Effects Of Different Cutting Heights On Vegetable Qualities For 11 Alfalfa Varieties

Alfalfa(Medicago sativa L.)is traditional forage which has high protein content and rich in nutritional value.However,in reviving stage of alfalfa in northern China in spring,people often pick alfalfa sprouts as natural green vegetable to eat.In order to develop this alfalfa haruna,we chose 11 alfalfa varieties(Magna 551,Magnum VI Wet,Magnum VI,Multifoliate Alfalfa Dormancy 6,Multifoliate Alfalfa Dormancy 4,3010,AC Caribou,4010,Golden Empress,Ameistand 201T and spyder),which growth phase is in the second years,and they are cut with the different growing heights(8cm,12cm,16cm and 20cm)after turning green.Observing the relative water content,stem-leaf ratio,fresh-dry ratio,leaf area,fresh grass yield and stem-leaf CP of alfalfa aboveground,determining the roots of CP,starch and soluble sugar and other indicators to ascertain the effects of different cutting heights on alfalfa haruna growth,yield and nutrient content of the material,and study the impact of this low altitude,multi-frequency cutting in spring on alfalfa latter growth.The results show as following:(1)The growth tendency of 11 alfalfa varieties are similar,the period of seedling establishment of Magna 551,Magnum VI Wet and Magnum VI are earlier than others,so their growth heights are higher than other varieties.At the same time,Magna 551,Magnum VI Wet and Magnum VI are respectively cut 7,6 and 5 times under the cutting height of 8cm,12cm and 16cm,and one time more than other eight varieties.At the cutting height of 20cm,Magna 551and Magnum VI are cut 4 times,and also one time more than other varieties,but Magnum VI Wet is cut 5 times and 2 times more than other eight varieties.(2)The relative water content and fresh-dry ratio of 11 alfalfa varieties increase with the rising of cutting heights of the first cutting and decreasing at the cutting height of 20cm in the second time.When cutting went in the third time,except Magnum VI Wet and Magnum VI continue to increase,most of the other varieties are approximately at the cutting height of 8cm and 20cm.This shows that three times are the maximum cutting frequency of alfalfa as haruna.(3)When cutting heights increased,the stem-leaf ratio of 11 alfalfa varieties gradually reduced after three times cutting,which shows that the higher the growth is,the lower the alfalfa leaf proportion will be.However,leaf areas present the trend of increase,and compared with three times cutting,the leaf areas of the third cutting is lower than the previous two times.That is to say,frequently cutting is not conducive to the growth of leaf blade and will affect the accumulation of nutrients(4)When cutting height is under 20 centimeter,the higher the cutting height is and the higher the growth the more of total fresh grass field.Comparing the average fresh grass field,we can see that average fresh grass field increased with the rising of cutting height,that is to say,frequent cutting is not conducive to accumulation of alfalfa dry matter.(5)With the cutting height increased,the crude protein content of alfalfa's stem-leaf gradually reduced,and the crude protein,soluble sugar and starch content of root increased.It is to say,high height of cutting inhibits the accumulation of plant nutrients,accelerates the accumulation of the root nutrients.In addition,the root nutrients accumulation of 3010 and Ameistand 201T at 8cm is higher than 12cm,so they have stronger resistance to low cutting heights.(6)When alfalfa is used as haruna in spring,the most suitable cutting frequency is three times,and the three appropriate heights should be controlled within 20cm,16cm and 8-12cm.(7)The variety Multifoliate Alfalfa Dormancy 6 and 4010 as Haruna alfalfa is outstanding in its good taste;If turns to nutritional value,Ameistand 201T is a good choice;If considering these two aspects,Magna 551,Magnum VI Wet,Magnum VI,3010 and Golden Empress will be the best choice.