| Water and nitrogen are the most important two factors for crop production in agriculture practice . Continuously, people paid close attention to the relationship between two factors . This research analysed the reason to low water use efficiency , low nitrogen fertilizer use efficiency in agricultural production practice and the main problem existing in the fertilizer application and water-saving measures at present deeply . The main aim was improving the water and nitrogen use efficiency in arid areas . Especially , in view of the problem of space dislocation of water and nutrient on soil profile in agricultural production in arid and semi-arid areas , we put forward a new water and nutrient modulating theory and technique creatively which was called hole-source . Compared with conventional fertilizer application pattern , the water and nitrogen transport and changing laws of hole-source technique was studied . At the same time , the final effects of two patterns were evaluated from many points of view. So a new train of thought about operating water and fertilizer reasonably in arid areas was put forward . The results showed that : 1. Compared with conventional fertilizer application pattern , soil infiltration capacity , water-conserving ability , water availability and water use efficiency under hole-source pattern were all increased to different degree . Water distribution on soil profile, especially the soil water distribution in root zone was more reasonable . Therefore , modulating function of soil reservoir could elaborate effectively . 2. There had obvious surface-gathering phenomenon of nitrogen distribution on soil profile under conventional pattern . But the unstability of soil water condition in surface soil layer must affect the uptaking and utility if nitrogen to a great extent . The hole-source technique avoided the happening of nitrogen surface-gathering and solved the problem of dislocation of water and nitrogen on soil profile through fertilizer's applicating in deep soil layer at point position . So water and nitrogen coordinated well on soil profile . 3. The water use efficiency and nitrogen fertilizer use efficiency of hole-source treatments were all higher than those of conventional pattern because of the modulating and controlling of water and nitrogen . And the different combination of hole depth and hole distance would affect the elaboration of modulating function greatly . Under the condition of this test , the treatment of hole distance and hole depth being 30 cm and 20 cm respectively required the highest water use efficiency and nitrogen use efficiency . 4. The results of nitrogen fertilizer residual effect under conventional and hole-source pattern showed that there had no significance difference on statistical analysis . 5. The hole-source technique decreased the volatilization of NH3 through N fertilizer' being applicated in deep soil layer .During this test stage, the NH3 accumulative loss amount of hole-source treatments was only 1/60~1/100 of that of conventional treatments. 6. The leaching amount of NO3--N was decreased through retarding the rate of nitrification and reduction the leaching areas . And the effect of decreasing NO3--N leaching of first season crop was better than that of second season crop , the earlier stage was better than later stage .7. Temperature and soil moisture could have important effect on volatilization of NH3 under two patterns . Under condition of this test , the relationship between volatilization amount of NH3 and temperature and soil moisture were all no linear correlation . There had the appropriate combination of two factors for the highest volatilization amount of NH3 under two patterns . The applying effect of this technique under different soil types , crop kinds , climate and hole stuff awaited more lucubration . |
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