| Two-factor split area design was used,and two alfalfa varieties were mixed at 1:1.The main factor(A1:13.5kg·hm-2,A2:18.0kg·hm-2,A3:22.5kg·hm-2)and the mixed sowing mode were sub-factor(B1:unicast,B2:peer mixed sowing,B3:1+1 rows mixed,B4:1+2 rows mixed,B5:1+3 rows mixed)In order to provide theoretical basis for the establishment of "high standard-fine" alfalfa artificial grassland,the development of resource allocation and efficient utilization of high-yield and high-quality alfalfa in Ningxia Yellow River Irrigation Area.The main findings are as follows:(1)the planting amount had a very significant effect on the plant height(P<0.01),and with the increase of the planting amount,the alfalfa plant height increased first and then decreased.The third seeding amount was 13.5 kg·hm-2 and the growth rate was significantly faster than other seeding amounts(P<0.05).There was a significant difference(P<0.05)in the effect on the average stem diameter of four stubble alfalfa,and the maximum stem diameter was 13.5kg·hm-2.The effect on the leaf area of the first crop of alfalfa was significantly different(P<0.01),the leaf area tended to decrease with the increase of seeding amount,and it had a significant effect on the ratio of the third crop of alfalfa(P<0.05).The total production of alfalfa increased first and then decreased with the increase of sowing amount.(2)the influence of mixed planting mode on the plant height of three or four crops of alfalfa and the average plant height of the four crops was significantly different(P<0.05).The effects on the number of branches per m2 of the first,fourth and fourth stubble of alfalfa were significantly different(P<0.01).The leaf area of the second and third crops of alfalfa was significantly different(P<0.01).For the first alfalfa hay yield difference was significant(P<0.05),monoculture hay yield was lower than mixed planting,and the highest alfalfa hay yield was 1+3 mixed planting.(3)sowing amount × mixed sowing mode had a very significant effect on the plant height of the first and fourth stubble(P<0.01),and the highest plant height was that of the first treatment A1B5(seed amount:13.5 kg·hm-2,model:1+3 mixed sowing).It had a very significant effect on the average four stubble alfalfa stalk diameter(P<0.01),and the stalk diameter was A2B5(sowing amount:18.0 kg·hm-2,mode:1+3 interrow mixed sowing).There was a significant effect on the number of branches per m2 of the first,fourth and fourth stubble alfalfa(P<0.01),and A1B2(sowing amount:13.5kg·hm-2,mode:mixed sowing in the same industry)was the largest number of branches per m2 of the fourth stubble alfalfa.(4)there was no significant difference between different sowing amounts and nutritional quality of alfalfa(P>0.01).The influence of mixed seeding mode on NDF content was significantly different(P<0.05).The content of mixed seeding NDF was lower than that of unicast.The mixed seeding with the lowest NDF content was 1+3 rows.The effect on dry matter content was significantly different(P<0.05),the dry matter content of unicast was lower than that of mixed seeding,the dry matter content of mixed seeding between 1+2 rows and 1+3 rows was significantly higher than that between the same row and 1+1 row,and the dry matter content of mixed seeding between 1+2 rows was the highest.Sowing amount ×mixed sowing mode showed significant differences in the interaction between dry matter,ADF,starch and RFV(P<0.05).The content of RFV was the highest and the content of ADF was the lowest in A2B5(sowing amount:18.0kg·hm-2,mode:1+3 rows of mixed sowing),the starch content of A2B3 was high,and the dry matter was the highest in A3B4(sowing amount:22.5 kg·hm-2,mode:1+2 rows of mixed sowing).Through principal component analysis and grey relational degree analysis of alfalfa production performance and nutritional quality,it is concluded that A2B5(sowing quantity:18.0 kg·hm-2,mode:1+3 mixed sowing)has the best comprehensive performance,and it is suggested to adopt this mode to plant alfalfa in the irrigation area of Yellow River in summer. |
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