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This scientific research has determined the water demand of soybean in different hydrological years to overcome problems such as the lack of water for the growth and development of grain crops. Water shortage is caused by low precipitation in the western part of Heilongjiang Province and the high incidence of drought. Drip irrigation, sprinkler irrigation and other irrigation models and irrigation systems were established and the impact of climate change on the water demand law of soybean growth was analyzed in the semi-arid areas in the western part of Heilongjiang Province. According to the meteorological data of Heshan Farm of Heilongjiang Province's Jiusan Administration Bureau from 1951 to 2018, the main parameters of soybean crop growth and the field soil layer data, the Mann-Kendall development trend test method was used to analyze the change trend of climate factors during the soybean growth period, and the CROPWAT model was used to analyze the change trend of water demand, effective rainfall and irrigation water flow throughout the year and each growth period. On this basis, the coupling degree of effective rainfall and soybean growth demand in different hydrological years was compared, and the corresponding irrigation scheme was determined. The results showed that the monthly average temperature in the whole growth period of soybean increased significantly, while the monthly average wind speed decreased significantly, and the demand for soybean decreased with the rate of 9.15 mm/10 years. The water consumption in the wet year was 396.06 mm, the water consumption in the normal year was 390.65 mm, the water consumption in the dry year was 420.21 mm, and the water consumption in the dry year was 459.96 mm. In different hydrological years, the coupling degree of local effective rainfall and soybean water demand shows a trend of increasing first and then decreasing. Under sprinkler irrigation conditions, the irrigation quota was 68.4 mm in the normal year, 121.1 mm in the dry year and 175.9 mm in the extremely dry year. Under the condition of drip irrigation, the irrigation quota in the normal year was 66.3 mm, the irrigation quota in the dry year was 111.6 mm, and the irrigation quota in the extremely dry year was 151.5 mm. According to the irrigation quota under different irrigation conditions, the effective rainfall in other hydrological years in the region is difficult to meet the water demand for soybean growth, except for the wet and flat years. Therefore, in different hydrological years, proper irrigation should be carried out at the flowering and podding stages of soybean to ensure high and stable yield. [ABSTRACT FROM AUTHOR]

The soybean in China northeastern black soil has low yield, low use efficiency of water and fertilizer, which has overly high amount of nitrogen residual. Three different drip irrigation mode amount (300 mm, 350 mm, and 400 mm) and five different amount of nitrogen was designed in this paper to study the influence of water and nitrogen controlling to the water and fertilizer use efficiency and the amount of nitrogen residual under drip irrigation mode. According to our experiment results, the water consumption of soybean increased with the growth of drip irrigation mode amount, and in all treatment, soybean consumed the most amount of water at seed filling period. There is no significant difference in water consumption amount between each treatment during seedling period, but there were significant differences in the water consumption of soybean at branching period, flowering and pod period, and seed filling period. Nitrogen fertilizer alone does not have significant influence on soybean water, but the interaction between nitrogen fertilizer and soybean had significant difference in water consumption amount. The yield reached the biggest amount of 3250 kg/hm² when nitrogen drip amount was 400 mm, and nitrogen application rate was 81 kg/hm². The yield increased with the growth of irrigation amount, but the yield increase rate became slow. When the nitrogen application amount was at a low level, there was a positive interaction between water and nitrogen, which showed a synergistic acceleration effect. When the nitrogen application rate was at a high level, there was a negative interaction between water and nitrogen. When the drip irrigation mode amount was 350 mm and the nitrogen application rate was 81 kg/hm2, the WUE was the highest, which was 0.60 kg/m3. In a certain range of nitrogen application, increasing irrigation amount can promote WUE, while the amount was over a certain range, WUE decreased. After harvest, the amount of nitrate nitrogen residual in the 0-100 cm soil varied greatly among different nitrogen fertilizer treatments, and the nitrogen fertilizer application amount was greater, the nitrogen residual was greater. In the W3N3 treatment which has the highest yield, the yield was at 42 kg/hm2 less than the W3N4 treatment at the highest amount of nitrate nitrogen residual, which is a reduction of 35.78%. The results showed that proper combination of water and nitrogen application could reduce nitrogen residual in soil after harvest. The research results can provide theoretical basis and technical support for the efficient utilization of water and fertilizer resources in the black soil region located in northeastern China. [ABSTRACT FROM AUTHOR]

Laser shock imprinting (LSI) is used to fabricate a hydrophobic Cu surface with multiscale microtextures in this work. To obtain multiscale microtextures in a micromould, a first pass of laser marking was used to increase the roughness of the original surface. Then a second pass of laser marking was used to manufacture periodic groove microstructures on the micromould. Thereafter, LSI was used to replicate the multiscale microtextures of the micromould on the sample surface. The surface morphology, wettability and surface roughness of samples fabricated at different laser shock energies were investigated. The experimental results indicate that the sample can successfully replicate the microtextures of the micromould surface after LSI and the greater the laser shock energy, the higher the degree of replication of the sample to the microtextures of the micromould. As the laser shock energy increases from 620 to 1290 mJ, the profile and roughness of microtextures of sample surface gradually close to those of micromould. In addition, the static contact angles measurement results show that the sample surface wettability changes from hydrophilic to hydrophobic after LSI, and the contact angles increase with the increase of laser shock energy. Due to the anisotropic wettability, the static contact angles perpendicular to groove microstructures are apparently larger than that in the parallel direction. The maximum static contact angles of the sample in perpendicular and parallel directions are 124 and 109°, respectively, when the laser shock energy was 1290 mJ. This work provides a new approach for fabricating hydrophobic surfaces, which can realize the wider practical production value of LSI in the direction of preparing superhydrophobic surfaces. [ABSTRACT FROM AUTHOR]