| The Tibetan Plateau is an important production base of livestock production in China.Oat is characterized by drought resistance,cold tolerance,high grass yield and nutrient,which is a indispensable forage in livestock production of alpine meadow region.Sowing date and sowing rate are important management methods in crop production,they have great practical significance to ensure the growth process and productivity of the forage in the alpine region.In this study,a field experiment was carried out in Hongyuan County,Aba Prefecture,Sichuan Province in the eastern margin of the Tibetan Plateau in 2018.Three oat varieties with different maturities:Qingyin No.2(early maturity),Qinghai 444(early maturity)and sweet oats(mid-late maturity:)were selected to explore their growth and production characteristics under three sowing date and five sowing rate.The purpose of the study is to provide a scientific basis for pasture cultivation of oat grass in the Tibetan alpine region.The main results that obtained by this study were as follow:1.The flowering stage of the mid sowing treatment(June 4)was the shortest of the three oat varieties,with Qingyin No.2,Qinghai 444 and sweet oats were 70,72and 83 d.At the end of the growing season,Qingyin No.2 and Qinghai 444 reached wax maturity stage when they were planted on May 20,and can only be reached milk stage and grain filling stage when the sowing date was delayed by June 4 and June 18,respectively.The sweet oat only reached milk stage,grain filling stage and flowering stage,grain under the three sowing dates.The height of all oats were significantly reduced with the delay of sowing date.The highest dry matter yield of three oat varieties at flowering stage was appeared on May 20,June 4 and June 18,respectively,which were 8.3 t/hm~2,11.6 t/hm~2,and 12.8 t/hm~2;Therefore,for the objective of harvesting forage,Qingyin No.2 was suitable for sowing in mid-to-late May,and Qinghai 444 and sweet oats was suitable for sowing in early June and mid June,respectively.2.Sowing rate has little effect on the phenology of different varieties of oats.Qingyin No.2 and Qinghai 444 reached the maximum dry matter yield at flowering stage under sowing rate of 150 kg/hm~2,was 15.0 t/hm~2 and 13.4 t/hm~2,respectively.While the maximum dry matter yield of sweet oat appeared in 60 kg/hm~2,was 18.5t/hm~2.At the end of the growing season,Qingyin No.2 and sweet oat reached the maximum yield under sowing rate at 30 kg/hm~2,was 19.8 t/hm~2 and 24.7 t/hm~2,respectively.While the maximum yield of Qinghai 444 appeared in 100 kg/hm~2(20.0t/hm~2).With the increase of sowing rate,the height of three varieties increased first and then decreased and peaked at 150 kg/hm~2,was 153.6,133.6 and 134.2 cm,respectively.Sowing rate had no significant effect on the leaf number of main culm,with Qingyin No.2 and Qinghai 444 were 6-7,and that of sweet oats was 8-9.At heading and flowering stages,leaf area index(LAI)of the three cultivars increased with the increase of sowing rate.The effective tillers and basal diameter of the three tested varieties decreased with the increase of sowing rate during the whole growth period.The suitable sowing rate of Qingyin No.2 and Qinghai 444 was 150 kg/hm~2,while that of sweet oats was 60 kg/hm~2.3.In Hongyuan County,Qingyin No.2 and Qinghai 444 should be planted at 150kg/hm~2 in mid-May and early June,respectively,while they can reache flowering stage on August 15 and August 27,respectively.The sweet oat should be planted at150 kg/hm~2 in mid June,then will reached flowering stage on September 28 and mowing at this time. |
PDF Full Text Request