| Guided by ecological priority and green development,it was an inevitable choice for the development of modern agriculture and animal husbandry to adjust and optimize the agricultural planting structure,build a high-quality and efficient forage crop intercropping mode,and optimize farmland fertilization measures.The field experiment was carried out at the Northwest Naiman Desertification Research Station of the Chinese Academy of Sciences from 2020 to 2021,with forage oats and common vetch as the research objects.Forage reseeding was carried out after mowing at the filling stage of oat.A two-factor randomized block design was used.The planting pattern factors(P)included oat monoculture(SO),common vetch monoculture(SV)and oat and common vetch intercropping(IOV).The fertilization factors(F)included no fertilization(N),single application of chemical fertilizer(C),single application of bio-organic fertilizer(O)and combined application of organic fertilizer and chemical fertilizer(G).The effects of fertilization on water use characteristics,soil nutrient content,soil enzyme activity,multiple cropping forage yield and nutritional quality under different planting patterns were studied,and the related indexes of interspecific competition were analyzed.In order to clarify the effects of intercropping and fertilization on the utilization of water and soil resources,forage yield and nutritional quality of multiple cropping oats and common vetch,the suitable fertilization measures for intercropping of forage oats and common vetch in Horqin sandy land were determined.The results are as follows :1.The variation trend of soil water content in the vertical distribution layer of each planting pattern was consistent,and the overall shape was inverted “V”.The intercropping of oat and common vetch combined with organic fertilizer and chemical fertilizer treatment improved the water storage capacity of 0-60 cm soil,and the overall water content of the intercropping system was higher than that of the corresponding monoculture.The water use efficiency of IOV treatment was between SO and SV.Under the same planting mode,the water use efficiency of G treatment was higher than that of other fertilization treatments,and the efficient utilization of water was realized.In 2020-2021,IOV-G treatment was significantly higher than IOV-N treatment by 32.84% and 34.44%(P<0.05).2.Intercropping and fertilization significantly increased soil nutrient content and enzyme activity.From 2020 to 2021,the contents of soil total nutrients,available nutrients and organic matter in 0-20 cm and 20-40 cm soil layers were higher than those in no fertilization treatment,while the nutrient content in 0-20 cm soil layer was higher than that in 20-40 cm soil layer.Compared with IOV-N treatment,the contents of total nitrogen,total phosphorus,total potassium and organic matter in 0-20 cm soil layer of IOV-G treatment increased by 23.40%,25.00%,17.39%,82.14%,13.54%,10.95% and 29.27%,33.05%,respectively(P<0.05).The improvement effect of soil available nutrients in intercropping treatment was better than that in corresponding monoculture treatment.The activities of soil urease,invertase,alkaline phosphatase and catalase in IOV-G treatment were higher than those in monoculture oat and monoculture common vetch under the same fertilization treatment.Compared with no fertilization treatment,the activities of soil urease,invertase,alkaline phosphatase and catalase in intercropping combined with organic fertilizer and chemical fertilizer were significantly increased by 17.07%,17.24%,6.60%,7.35%,5.37%,10.38% and 2.36%,6.06%,respectively(P<0.05).3.Intercropping and fertilization significantly increased the aboveground fresh and dry grass yield of forage oats and common vetch.Under the treatment of organic fertilizer and chemical fertilizer(G),the fresh grass yield and dry grass yield of intercropping oats increased by 19.51%,23.78% and 4.34%,1.79%,respectively,compared with the corresponding monoculture treatment.The fresh grass yield and dry grass yield of intercropping common vetch increased by 13.26%,5.30% and 27.63%,34.12%,respectively,compared with the corresponding monoculture treatment.The land equivalent ratio(LER)of intercropping treatment was greater than 1,indicating that the intercropping of forage oats and common vetch had the advantage of increasing yield.According to the results of resource competitiveness and relative crowding coefficient,the results showed that common vetch had a stronger interspecific advantage than oat,which also laid a foundation for better playing the advantages of grass bean intercropping.4.Intercropping planting and fertilization treatment can improve the nutritional quality of forage oats and common vetch.The crude protein content of intercropping common vetch under G treatment was 8.05% and 8.89% higher than that of monoculture common vetch under the same level,and the crude protein content of common vetch was higher than that of forage oats under the same fertilization treatment.The crude fat content of intercropping oats under G treatment was significantly higher than that of N treatment by 11.61% and4.20%,respectively(P<0.05).The soluble sugar content of intercropping common vetch under G treatment was significantly higher than that of N treatment by 18.55% and 34.36%,respectively(P<0.05).The neutral detergent fiber and acid detergent fiber of intercropping oats under G treatment were 6.47% and 12.10% lower than those of monoculture oats under the same fertilization treatment,respectively.The relative feeding value of intercropping oats and intercropping common vetch under G treatment was significantly higher than that of N treatment by 39.18%,58.51% and 25.68%,55.46%,respectively(P<0.05).Fertilization treatment promoted the accumulation of nitrogen,phosphorus and potassium in forage.From2020 to 2021,the accumulation of nitrogen and phosphorus in forage was significantly increased by 152.19%,84.46% and 119.83%,75.95% respectively(P<0.05)in IOV-G treatment compared with IOV-N treatment.The accumulation of potassium in forage was the highest in IOV-C treatment,which was significantly increased by 79.77% and 81.38%respectively compared with IOV-N treatment(P<0.05).In summary,the intercropping of forage oats and common vetch combined with organic fertilizer and chemical fertilizer has the advantage of intercropping to increase production,increase forage yield,improve the nutritional quality of forage,and also improve soil fertility.Therefore,this model is suitable for promotion and application in Horqin sandy land and sandy soil area in eastern Inner Mongolia. |
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