| With the adjustment of agricultural production structure and the development of agriculture and animal husbandry in China,the planting area of Medicago sativa L.will be further expanded.Plant density and phosphorus application play an important role in the industrialization of alfalfa industry.Because the leaves are very sensitive to plant density and the supply of phosphorus,the amount of nutrients in the leaves can reflect the appropriate degree of sowing amount,the availability of soil nutrients and the level of supply.For a long time,the research on the yield and quality of Medicago Sativa L.is more concentrated on the whole plant,while the study of the stratification is less,especially in the stratified leaves.In scientific research,the leaves of Alfalfa with different utilization value can be studied by the stratified harvest method of leaf.Therefore,it is of great significance to determine the seeding rate and the amount of phosphorus by studying the plant characteristics and nutrient content of alfalfa leaves in different layers.A field experiment of Medicago satial L.Gannong No.3 which was seededin lanzhou city qilihe district merchant mountain of lanzhou institute of animal husbandry and veterinary medicine,China academy of agricultural sciences comprehensive experimental station for alfalfa planting density and P fertilizer field experiment,the alfalfa faults different growth period,different time,different layers blade change law of botany characteristics and characteristics of chemical measurement.The results as follows:（1）with the increase of plant density,the ratio of leaf length,leaf width,leaf area,leaf number per branch,leaf fresh weight,leaf dry weight and the ratio of dry weight in leaf decreased at the same growth stage.Ratio of leaf length width increased with the increase of density in Branching stage and budding stage,decreased in early flowering stage（P<0.05）.The effect of density on fresh weight and dry weight of middle and lower leaves was not significant（P>0.05）.In the same plant densities,leaf length,leaf area,leaf width showed early flowering>bud stage>branching stage>,leaf fresh dry weight ratio showed branching branching stage>bud stage>flowering stage.With the increase of plant density,the length of leaf,leaf width leaf area,number of leaf per branch,leaf fresh weight and dry weight were increased.The order of the leaf length,leaf width,leaf area,leaf number per branch,leaf fresh weight and leaf dry weight were the first crop>the second crop>the third crop in 2015.The order of the number of leaf per layered branch was upper layer>middle layer>lower layer,and the order of average stratified leaf area,leaf fresh weight,and leaf dry weight were middle layer>upper layer>lower layer.The plant density had a greater impact on the lower leaf area of each growth stage,and the low density treatment was significantly higher than that of high density treatment（P<0.05）.In leaf fresh weight and leaf dry weight in the mean and upper layer,the low density treatment was significantly higher than that of high density treatment（P<0.05）.（2）With the increase of P content in the same periods,leaf length,leaf width and leaf area,single compound leaf number,fresh weight,dry weight,fresh dry weight ratio were increased,but there is no obvious regularity in the fresh dry ratio of leaves.the impact on the lower leaf on area of P supply is greater than the upper and middle layer.Under the same amount of p supply,the order of leaf number per branch was middle>upper>lower in branching stage;the order of leaf number per branch was the upper>the middle>the lower in Early budding period and flowering.The effect of P on the lower leaf number per branch was greater than that in the upper and middle layer（P<0.05）.In the process of alfalfa growth,the order leaf length,leaf width,leaf area size of early flowering stage>budding>branch under the same planting density treatment,,leaf fresh weight and leaf dry big small performance for the early flowering stage>budding>branch.With the increase of P content in the same crop,leaf length,leaf width,leaf area,the number of single branch compound leaves,leaf fresh weight and dry weight were increased.The size order of leaf length,leaf width,leaf area in different crop of were the second crop>the first crop>the third crop in 2015.The order of fresh weight and dry weight of leaf in four crop was upper>middle>lower.（3）Under the effect of plant density and phosphorus supply,the order of leaf length、fresh weight of leaf and dry weight of leaf in different development stages,were early flowering stage>budding stage>branching stage;the order of leaf width,leaf area,length/width of leaf were early budding stage>early flowering stage>branch;the order compound per branchwas early flowering stage>branching stage>budding stage.The size order of leaf length,leaf width,leaf area were the upper>the middle>the lower.Under the effect of plant density and phosphorus supply,effect of leaf length,leaf width,length/width of leaf was branching stage>budding stage>early flowering,and each time there is always the top>the middle>the lower.On the performance of leaf area was early stage>flowering stage>budding branches and the performance of compound leaf number of single branch was early flowering stage>branching stage>budding stage.leaf area,leaf fresh weight,single compound leaf number were bigger in plant density and phosphorus supply under the joint action of 368 million strains·hm-2×120 kg·hm-2,263 million strains·hm-2×120 k·hm-2（P<0.05）.（4）with the increase of plant density,C,N,P content and chlorophyll content of leaf in each layer were lower,the size order of C,N,P content and chlorophyll content of leaf were upper>middle>the lower.Under the same planting density,the order the content of C,N and P of middle and lowerr layer in different growth period was branching stage>budding stage>early flowering stage.The size order of chlorophyll content was early flowering stage>budding stage>branching stage.The order of the concentrations of C,N and P in each crop in 2015 year were first crop>second crop>third crop.The content of C:N,C:P of the layers of leaf increased in different crop and different periods with the increase of plant density,N:P showed a trend of rising slightly first.and decreased significantly.the size of the order C:N,C:P of alfalfa leaf in different crop was the first crop>the second crop>the third crop>,N:P size order was the first crop>the second crop>the third crop.The size of the order of C:N,C,P,N:P was early flowering stage>budding stage>branch Stage.（5）with the increase of P content,C,N and P content and chlorophyll content of leaf in the same growth period were rising.With the increase of P supply,C:N increased,C:P,N:P decreased（P<0.05）.P fertilizer especially bigger influence on the upper layer.In different growth period,the size order of C,N,P content in middle and lower layer leaf was branching stage>budding stage>early flowering.C,N,P content and chlorophyll content of leaf in 2015 were the first crop>second crop>third crop.The size order of C:N,C:P and N:P in each crop in 2015year was the first crop>the second crop>the third crop.（6）Under the effect of plant density and phosphorus supply,the size of the order of C,N,P content and chlorophyll content in each layer in the same periods ofwere upper layer>middle layer>lower layer;the size order of C,N and P in each growth period was early stage>budding stage>early flowering branches and the order of chlorophyll content was early flowering stage>budding>branch.The size of the order of C content each crop was the second crop>the first crop>the third crop in 2015,the size of the order of N,P content was the second crop>the third crop>the first crop in 2015 and the size of the order of chlorophyll content was first crop>the third crop>the second crop in 2015.Each reproductive period each blade and crop leaf C,N,P content and chlorophyll content was higher,respectively for 368 million stem·hm-2×120 kg·hm-2,368 million stem·hm-2×160 kg·hm-2,263 million stem·hm-2×120 kg·hm–2. |
PDF Full Text Request