| Water, fertilizer,gases,heat and light are the necessary condition for plant growth, and gases is not only the raw materials for crop photosynthesis but also the fundamental elements ensures the crop normal breathing.The gas in the soil is the necessity to decompose the soil microorganisms and the nutrient.So the study of the effects of gases on plant growth has important meaning in improving the the environment of crop growth, enhancing the root activity, improving the utilization of water and fertilizer and promoting the crop growth of the ground and underground parts.As to study the effects of the gases in soil on crop growth, search for rhizosphere aeration and irrigatation on crop growth and the soil environmental, setting three irrigatation levels (95%, 85% and 75% of the water of the field,using H,M,L to express),using the potted corn methods, as the time interval for ventilation once in every day,three says and five days(using T1,T3,T5 to express), to study the effects of rhizosphere aeration and irrigatation on physical index ,shape indicators of corn and the soil enzyme activity.The results indicate that:the root growth of rhizosphere aeration is well-developed than no aeration in the same irrigatation level,but the length of root is smaller than no aeration, the fresh weight ,dry weight, the length and weight of ears of rhizosphere aeration are all Larger than no aeration,but RSR is smaller than no aeration. Rhizosphere aeration promoted the growth of plant height,leaf area,stew width and the chlorophy content of corn. the per day net growth of plant height,stew width and the chlorophyll content during the days of 0-20 d are larger than other stages,and the plant height and the chlorophyll content of HT3 are the largest,as the 2.97 cm, 2.30 mg/g per day,LT0 is the smallest,as the 2.67 cm,2.01 mg/g, the percentage of increasing is 11.24%,14.43% respectively. The per day net growth of leaf area during 40-60 d is larger than other stages,and HT1 is the largest,as 111.0 cm2,LT0 smallest,73.3 cm2, the percentage of increasing is 51.44%.The root activity of corn increased significantly in the conditions of rhizosphere aeration,20 days after the seedlings,the root activity of rhizosphere aeration is all more than 30μg·g-1·FW·h-1,but no rhizosphere aeration is all within 22.910～25.104μg·g-1·FW·h-1.The root activity of HT1 is the largest(39.301μg·g-1·FW·h-1),and LT0 is the smallest(22.910μg·g-1·FW·h-1), the percentage of increasing is 71.54%. The root activity of rhizosphere aeration is all more than 20μg·g-1·FW·h-1 60 days after the seedlings,but no rhizosphere aeration is all within 14.563～17.609μg·g-1·FW·h-1,TH1 is the largest(29.796μg·g-1·FW·h-1),MT1 is the second largest(29.613μg·g-1·FW·h-1),and LT0 is the smallest(14.563μg·g-1·FW·h-1), the percentage of increasing are 104.60% and 103.34% respectively.The root activity of all treatment is less than 10.0μg·g-1·FW·h-1 100 days after the seedlings, and the rate of reduction is larger compared with 60 days after the seedlings, and the biggest reduction of all are HT1 and MT1, as 67.90% and 71.19% respectively.Rhizosphere aeration has a significant influence on the enzyme activity in soil, the difference of dehydrogenases activity and perhydrolase activity are bigger in conditions of rhizosphere aeration and no aeration 60 days after the seedlings, dehydrogenases activity of HT1 is largest(40.195 FPE mg·g-1·d-1 ) ,MT1 is the second largest(39.585 FPE mg·g-1·d-1),LT0 is the smallest(30.979 FPE mg·g-1·d-1), the percentage of increasing are 29.75% and 27.78% respectively,perhydrolase activity of MT1 is the largest(0.86 ml.g-1.30min-1),and HT3 is the second largest largest (0.85 ml.g-1.30min-1),LT0 is the smallest(0.61 ml.g-1.30min-1), the percentage of increasing are 40.98% and 39.34% respectively. Rhizosphere aeration has a significant influence on urease activity 80 days after the seedings,and the largest of HT1 (5.587 mg·g-1·d-1NH3-N),the second largest (5.095 mg·g-1·d-1NH3-N) has increased 43.59% and 30.93% compared with the smallest LT0(3.891 mg·g-1·d-1NH3-N). Physical index of corn and the enzyme activity are contained under low irrigation,but rhizosphere aeration has relieved this situation.And rhizosphere aeration has smaller influence on transpiration,but promoted nutrients sorption in soil.The experiment results showed that rhizosphere aeration and irrigation could improve the microenvironment of soil, enhance the root activity, promote the enzyme activity in soil and the utilization of water and fertilizer, improve the growth of crop, In the conditions of high irrigation and high ventilation, it can get more corn stems growth rate or with low irrigation and ventilation can ensure the growth of maize, getting the target of saving water and high water use efficiency.and provide the theoretical basis to further exploring the effects of rhizosphere aeration on the growth of crop. |
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