| A single-factor randomized group design was used to study the effects of different sowings of Lablab purpureus(L.)Sweet(0 kg·hm-2、22.5 kg·hm-2、45.0 kg·hm-2、67.5 kg·hm-2、90.0kg·hm-2)and Sorghum dochna(Forssk.)Snowden on the grassland yield,forage quality and soil nutrients in Ningxia rain fed area.The results of the study are as follows:(1)Different mixed sowing treatments had a significant effect(P<0.05)on the plant height,stem width and node strength of Sorghum dochna(Forssk.)Snowden,among which,the plant height,stem width and node strength of 5-7 nodes of Sorghum dochna(Forssk.)Snowden were better than those of partial mixed sowing treatments.There were significant differences(P<0.05)in leaf-stem ratio,dry-fresh ratio,fresh yield and hay yield between the different sowings of Lablab purpureus(L.)Sweet and Sorghum dochna(Forssk.)Snowden mixed treatments.The grey correlation analysis showed that Sorghum dochna(Forssk.)Snowden grassland had the best production performance when single sown.(2)The crude protein,ether extract,crude ash,NDF,ADF and relative feeding value of mixed forage were significantly affected by different mixed treatments(P<0.05),and the crude protein,crude ash and relative feeding value of mixed forage were higher than those of single-seeded treatment.The gray correlation analysis showed that the forage quality was best when sowed at 67.5 kg-hm’2 of Lablab purpureus(L.)Sweet mixed with Sorghum dochna(Forssk.)Snowden.(3)There were significant differences(P<0.05)in dry matter,crude protein,ether extract,crude ash,NDF,ADF and relative feeding value of forage silage after different mixed treatments,and significant differences(P<0.05)in fermentation indicators such as pH,ammonia nitrogen content lactate,acetic acid,propionic acid and butyrate between treatments.Gray correlation analysis showed that forage silage quality was best when sown at 22.5 kg·hm’2 of Lablab purpureus(L.)Sweet mixed with Sorghum dochna(Forssk.)Snowden.(4)The nutrient content of 0-20 cm soil was significantly different(P<0.05)between the different treatments,among which the highest content of alkaline nitrogen,quick-acting potassium,total phosphorus and quick-acting phosphorus was found in the mixed sowing of 22.5 kg·hm-2 Lablab purpureus(L.)Sweet and Sorghum dochna(Forssk.)Snowden.The combined analysis showed that the sowing of 22.5 kg·hm-2 of Lablab purpureus(L.)Sweet mixed with Sorghum dochna(Forssk.)Snowden was effective in improving soil fertility.The results of the analysis showed that the productivity of the single-seeded grasses of Sorghum dochna(Forssk.)Snowden was higher than that of Lablab purpureus(L.)Sweet and Sorghum dochna(Forssk.)Snowden;Lablab purpureus(L.)Sweet sowed at 67.5 kg·hm-2 and Sorghum dochna(Forssk.)Snowden mixed forage was the best;Lablab purpureus(L.)Sweet sowed at 22.5 kg·hm-2 and Sorghum dochna(Forssk.)Snowden mixed forage silage was the best;and soil fertility was improved.Therefore,in the production of Sorghum dochna(Forssk.)Snowden forage in the Ningxia rain fed area,different planting methods can be chosen according to different needs. |
