The Experimental Study On Furrow Irrigation Pattern Of Corn In Semi-Arid Region Of Western Heilongjiang Province

The semiarid region of western Heilongjiang province is an important grain production base in China. However, in the area, average annual rainfall is few and the shortage of water resources is very serious. Due to the underdevelopment of economy, traditional surface irrigations such as border and furrow irrigation are still taken as the dominant way in farmland irrigation, which leads to the great waste of water resources. In recent years, some specialists and scholars proposed a new irrigation technology of alternate interval furrow irrigation. The study of this new water一svaing irrigation technology in the northwest of China is mature but very few in Heilongjiang province even in the Northeast. In order to explore the suitable of alternate interval furrow irrigation in Heilongjiang province, aiming at some practical problems including more wind, less rain, lower food production and crop water use efficiency, etc, in semi-arid region of western Heilongjiang province, the experiments of the effects of different water levels under the three irrigation methods which were conventional irrigation, alternate interval furrow irrigation and fixed interval furrow irrigation were conducted in DuMeng county, Heilongjiang province to study the influences of the different irrigation methods with different water levels on the corn's growth, yield and water use efficiency, which could provide the necessary theoretical technological supports for local development of water-saving agriculture. The main conclusions were as follows:(1)Comparing the deep soil water content, conventional irrigation raised slowly between 80 to 100 ground, fixed interval furrow irrigation changed not obviously, and alternate interval furrow irrigation kept steady basically. Water of conventional irrigation moved vertically, alternate interval furrow irrigation and fixed interval furrow irrigation had vertical and side mocement which could reduce the deep seepage of soil water.(2)Under the same water supply, water consumption of different irrigation methods had difference but not marked. Under the same irrigation method and different water levels, water consumption and diurnal water consumption increased in the wake of raising water supply. At the whole growth stage, diurnal water consumption of conventional irrigation was higher than others.(3)Watering-side roots of alternate interval furrow irrigation and fixed interval furrow irrigation were in wet environment, another side was in dry environment. Controlling roots'moisture condition of different areas, roots undergo drought hardening of certain extent. Appropriate water lack could promote dry matter accumulation of above-ground. The results showed that situation of corn's leaf area, plant height, stem perimeter, dry matter accumulation and root growth under interval furrow irrigation was similar compared with conventional irrigation, even better under appropriate water lack. Under serious water lack, the growth of corn was worse than others.(4)Photosynthetic rate of alternate interval furrow irrigation and fixed interval furrow irrigation were lower than conventional irrigation in the earlier growth stage under the same water lever. In the later stage, fixed interval furrow irrigation was still lower, but photosynthetic rate of alternate interval furrow irrigation approached even exceeded that under conventional irrigation. Compared with photosynthetic rate, the reduction range of transpiration rate of alternate interval furrow irrigation and fixed interval furrow irrigation were higher than conventional irrigation. In the same irrigation method, corn's photosynthetic rate and transpiration rate of different stages reduced evidently along with the water volume's reduction, especially water stress was serious. Water use efficiency rested with Pn and Tr's relative change.(5)Along with water supply's reduction, the grain number per ear decreased. In the same water level, alternate interval furrow irrigation had an advantage in the grain number, and fixed interval furrow irrigation had the inferiority. Yield-increasing effect of different irrigation treatments mainly depended on the increase of corn's 100-seed weight. The grain yeild difference under the same irrigation treatment and different water levels was marked, especially declined under serious water lack. The results showed that WUE under appropriate water lack was highest, especially treatment of alternate interval furrow irrigation. It's water supply reduced 29 pecent combined with conventional irrigation, meanwhile, the yield raised 4.93 pecent and WUE increased 29.9 pecent. Alternate interval furrow irrigation could also ensure grain yeild and improve WUE when reducing water supply properly.(6)The article used two evaluate methods which were projection pursuit classification model based on RAGA and the grey correlation analysis based on the entropy to analyse the corn's furrow irrigation models, finally gained the best irrigation model which was alternate interval furrow irrigation under appropriate water lack. This model's water supply reduced 29 pecent, but it's WUE was highest among all the treatments, meanwhile obtained highest yield and net income.