| In order to explore the suitable planting density and appropriate mowing period of oat forage grass production in the western Songnen Plain,with the region’s main oat varieties of naked oat Baiyan 2,husked oat Baiyan 7 as the experimental material,and six planting density treatments were set by random block group experimental design: 300×104plant /hm2,450×104plant /hm2,600×104plant /hm2,750×104plant /hm2,900×104plant /hm2,and 1050×104plant /hm2 were used to analyze the effects of planting density on population and individual traits,photosynthetic characteristics,seed yield and quality,and forage yield and quality at different mowing periods of two oat varieties.The main test results are as follows:1.With the increase of density,the number of total stem of oat population increased,the tiller rate increased,but the tiller number decreased.The density increase significantly increased the leaf area index of oat before anthesis,but the lower leaf area index of higher density decreased faster after anthesis,which was not conducive to the maintenance of photosynthetic production area of post-anthesis population.The plant height,stem diameter,panicle length,spikelet number,grain number per panicle and dry matter mass per plant decreased significantly with the increase of density.2.The SPAD value,net photosynthetic rate(Pn),stomatal conductance(Gs),intercellular CO2 concentration(Ci)and transpiration rate(Tr)of oat flag leaves decreased significantly with the increase of density,and the photosynthetic performance of flag leaves at low density was better.3.With the increase of density,the number of spikelets of the two varieties increased significantly,the number of grains per spike and 1000-grain weight decreased significantly,and the grain yield increased first and then decreased.The maximum yield of Baiyan 2 at 450×104plant /hm2 was 2406.73kg/hm2,while the maximum yield of Baiyan 7 at 600×104plant /hm2was3570.77 kg/hm2.4.The forage yield of oat at different mowing period showed different trends with the increase of the density.The maximum yield of fresh grass mowed on the 21 d after anthesis of750×104plant /hm2 treatment of Baiyan 2 was 31763.33 kg/hm2,and the highest hay yield was11515.00 kg/hm2 on the 28 d after anthesis of 750×104plant /hm2 treatment.On the 21 d afteranthesis of 900×104plant /hm2 treatment,the fresh grass yield of Baiyan7 reached the highest of38444.00 kg/hm2,and the highest hay yield was 13792.00 kg/hm2 on the 28 th day after anthesis of 900×104plant /hm2 treatment.5.The grain nutrient content and nutrient yield of oat seeds were significantly different at different densities.The crude protein content in seeds of Baiyan 2 increased first and then decreased with the increase of the density,the content of crude fat and starch decreased with the increase of the density,and the content of soluble sugar and β-glucan increased with the increase of the density.The content of crude protein and crude fat in the seeds of Baiyan 7 decreased with the increase of the density,the content of starch and soluble sugar first increased and then decreased with the increase of the density,and the content of β-glucan increased with the increase of the density.The seed nutrient yield of the two varieties increased first and then decreased with the increase of the density.Baiyan 2 and Baiyan7 were more conducive to high quality grain production in 450×104plant /hm2 and 600×104plant /hm2,respectively.6.The nutritional content of oat forage varied significantly between different densities,and the nutritional content of oat forage varied significantly during different mowing periods.The content of crude protein,acid and neutral washing fiber in forage grass of Baiyan 2 increased first and then decreased with the increase of the density,while the content of crude fat decreased with the increase of the density.The content of crude protein and crude fat of Baiyan 7 decreased with the increase of the density,while the content of acid and neutral washing fiber increased with the increase of the density.The content of crude protein and crude fat in forage grass of Baiyan 2 decreased first and then increased with the retarder of mowing period,while the content of acid and neutral washing fiber increased first and then decreased with the retarder of mowing period.The crude protein content of forage grass of Baiyan 7 decreased first and then increased,the crude fat content increased first and then decreased,and the content of acid and neutral washing fiber increased first and then decreased with the retarder of mowing period.7.The digestible dry matter(DDM),dry matter feed intake(DMI)and relative forage value(RFV)of oat forage decreased with the increase of density and the retraction of mowing period.Both varieties had the highest feeding value at 300×104plant /hm2 booting stage.8.The principal component analysis was used to comprehensively evaluate the yield and nutritional quality of oat,and it was found that the best performance of Baiyan 2 treated with 750×104plant /hm2 on the 21 d after anthesis mowing was the best,and that of Baiyan 7 treated with900×104plant /hm2 on the 21 d after anthesis mowing was the best.Considering the effects of planting density on individual traits,photosynthetic characteristics,grain yield and quality,and forage yield and quality at different cutting periods,it was found that the appropriate planting density of high quality and high yield varied with different varieties and production purposes.For the purpose of seed production,the suitable planting density of Baiyan 2 and Baiyan 7 was 450×104plant /hm2 and 600×104plant /hm2,respectively.For the purpose of forage grass production,the suitable planting density of Baiyan2 and Baiyan 7 was 750×104plant /hm2 and 900×104plant /hm2,respectively,and it was most suitable for mowing at about the 21 d after anthesis. |
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