| Alfalfa industry has developed rapidly in erdos area recent years, the planting area is graduallyexpanding,there is nearly 500,000 acres of alfalfa. however there are many alfalfa varieties planted inthis area, including introduced alfalfa varieties, study on the adaptability of some introduced alfalfavarieties has not been carried out,resulting in the failure of alfalfa estabilish and the business loss ofenterprise.At the same time alfalfa harvest is usually at full-bloom stage, causing the lower anutrientvalue. These factors constrain the sustainable development of the local alfalfa and livestock industry.This study was carried at country forage industrialization technological system erdos comprehensiveresearch station. Different alfalfa varieties productivity were observed in three growing season from2012 to 2014.The yield and nutrition content of alfalfa in different cutting stages were also determined,at the same time the Chlorophyll Fluorescence parameters and alfalfa leaf water potential wasdetermined by PEA at June 28 th and July 25 th respectively,we also observed alfalfa net photosyntheticrate by LI-6400 XT. We aim to choose suitable alfalfa varieties and better alfalfa harvest time to guidelocal alfalfa industry.The main results were as follows:1. Considering the production and stability of dry yield, kangsai, WL319 HQ and zhongmu 1hao arethe suitable alfalfa varieties in ordos area. The nutrient content of the first cutting changed withdeveloping stage,the concentrations of CP decreased,while NDF and ADF content increased. alfalfaharvest time should be at budding stage. Nutritional value of different alfalfa cutting shows the thirdcutting>the first cutting>the second cutting.2. Fluorescence parameters analysis indicated that Diurnal variation of the initial fluorescence wassimilar among alfalfa cultivars, showing a unimodal curve. there are two types in Maximumfluorescence changes, one is "the Valley", including zhunger and WL319 HQ, another type is the doubledip pattern, including zhongmu1 hao, caoyuan3 hao, kansai, Crown, WL343 HQ, and caribou.Comprehensive analysis of alfalfa fluorescence parameters indicated zhongmu1 hao and WL319 HQ isbetter. Correlation analysis showed Fv/Fm was significantly negative negative correlation withphotosynthetic active radiation3. During the summer, the diurnal variation of water potential of alfalfa leaf is " valley" curve, thereare not difference in varieties, but the decline range differ with different alfalfa varieties, the rankfrom large to small is caribou > Crown > zhongmu1 hao > kansai > WL319HQ> WL343HQ> caoyuan3 hao > zhunger. Zhunger alfalfa and caoyuan3 hao water potential changes to a less extent, they areable to endure summer drought stress environment in some extent. photosynthetic active radiation andtemperature were significantly negative correlation with alfalfa leaf water potential. 10 ~ 20 cm soilmoisture were significantly positive correlation with alfalfa leaf water potential.4. the net photosynthetic rate of kangsai is the largest. By analysis of variance, the netphotosynthetic rate of kangsai was significantly higher than other alfalfa varieties(P<0.05). the alfalfaregrowth production was closely related to the net photosynthetic rate. |
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