Effects Of Seeding Rate And N Fertilizer On The Lodging And Yield Of Oats

The experiment was conducted on Huazang Deer Farm in Tianzhu in April-October, 2006. Split-plot design was used to investigate the effects of seeding rate and N fertilizer on biomass and grain yield oats in order to probe the mechanism of lodging and yield reduction of oat under different cultivation measures. The main results are as follows:(1) Seeding rate and N fertilizer had significant effects on lodging resistance in oats. With the increasing of seeding rate, single stem fresh weight and CLI increased significantly, while mechanic intensity reduced. The four factors increased with the increasing N fertilizer. Base internode haleness closely related to lodging resistance with the 2nd > the 1st > the 3rd internode. It affected CLI as the 1st > the 2nd> the 3rd. Height of gravity center had the highest co-relation with CLI (r=0.6893**); plant height and stem mechanic intensity negatively related to CLI (r=-0.0023;r=-0.5280). Stem mechanic intensity had the biggest effect on CLI (P=0.8329), followed by single plant fresh weight (P=0.7493).(2) Length of 2nd internode had a significant negative relation with CLI. When the sum of the 1st and 2nd internode accounted 22% of the stem height, good lodging resistance and high yield could achieve.(3) Lodging resistance decreased with increasing seeding rate. Ronald was the most lodging resistant and Baiyan No. 5 was the poorest. With the increasing of N fertilizer, mechanic intensity increased and both Ronald and Denmark 444 showed the highest lodging resistance under treatment of 60 kg/hm2 + 40kg/hm2 N, while two naked oat varieties gave the best performance under 100kg/hm2 N treatment.(4) Stem height, base internode length increased as seeding rate increased with the 2nd > 1st internode. Both factors reached the highest under 100kg/hm2 N treatment. The same volume of N applied separately did not affect the two factors significantly.(5) All the varietiesincreased their LAI, stem and leaf dry weight with increasing seeding rate and gave the highest performance in LAI under 100kg/hm2 N treatment. For stem and leaf dry weight, the best N treatment was 60kg/hm2+40 kg/hm2.(6) N content also influenced lodging resistance. Ronald and two naked oats increased their N residue in stems as seeding rate increased. The highest content was found in Denmark 444 under 112.5 kg/hm2 N treatment.(7) Fresh and dry biomass, fresh to dry ratio showed increasing trend as seeding rate increased. Denmark 444 had the highest fresh and hay yield, while Ronald was the lowest. With the increasing of N fertilizer, Baiyan No. 2 and Denmark 444 improved their fresh and hay yield, while Baiyan No. 5 and Ronald did not show significant change.(8) Tiller number, grains per panicle, thousand-grain weight and economic coefficient reduced with increasing seeding rate, while biomass increased accordingly. All the varieties achieved the highest effective tiller and grain yield under 112.5 kg/hm2 N treatment.(9) Grains per panicle, thousand-grain weight and effective tiller significantly co-related to grain yield. Total tiller number negatively related to grain yield. The effective way to increase grain yield was to increase grains per panicle, thousand-grain weight and effective tiller, and control total tiller number at the same time. The four factors contributed to grain yield as thousand-grain weight > effective tiller > grains per panicle.(10) The effect of seeding rate on N fertilizer use efficiency showed an increment followed by a decline; N fertilizer use efficiency reduced with the increasing N fertilizer.