| It is important to develop new soil conditioner to improve soil fertility and drought-resistant ability and increase crop yield in agriculture in arid areas. In this study, a newwater-saving agent was made with weathered coal, straw, oil foot, and Polyacrylamide. Soilcolumn and potted corn test were conducted to investigate the effects of this new water-savingagent on lou soil for its nitrate nitrogen leaching, physical and chemical properties, and soilwater features and the effects on growth, yield, and water use efficiency of summer maize.The main conclusions are as drawn as follows.(1) Application of water-saving agent can reduce the leaching of nitrate nitrogen in thesoil and has the ability of nitrate keeping. With the increase of application amount, the abilityof nitrate keeping was strengthened. When water-saving agent was applied in5-10cm soil,soil ammonium nitrogen leaching was remarkably increased. And the quantity of soilammonium nitrogen leaching increased with the increase of agent application rate. So theamount of water-saving agent should not exceed2%, and applied in upper soil layer to reducethe ineffective lose of nitrogen.(2) Water-saving agent increased the nitrate nitrogen content in the0-50cm soil layer.And the position of nitrate accumulation shifted upward, which can reduce the risk of nitratenitrogen leaching. The treatment of2%water-saving agent has the highest accumulation ofnitrate in the soil.(3) The application of water-saving agent can decrease soil bulk density. The applicationamount of2%remarkably decreased soil bulk density by5.02%in contrast to that of thecontrol treatment. Water-saving agent can increase soil saturated hydraulic conductivity incomparison with the control treatment. With the increase of water-saving agent, soil saturatedhydraulic conductivity increased. The soil saturated hydraulic conductivity of the treatmentsof0.5%,2%, and4%application amounts increased by1.05,3.17, and1.05times,respectively, in comparison with the control treatment. Water-saving agent treatments canimprove soil water-holding capacity and water release ability. The treatment of applicationrate of4%water-saving agent had the best water holding capacity and water release ability, or 8.70%and10.43%higher than those of the control treatment.(4) During the whole growth season of summer maize, the difference of waterconsumption between the treatments with and without water-saving agent is not obvious.Water consumption of summer maize between the treatments of4%and0.5%applicationrates has a big difference. In the treatment of higher application of water-saving agent, thewater consumption of summer maize was less. Namely, water saving agent can play the roleto reduce water consumption of summer maize.(5) At the harvest stage of summer maize, the weights of leaf, stem, husk plus cobweight, and hundred grains of the treatments with most water-saving agent were all increasedin comparison with the treatment with no water-saving agent, but the difference was not veryremarkable. Under the conditions of sufficient irrigation and moderate water stress,water-saving agent can improve the water use efficiency of summer maize. On severe waterstress, higher application rate of water-saving agent can get greater water use efficiency ofsummer maize.(6) In summary, the2%application rate of water-saving agent could keep moreinorganic nitrogen, and. The treatment of4%application rate could maintain more water andincrease corn yield and water use efficiency. |
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