Effects Of Elevated CO₂, Soil Moisture And Nitrogen On The Growth And Nutrient Uptake And Utilization Of Winter Wheat

Effects of elevated CO₂ concentration on crop have been paid more and more attention, and water and nitrogen are the necessary conditions of crop growth. Winter wheat is one of the main food crops in China. The study aims to elucidate the interactive effects of elevated CO₂ concentration, soil moisture and nitrogen on the growth and nutrient uptake and utilization of winter wheat, which could provide guidance for appropriate practical fertilizer and water managements under future climate change. Pot experiment in wheat variety' Zhong Mai 175' with the free air CO₂ enrichment ?FACE? system were used in the research. The research studied the growth and nutrient uptake and utilization of winter wheat under different CO₂ concentration (the ambient CO₂ concentration 391 ±40 ?mol ·mol^-1 and the elevated CO₂ concentration 550±60 ?mol ·mol^-1), soil moisture ?wet and drought conditions as 75% and 55% field maximum water capacity? and Nitrogen fertilizer ?adequate nitrogen fertilizer and without nitrogen fertilizer?. The conclusions as followed.1 Effects of elevated CO₂ concentration, soil moisture and nitrogen on the growth of winter wheat.Compared with the normal CO₂ concentration, elevated CO₂ concentration can promote early flowering by 1 day, the growth period of winter wheat was shorted 1 day, e growth period was shorted by 1?5 days under the drought or no nitrogen fertilizer conditions.Elevated CO₂ concentration increased plant height and leaf area, increased 7.3% dry matter accumulation, and it inhibited the effects of CO₂.concentration without adequate water and fertilizer conditions. Elevated CO₂ concentration increased dry matter of winter wheat s leaf sheath and stem increased redistribution to Spike, and it increased effective spikelets byl.2%?5.0%, reduced infertility spikelets by 16.1%?75%, the grain yield was increased 8.0%?17.0%.2 Effects of elevated CO₂ concentration, soil moisture and nitrogen on shoots, roots and whole plant N, P, K concentrations of winter wheatElevated CO₂ concentration decreased shoots and whole plant N concentrations by 21.2% and 20.1%, the effects of elevated CO₂ concentration on the roots N concentration was related to soil moisture and nitrogen, roots N concentration increased 39.2% under sufficient nitrogen conditions, when nitrogen deficiency, roots N concentration increased 15.4% under drought conditions, roots N concentration decreased 4.9% under moist conditions. Elevated CO₂ concentration decreased shoots and whole plant P concentrations by 11.7% and 12.9%under sufficient soil moisture and nitrogen conditions, but it increased shoots and whole plant P concentrations by 5.7%-37.7%and 4.6%-36.1% under drought or no nitrogen conditions, roots P concentration decreased17.0%. Elevated CO₂ concentration decreased shoots and whole plant K concentrations 9.7%and 8.0% under sufficient soil moisture conditions, but it increased 9.3% shoots and 10.4% whole plant K concentrations under drought conditions, roots K concentration increased 37.3%.3 Effects of elevated CO₂ concentration, soil moisture and nitrogen on shoots, roots and whole plant N, P, K uptake of winter wheat and soil available N, P and KElevated CO₂ concentration on the shoots and whole plant N accumulation were related to soil moisture and nitrogen, N accumulation increased by 3.2% and 3.1% under sufficient soil moisture and nitrogen conditions, the shoots N accumulation decreased between 12.1% and 29.4% under other conditions, the whole plant N accumulation decreased between 12.5% and 28.5% under other conditions, roots N accumulation increased2.7%. Elevated CO₂ concentration increased shoots and whole plant P accumulation by 21.0% and 18.4%, roots P accumulation decreased 22.2%. Elevated CO₂ concentration increased shoots, roots and whole plant K accumulation by 6.8%,14.0% and 7.3%.Elevated CO₂ concentration on the soil available N content were related to soil moisture and nitrogen conditions, available N content increased 5.1% under adequate nitrogen conditions, available N content decreased 6.2% under moist and no nitrogen conditions, available N content increased 5.7% under drought and no nitrogen conditions. Elevated CO₂ concentration on the soil available P content were related to nitrogen conditions, available P content increased 21.1% under adequate nitrogen conditions, available P content decreased 20.0% under no nitrogen conditions. Elevated CO₂ concentration only increased 14.6% the soil available N content under drought and no nitrogen conditions, the soil available N content decreased under other conditions.4 Effects of effect of elevated CO₂ concentration, soil moisture and nitrogen on nutrient use efficiency of winter wheatElevated CO₂ concentration increased 21.8% apparent N utilization and N agronomic efficiency, water deficit inhibited this effect, elevated CO₂ concentration can't compensate for the side effects of water deficit. Elevated CO₂ concentration increased 29.3% N fertilizer use efficiency of winter wheat, and its effect was more obvious under no nitrogen conditions. Elevated CO₂ concentration increased 14.1% P fertilizer use efficiency of winter wheat, the conditions without water or nitrogen inhibited this effect. Effects of effect of elevated CO₂ concentration on K fertilizer use efficiency was due to soil moisture, K fertilizer use efficiency increased 9.1% under moist conditions, K fertilizer use efficiency decreased under drought conditions. Effects of effect of elevated CO₂ concentration on N physiological efficiency varies due to soil moisture, N physiological efficiency decreased 18.6% under moist conditions, N physiological efficiency increased 46.6% under drought conditions. Elevated CO₂ concentration increased 42.3% P and 94.8% K physiological efficiency of winter wheat.5 Effects of elevated CO₂ concentration, soil moisture and nitrogen on shoots, roots and whole plant C content concentration and C uptake of winter wheatElevated CO₂ concentration decreased 2.6% shoots and 2.2% whole plant C concentration, roots C concentration was due to soil moisture and nitrogen conditions, roots C concentration increased 6.6% under moist conditions, the roots C concentration decreased 9.2% under drought and nitrogen conditions, roots C concentration increased 23.8% under drought and no nitrogen conditions. Elevated CO₂ concentration shoots and whole plant C uptake of winter wheat increased5.3% and 5.1%, roots C uptake of winter wheat was due to soil moisture, roots C uptake increased 12.9% under moist conditions, roots C uptake decreased 13.3% under drought conditions.6 Effects of elevated CO₂ concentration, soil moisture and nitrogen on shoots, roots and whole plant C/N, C/P, C/K,N/P,N/K ratio of winter wheatElevated CO₂ concentration increased 27.7%shoots and 26.6% whole plant C/N ratio of winter wheat, the roots C/N ratio was related to nitrogen conditions, roots C/N ratio decreased 8.8% under adequate nitrogen conditions, roots C/N ratio increased 12.4% under no nitrogen conditions. Elevated CO₂ concentration increased 9.5%shoots and 28.1% whole plant C/P ratio of winter wheat under adequate soil moisture and nitrogen conditions, the shoots C/P ratio decreased between 9.3% and 30.3%, and whole plant C/P ratio decreased between5.7% and28.2% under drought or no nitrogen conditions, roots C/P ratio increased 28.2%. Elevated CO₂ concentration increased 8.8%shoots and 7.4%whole plant C/K ratio of winter wheat under moist conditions, shoots and whole plant C/K ratio decreased by12.1% and 12% under drought conditions, roots C/K ratio increased 4.6% only when soil moisture and nitrogen was lack, roots C/K ratio decreased.between 0.4% and 26.7% under other conditions.Elevated CO₂ concentration increased shoots and whole plant N/P, N/K ratio of winter wheat under adequate soil moisture and nitrogen conditions, the N/P ratio of winter wheat increased7.9% and 10.0%, the N/K ratio of winter wheat increased 13.0% and 11.0%, the shoots and whole plant N/P, N/K ratio decreased under drought or no nitrogen conditions,the shoots N/P ratio decreased between 35.8% and 44.0%,the whole plant N/P ratio decreased between 34.7% and 41.9%,the shoots N/K ratio decreased between 27.0% and 35.1%,the whole plant N/K ratio decreased between27.0%and33.5%,the roots N/P ratio increased 28.7%, the roots N/K ratio decreased11.3%.