The Effects Of The Water And Nitrogen Coupling On The Bromus Inermis Yield Formation And Physiological Characteristics

This experiment are mainly talking about Bromus inermis. We want to find the effect of the water and nitrogen coupling on the Bromus inermis Growth, photosynthesis and Nitrogen Metabolism in the farm of Inner Mongolia University For the Nationlities. In the experiment, the moisture content of the ground was divided into three grade, 40 percent, 60 percent and 80 percent(marked byW1, W2, W3) and nitrogenous fertilizer of the ground was also divided into five grades, 0kg/hm2、75kg/hm2、150kg/hm2、225kg/hm2、300 kg/hm2(marked by N0、N1、N2、N3、N4).Therefore, there were 15 combinations. The followings are our research results:1.Different water and nitrogen combinations have obvious coupling effects on growth of the Bromus inermis. According to the increase of the percentage of moisture content and nitrogenous fertilizer, the average height of the Bromus inermis increase and treatments of moisture and nitrogenous fertilizer are significantly different. One year later, the group W3N4 has the highest Bromus inermis; in addition, this group has obvious advantage than other groups. The Bromus inermis of W3N1 is 111.0%、104.8% and 75.3% higher than the lowest W1N4 on seeding stage, early tillering and late tillering. Two years later, W3N4 is the highest Bromus inermis, for the more, it’s 61.2 % longer than the lowest W1N0.2. The water and nitrogen coupling has obvious coupling effects on the Bromus inermis branch number. The data increased with the increasing moisture and nitrogenous fertilizer. Treatments of moisture and nitrogenous fertilizer were significantly different. W3N3’s tiller was the largest. In addition, one year and two years later, the average of branch number can reach 148.6 and 173.67, which was signficantly higher than other combinations and even 108.4% and 107.6% higher than the smallest W1N1.3.The water and nitrogen coupling has obvious effects on yield formation of the Bromus inermis. Its biomass in every stage was increased as the increasing moisture and nitrogenous fertilizer and treatments of moisture and nitrogenous fertilizer were significantly different. The biomass of plant of W3N3 was the highest on every stage. And one year and two years later, biomass of plant can reach 13.92 and 13.40, which was obviously higher than other combinations and even 189.9% and 107.6% higher than the lowest W1N1.4. Water and nitrogen combination had obvious coupling effects on physiological characteristics of the Bromus inermis. Soluble protein content, free amino acid content and nitrate reductase’s activity increased with the increasing nitrogenous fertilizer, while they reduced with the increasing moisture. The group W3N4 has the highest soluble protein content. The Bromus inermis soluble protein content of W3N4 is 37.0%,71.3% and 70.0% higher than the lowest W1N0 on seeding stage, early tillering and late tillering. The group W1N4 has the highest free amino acid content. The Bromus inermis free amino acid content of W1N4 is 75.3%, 64.7% and 59.8 % higher than the lowest W3N0 on seeding stage, early tillering and late tillering. In addition, the group W1N4 has the highest nitrate reductase’s activity. The Bromus inermis nitrate reductase’s activity of W1N4 is 217.0%,353.9% and 175.4% higher than the lowest W3N0 on seeding stage, early tillering and late tillering.5.Water and nitrogen combination had obvious coupling effects on Photosynthetic rate of the Bromus inermis. With the increasing conetent of soil water and nitrogen, chlorophyll content in period increased first and then decreased, but the photosynthetic rate(Pn) and transpiration rate(Tr) increased gradually. The maximum value of Photosynthetic rate on seeding stage and early tillering appeared on 11:00, while the minimum appeared on 17:00. The maximum value of Transpiration rate appeared on 15:00. One more thing, the Bromus inermis’ Pn and Tr of N4 obviously went down.6. Water and nitrogen combinations have obvious coupling effects on nitrogen utilization ratio of the Bromus inermis. The nitrogen utilization ratio increased with the increasing percentage of moisture content and nitrogenous fertilizer. The groups N3 has the highest nitrogen utilization ratio in different moisture content treatments. To add the nitrogen for a further step, the nitrogen utilization ratio would go down obviously.7.According to the above research, water and nitrogen combinations have obvious coupling effects on the Bromus inermis including yield, yield formation, Photosynthetic physiological characteristics and nitrogen physiological characteristics.Under our experiments’ condition, the best water and nitrogen combination is group W3N3. In other words, when the moisture content of the ground was 80 percentage and nitrogenous fertilizer of the ground was 225kg/hm2, the Bromus inermis can gain the best yield.