilizer effect of winter wheat. (2) The annual yield of winter wheat-summer maize of FS1 was higher than other four fertilizer modes. The increase rate of annual yield of FS1 was the largest. The Grain WUE of FS1 was the highest one. The integrated effect of FS1 was better than the other four modes considering the changes of soil nutrient content in topsoil. The fertilizer modes FS1 ensured the high yield and high water-fertilizer use efficiency of winter wheat-summer maize system and it improved the soil nutrient content, so its benefits were outstanding.3. The water and fertilizer modes experiments results indicated that: (1) With five water and fertilizer modes which were represent by A, B, C, D, E respectively, the annual yield of winter wheat-summer maize were A>D>B>C>E.The annual yield of A, D, B, C were respectively 23.3%, 11.34%, 8.04%, 6.19% higher than that of E. (2) The total water consumption of winter wheat-summer maize increased with increasing irrigation amount of winter wheat. The water consumption of A was the highest up to 938.82mm and it was 129.9mm higher than that of D. The annual Grain WUE of D was the highest one which was up to 22.57kg/mm/hm². The annual Grain WUE of D was respectively10.5%, 13.4%, 8.7%, 13.9% higher than that of A, B, C, E. The results indicate the mode B irrigated"Regreening stage irrigation water"just increased the total water consumption with little to increase yield and WUE. (3) The annual N physiological efficiency of five modes were nearly equal but the mode D was slightly higher than the other modes. The annual nitrogen partial productivity were D>C >E >A>B. These results showed the nitrogen fertilizer evaluation effects of D, C are better than A, B, E while the effect of D even better than C. Considering economic benefit and water-saving effect, the mode D (The winter wheat was irrigated and fertilized before sowing and at jointing stage, the summer maize was fertilized before sowing and at jointing stage) which was input less water and fertilizer was the better mode of high water and nitrogen use efficiency.4. The planting modes experiments results indicated that: (1) The average yield of double cropping systems were more than that of three crops in two years and cotton sole cropping. In two years, the total yield of winter wheat-summer maize was significantly higher than other cropping systems. (2) In two-year rotation circle, the total water consumption of double cropping systems were more than that of sole cropping and more than that of three crops in two years. Analysing the WUE of two years, the total WUE of winter wheat-summer maize was the highest one which was up to 18.0kg/mm/hm², spring maize→wheat-maize was next up to 16.6 kg/mm/hm². (3) The economic benefits of cotton sole cropping and winter wheat-summer maize double cropping system were better from the perspective of using water more efficiently. (4)In two years, the ratio of outputs to inputs of cotton were the highest one which was uo to 2.71 and that of spring maize→wheat-maize and winter wheat-summer were higher than other planting modes. Also, the net benefits of the three modes were higher. (5) The synthetical analysis results indicated that winter wheat-summer maize, spring maize→wheat-maize and cotton were suitable to be planted in study region while the other four planting modes should be reduced. Considering the fact of severe water shortages in study region, the mode spring maize→wheat-maize could be the best planting mode in the futher because its total water consumption in two years was 257.3mm less than that of winter wheat-summer maize.