Publication Date

1985

Location

Kyoto Japan

Description

Our 3-6-year fertilizer experiments aiming at the foundation of a water saving grassland management technology showed various crops in different years. In order to find out the reasons, in 1973 an experiment of several years was started with the mixture of 6 grasses and 2 papilionaceae. The results of the years between 1974-1982 were classified. We established that among our conditions precipitation has a great influence on the seasonal and annual crop of grassland. From the point of view of precipitation, the word "year" is considered as a period between 16th October and 15th October. Temperature has an effect, too, with the same precipitation quantity the change of temperature modifies the crop. If water supply is optimal, 1 °C heat modifies the dry matter crop of grassland with 2,5 t/ha. The rate of the two climatic factors is optimal at 0.20-0.25 mm/1 °C. If precipitation is less, a more water saving technology is used, if more, then a more water wasting one is suitable (between the two, a neutral technology from the viewpoint of water production is suitable). Less precipitation than 0,2 mm/°C means a relative shortage of water. Irrigation is economical up to the rate of stopping a relative shortage of water, because with irrigation a water saving technology is compulsory all the time.

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The Effect of the Rate of Precipitation and Heat on the Crop of Grassland

Kyoto Japan

Our 3-6-year fertilizer experiments aiming at the foundation of a water saving grassland management technology showed various crops in different years. In order to find out the reasons, in 1973 an experiment of several years was started with the mixture of 6 grasses and 2 papilionaceae. The results of the years between 1974-1982 were classified. We established that among our conditions precipitation has a great influence on the seasonal and annual crop of grassland. From the point of view of precipitation, the word "year" is considered as a period between 16th October and 15th October. Temperature has an effect, too, with the same precipitation quantity the change of temperature modifies the crop. If water supply is optimal, 1 °C heat modifies the dry matter crop of grassland with 2,5 t/ha. The rate of the two climatic factors is optimal at 0.20-0.25 mm/1 °C. If precipitation is less, a more water saving technology is used, if more, then a more water wasting one is suitable (between the two, a neutral technology from the viewpoint of water production is suitable). Less precipitation than 0,2 mm/°C means a relative shortage of water. Irrigation is economical up to the rate of stopping a relative shortage of water, because with irrigation a water saving technology is compulsory all the time.