种植密度对陇东地区饲用燕麦生产性能及光合特性的影响

Effects of planting density on production performance and photosynthetic characteristics of forage oats in Longdong Region

摘要:

【目的】 探明不同种植密度对饲用燕麦农艺性状、草产量及光合特性的影响，以及陇东地区饲用燕麦的最适种植密度。【方法】 以燕麦中熟品种梦龙和晚熟品种爱沃为试验材料，在陇东黄土高原旱作区进行了300万株/hm²（D1）、375万株/hm²（D2）、450万株/hm²（D3）、525万株/hm²（D4）、600万株/hm²（D5）、675万株/hm²（D6）6个种植密度的田间比对试验。【结果】 随种植密度增加，2个饲用燕麦品种的生长天数缩短，株高、茎粗、单株分蘖数呈下降趋势；2个饲用燕麦品种开花期叶面积指数随密度增加先升高后降低，叶绿素含量随密度增加而下降，中熟品种梦龙的各项光合参数均在D1下最高，晚熟品种爱沃的净光合速率、蒸腾速率和气孔导度在D2下最高，胞间CO2 浓度在D1下最高；2个饲用燕麦品种的鲜、干草产量均随密度增加先升高后降低，中熟品种梦龙的鲜、干草产量在D4下最高，分别为 22 878. 1 和 9 867.78 kg/hm²，晚熟品种爱沃的鲜、干草产量在D3下最高，分别为20 852.09和8 129 kg/hm²。【结论】 在陇东地区春播的情况下，选择中熟品种梦龙为宜，其获得饲草高产的种植密度为525 万株/hm²，晚熟品种爱沃获得饲草高产的种植密度为450万株/hm²。

Abstract:

【Objective】 This study investigates the influence of different planting density on agronomic traits， grass yield and photosynthetic characteristics of forage oats，and the optimum planting density of forage oats in the Longdong region.【Method】 In this experiment，the medium-maturing variety Magnum and the late-maturing variety Everleaf 126 were used as the test materials. Six planting densities of 3 million plants/hm2（D1），3. 75 million plants/hm²（D2），4. 5 million plants/hm²（D3），5. 25 million plants/hm²（D4），6 million plants/hm²（D5），6. 75 million plants/hm² （D6） were tested in the dryland area of the Loess Plateau in Longdong.【Result】 As planting identity increased，the growth duration of both forage oat varieties decreased，and the plant height，stem diameter，and the number of tillers per plant all showed a decreasing trend. The leaf area index at anthesis increased and then decreased with higherdensities in two forage oat varieties. Chlorophyll content decreased with increasing density. All photosynthetic parameters of Magnum（medium-maturing variety）were highest at D1. Net photosynthetic rate，transpiration rate and stomatal conductance of the late-maturing variety Everleaf 126 were highest at D2，while theinter-cellular CO2 concentration was highest at D1. Both fresh and hay yields of the two forage oat varieties increased and then decreased with higher planting densities. The fresh yield and hay yield of Magnum were highest at D4，with 22 878. 1 kg/hm² and 9 867. 78 kg/hm²，respectively. For Everleaf 126， the highest yields occurred at D3，with 20 852. 09 kg/ hm² for fresh yield nd 8 129 kg/hm² for hay yield.【Conclusion】 In the case of spring sowing in the Longdong region， it is appropriate to choose the medium-maturing variety Magnum，which has a high yield of forage planting density of 5. 25 million plants/hm²，and the late-maturing variety Everleaf 126 to obtain a high yield of forage planting density of 4. 5 million plants/hm².