| Agropyron mongolicum and Bromus inermis are important high-quality grasses for grassland animal husbandry and grassland ecological construction.Density is one of the main factors affecting forage and seed yield in artificial grassland.In this paper,a two-factor split-plot experimental design of row spacing and sowing rate was adopted.Four row spacing(H1:20,H2:30,H3:40,H4:50 cm)gradients were set as the main factors,and four sowing rates(D1:10,D2:15,D3:20,D4:25 kg·hm-2)gradients were set as the secondary factors.The effects of row spacing and sowing rate on the production performance and soil enzyme activity of Agropyron mongolicum and were studied.The main research results are as follows:1.Row spacing and sowing rate had significant effects on plant height,stem diameter,total tiller number,leaf stem ratio,leaf area,hay yield,fresh grass yield,crude protein,crude fat,crude ash,neutral detergent fiber and acid detergent fiber of Agropyron mongolicum,and there was a significant interaction between row spacing and sowing rate.Under H1D1 treatment,the hay yield and fresh grass yield of Agropyron mongolicum were the highest,which were 10877.69 kg·hm-2 and 23873.75 kg·hm-2 respectively.Row spacing and sowing rate had significant effects on plant height,stem diameter,total tiller number,dry-fresh ratio,leaf area,hay yield,fresh yield,crude fat,crude ash and neutral detergent fiber of Bromus inermis,and there was significant interaction.The hay yield and fresh yield of Bromus inermis were the highest under H1D3 treatment,which were 8606.64 kg·hm-2 and 21674.83 kg·hm-2 respectively,respectively.Based on the comprehensive evaluation of principal components,the optimal row spacing and sowing rate for the production of Agropyron mongolicum were 20 cm and 10 kg·hm-2 respectively.The optimal row spacing and sowing rate for the production of Bromus inermis were 20 cm and 20 kg·hm-2 respectively.2.Row spacing had a very significant effect on the effective tiller number,spikelet number,floret number,seed number,1000-grain weight,spike length,spike weight,actual seed yield and performance seed yield.Sowing rate had a very significant effect on spikelet number,floret number,seed setting rate,spike length and spike weight.Row spacing and sowing rate had a significant interaction on spikelet number,floret number,1000-grain weight,spike length,spike weight,actual seed yield and performance seed yield.The actual seed yield and performance seed yield of Agropyron mongolicum were the highest under H1D2 treatment,which were 2389.37 kg hm-2 and 4650.67 kg·hm-2 respectively.The path analysis showed that floret number,seed number,panicle length and effective tiller number had direct effects on the seed yield of Agropyron mongolicum,and spikelet number had indirect effects.The comprehensive analysis of grey correlation degree showed that the optimal row spacing was 20 cm and the sowing rate was 15 kg-hm-2.Row spacing and sowing rate had significant effects on spikelet number,floret number,seed number,1000-grain weight,panicle length,actual seed yield and apparent seed yield,and there was a significant interaction between row spacing and sowing rate.The actual seed yield and performance seed yield of Bromus inermis were the highest under H2D2 treatment,which were 1 804.38 kg·hm-2 and 3056.58 kg·hm-2,respectively.According to the path analysis,the number of spikelets,florets and effective tillers had a direct effect on the seed yield of Bromus inermis,and the panicle length had an indirect effect.The comprehensive analysis of grey correlation degree showed that the optimal row spacing for seed production of Bromus inermis was 30 cm and the sowing rate was 15 kg·hm-2.3.Row spacing and sowing rate had significant effects on soil urease activity,sucrase activity,catalase activity and alkaline phosphatase activity of Agropyron mongolicum,and there was a significant interaction between row spacing and sowing rate.Row spacing and sowing rate had significant effects on soil urease activity,sucrase activity,catalase activity and alkaline phosphatase activity of Bromus inermis,and there was a significant interaction between row spacing and sowing rate.The plant height,total tiller number,leaf-stem ratio,fresh yield,crude ash,neutral detergent fiber,acid detergent fiber and floret number were closely related to soil enzyme activity.Plant height,stem diameter,total tiller number,leaf area,dry-fresh ratio,hay yield,crude protein,crude fat,1000-grain weight and seed yield were closely related to soil enzyme activity. |
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