Study On The Relations Between Growth Characters Of Alfalfa And Temperature

This paper carried out research on growth characters of alfalfa and temperature from two aspects: height and stem diameter by using the model of logistic to analyze the relation between the two aspects and temperature.Results were as follows:1.The first cutting required 61 days and the daily average temperature changed from 22℃to 9℃, the second cutting required 21 days, the average temperature changed from 21℃to 26℃, the curve of height growth of the first cutting fluctuated compared to the second cutting.2. Logistic model characteristic parameters of the high growth indicated: the average value of height growth potential (K) of the first and second cutting were:94.1504cm,65.0399 cm.The height growth potential of the first cutting was higher than the second cutting by 30.1105 cm.3.The curve of height growth rate showed that it required 35 days from reviving period to the maximum growth rate (vmax ) of the first growth season appeared , it required about 16 days from the first cutting to the maximum growth speed (vmax) appeared ,which was shorter than the fisrt season by 19 days.4.The first cutting entered the quick growth period needed 10.72 days after the reviving period ,the second cutting took 0.83 days shorter than the first cutting by 9.89 days.The average of maximum growth rate (vmax) of the first cutting was 0.92cm/d,The average of maximum growth rate(vmax) of the second cutting was 3.03cm/d,2.11cm/d than the first cutting.The quick growth period ( ?t ) of the first cutting was 67 days, the second cutting was shorter by13 days, compared to the first cutingg .The average speed of the quick growth period of the first first cutting was 1.07cm/d,the average speed of the quick growth period of the second cutting was 3.77cm/d.5. Logistic model characteristic parameter of height growth and the accumulated temperatures above 5℃indicated:the average value of height growth potential (K) of the first and secondcutting were 71.3013cm and 67.7406cm, the first cutting was higher than the second cutting by 3.5607cm .The average of maximum growth rate (vmax) of the first cutting was 0.064cm/℃·d. The average speed of the quick growth period (v max) of the first cutting was 0.08cm/℃·d.The average of vmax and v max of the second cutting was 0.14cm/℃·d and 0.18cm/℃·d.6. Logistic model characteristic parameter of stem diameter growth and the accumulated temperatures above 5℃indicated that the average value of vmax of the firstcutting was 0.0016cm/℃·d. the average value of v max was 0.0069cm/℃·d, it required 216.41℃·d accumulated temperature (k0) ,the accumulated temperature of the logarithms growing period ( ?k ) was389.90℃·d.The average value of vmax,v max,k0,?k of the second cutting was followed : 0.0013 cm/℃·d, 0.0054 cm/℃·d, 34.56℃·d, 68.26℃·d.7. Analyse of the correlation coefficient and the paths correlation showed that: the accumulated temperatures above 5℃was the major climatic factor upon the yields of alfalfa,the followed was sunshine duration. multiple aggregation showed that there was significant positive correlation between yield and climate factors.