Effects of Meteorological Factors and the Yield of First Crop of Tea Leaf

Abstract

The relations between meteorological factors and the yield of first crop of tea leaf were analyzed by means of correlation coefficient, path coefficient and multiple regression. The data of meteorological factors were the pentad mean of maximum and minimum air temperature and the pentad sum of precipitation from September to April in past 20 years.
1. As a result of correlation analysis, the coefficient of the pentad mean of maximum and minimum air temperature and the pentad sum of precipitation changed minus to plus from September to October, plus to minus from December to January and minus to positive from March to April, respectively. It was calculated high positive correlations between yield and meteorological factors in Autumn and Spring, and slightly high negative correlations in Winter.
2. As a result of path coefficient analysis, yield was highly related to both air temperature of March, October and September. and precipitation from March to April and from September to October. Therefore the weather of Autumn and Spring were very important to the yield of the first crop.
3. On the basis of direct effect of every month in path coefficient analyses, the, period from September to April was divided three periods with regard to air temperature ; namely, from mid September to mid November, from late November to the first half of April and in the last half of April. And it was divided the four periods with regard to precipitation ; namely, from September to December, from January to mid March, from late March to the first half of April and in the last half of April.
4. From the relations between meteorological factors and the yield of first crop, following four phases were thought as the growth phase of tea plant from autumn to spring ; 1) the developing phase of autumn bud from October to the beginning of November, 2) the phase being related to cold weather from mid November to February, 3) the preparatory phase of new shoot from March to the first half of April, and 4) the growing phase of new shoot in the last half of April.
5. The yield was estimated by the followimg multiple regression formula equation.
Y=970.2562+78.1301X₁-11.9157X₂
+36.0315X₃-50.6482X₄-28.8750X₅
-14.5604X₆-4.9906X₇-10.8755X8
-43.0096X₉+15.2774X₁0+1.1313X₁1
Y : the yield of first crop of green leaf in tea crop (kg/10a),
X₁ : 4th pentad mean of maximum air temperature in January,
X₂ : 6th pentad mean of maximum air temperature in January,
X₃ : 3rd pentad mean of minimum air temperature in January,
X₄ : 4th pentad mean of minimum air temperature in January,
X₅ : 4th pentad mean of maximum air temperature in February,
X₆ : 6th pentad mean of maximum air temperature in February,
X₇ : 3rd pentad sum of precipitation in January,
X₈ : 3rd pentad sum of precipitation in February,
X₉ : 4th pentad mean of maximum air temperature in March,
X₁0 : 1st pentad mean of minimum air temperature in March,
X₁1 : 2nd pentad sum of precipitation in March.