IRRIGATION DEMAND OF TOMATO ACCORDING TO THE RESULTS OF THREE DECADES

Yearly changes in temperature and precipitation in Hungary are varied. The authors have been examining the water turnover, water demand of the tomato and the impact of water supply and temperature on the yield for 31 years.

In the present study they evaluated the yield per year and per treatment comparing four different water supply treatments of K.42 variety between 1962 and 1976 and of K.Jubileum between 1977–1992 with 15 and 16 year experimental averages. Weather in each year similarly influenced the crop amount experimental average was 43 and 42 tonn/ha, its dry material yield (2478 and 2524 kg/ha) and the number of yield (679 000 and 536 000 pcs/ha) under regularly irrigated as well as non-irrigated conditions. It was stated that on sandy soils with bad water reserving ability in order to reach big yield.

• regular irrigation is needed in 55 % of years;
• one well-scheduled irrigation is enough in 20 % of years;
• the natural water supply is enough in 5–7 % of years;
• in 20 % of years the irrigation has no effect due to other impacts (late spring frost, cool year, etc);
• in 10 % of years the yield is medium, and
• in 10 % it is very small - disregarding the water supply.

The effects of each year also expressed in crop components.