Coupling Effect Of Water And Fertilizer With Spray Irrigation On Maize Yield In Semi-arid Region Of Heilongjiang Province

Heilongjiang is a major agricultural province in China, located in the semi arid and semi moist region of our country. Both water per capita and water per mu are below the national average. Issues in Heilongjiang province such as the severe drought in spring, uneven distribution of water requirement in different growth stages of crop and infertile soil due to unreasonable fertilization have caused the great limit of agriculture production and delayed the development of agriculture in Heilongjiang Province. Thus, the reasonable water and fertilizer measure is q uite important to the agricultural production in Heilongjiang province. A optimal water and fertilizer scheme is got by combining advanced irrigation methods and reasonable water and fertilizer applied ratio to improve water and fertilizer use efficiency and crop yield, and it has important theoretical and practical significance on maize planting in the semi arid region of Heilongjiang province.In this experiment, maize was select as study object, coupling effects of water and fertilizer were studied under sprinkling irrigation. Data including plant height, stem diameter, leaf area, soil water content and yield of maize and rainfall were analyzed by variance analysis, comparative analysis and statistical analysis, effects of water and fertilizer on height, stem diameter and leaf area were analyzed preliminary; The evapotranspiration and water requirement of maize were analyzed and water-fertilizer ratio under optimal WUE were obtained; The relationship between yield and N, P & water was analyzed and water-fertilizer ratio under maximum maize yield were obtained. The results are as follows based on the analysis:N plays a leading role in the growth of maize plant height. Both P and water have a certain promotion effect on the growth of maize plant height; P plays a leading role in the growth of maize stem diameter; Maize leaf area are affected by water and fertilizer directly, too much or too little water and fertilizer inhibit the growth of leaf area.Order of water requirement in each growth stage is: tasseling stage> jointing stage> seedling stage> filling stage> maturity stage. Water requirement at different stages increase when applying more N amount no matter P is in a lower level or a higher level. A lower P level and a higher P level have no significant impact on water requirement when N is fixed in a certain level.Maize daily water requirement increases first and then decrease. Daily water requirement reaches the maximum in jointing stage, 4.1-5.2 mm/d. Daily water requirement reaches the minimum in jointing stage, 1.3-1.4mm/d. average daily water requirement in the whole stage is 2.89 mm/d. Order of daily water requirement is: jointing stage> tasseling stage> filling stage> seedling stage> maturity stage.Effect on maize WUE is analyzed by modeling, the order is: water(x3)> N(x2)> P(x1),interactions between P&water shows as antagonism, while, interaction between N&P and N&water show as synergistic effects.Effect on maize yield is analyzed, the order is: N(x2)>P(x1)>water(x3);interactions between N&P and N&water show as synergistic effects, while, interaction between P&water shows as antagonism. The effect order is: P×N> N×water>P×water.The optimal water and fertilizer combination in this experiment from the perspective of best yield is P 60 kg/hm~2, N 148.4 kg/hm~2 and water 600 m3/hm~2, maize yield reaches as high as 15789 kg/hm~2 by the combination above, and corresponding WUE is 3.78 kg/m3. The optimal water and fertilizer combination in this experiment from the perspective of best WUE is P 60 kg/hm~2, N 345 kg/hm~2 and water 200 m3/hm~2, maize WUE reaches as high as 4.05 kg/m3 by the combination above, and corresponding yield is 15498 kg/hm~2. The optimal water and fertilizer combination in this experiment from the perspective of best economic benefit is P 60 kg/hm~2, N 138 kg/hm~2 and water 600 m3/hm~2, maximum benefit is 11254 yuan/hm~2. Those 3 water and fertilizer combinations are quite reasonable. Applied amount of water and fertilizer should be selected within the interval above according to different precipitation years, basic fertility situation and yield target.