Research On Rice Mulching Control Irrigation Technology In Thin Soil Layer In Cold Land

Xing’an Meng is an important national production base of green agricultural products,and the development of the rice industry has significant advantages.Among the four league cities where rice planting is concentrated in the region,Xing’an Meng has the largest planting area and the highest yield,accounting for about 1/3 of the total planting area and total output.Rice consumes a lot of water,flooding and irrigation makes most of the water lost in the form of evaporative leakage,while most of the rice irrigation area downstream of the Charsen Reservoir of Xing’an League is distributed along the banks of the river,the irrigation area has a thin soil layer,only 15-60 cm,below is the pebble layer,due to the thin soil layer,the waste of water is more serious.Therefore,the combination of mulching cultivation and controlled irrigation instead of traditional flooded irrigation has a far-reaching impact on the realization of water saving and high rice yield.This study simulates the local rice field scene,the bottom layer is laid with pebbles layer,the upper layer is artificially filled,and the soil layer thickness is 20-30 cm,30-40 cm and 40-50 cm,respectively,rice water-saving test is carried out on three thickness soil layers,and three kinds of irrigation treatment are set up: conventional irrigation(maintaining 3～5cm water layer),coated controlled irrigation I.(covered with degradation film,the lower limit is 70% of saturated moisture content),and coated controlled irrigation II(covered with degradable film,the lower limit is 85% of saturated moisture content),The differences in rice growth and production under mulched and conventional irrigation were explored,and irrigation modes suitable for different soil layers were proposed.(1)Under different thickness soil layers,the rice plant height under the three irrigation treatments showed a trend of first increasing and then decreasing,the plant height increased greatly in the middle tillering and jointing pregnancy stage,the plant height of conventional irrigation was always in the leading position,and mulching and controlled irrigation would inhibit the elongation in rice stems.The number of rice tillers was consistent with the change of plant height,and the maximum value was reached in the late tillering stage,when the number of tillers in conventional irrigation was the largest,and the final number of tillering in the yellow ripening period was higher than that of conventional irrigation.The effective tillering rate of each soil layer from largest to smallest order was: 20-30 cm and 30-40 cm soil layer mulching controlled irrigation II.> mulching controlled irrigation I.> conventional irrigation,40-50 cm soil layer mulching controlled irrigation I.> mulching controlled irrigation II.> conventional irrigation;The coarse stem and aerial biomass of rice reached the maximum in the milk-ripening stage and the yellow-ripening stage,respectively,and the order from large to small was consistent with the effective tillering rate,and the stem sheath dry matter output rate was between 10%～18.59% and the conversion rate was between 6%～13%.The blade output rate is between 5.9%～9.2%,and the conversion rate is between1.6%～2%.The dry matter transport capacity of single-hole rice stem sheath was 3～4times higher than that of leaves,and the dry matter transport of mulching and controlled irrigation was better than that of conventional irrigation.(2)The warming effect of mulching controlled irrigation was obvious in the 5cm tillage layer(between 7%～9.14%),and gradually decreased with the increase of the tillage layer.The soil temperature change of 5～15cm in different soil layers is basically the same,and the soil temperature of mulching and controlled irrigation during the day is higher than that of conventional irrigation,and the lower the soil moisture control,the more obvious the temperature changes with the outside world.(3)The water-saving rate of each irrigation treatment in different soil layers is between 20%～30%.The yield of 20-30 cm soil layer coated controlled irrigation II was the largest(576.41kg/mu),an increase of 6.16%,and the yield of coated controlled irrigation I.was the lowest(525.52kg/mu),with a decrease of 3.22%.The yield of30-40 cm soil mulching and controlled irrigation was higher than that of conventional irrigation,and the yields of mulching controlled irrigation I.and mulching controlled irrigation II increased by 5.76% and 10.77%,respectively.The yield of 40-50 cm soil layer coated controlled irrigation I was the highest(612.66kg/mu),with an increase of9.16%,and the yield of mulching controlled irrigation II increased by 7.2%.