COMPARISON OF IRRIGATION SCHEDULES FOR PROCESSING TOMATOES BASED ON SOIL MOISTURE MEASUREMENT AND CLIMATOLOGICAL DATA

Two methods of scheduling irrigation of processing tomatoes were investigated in 1979, 1980 and 1981. In each year, irrigation schedules necessary to prevent the available soil moisture (ASM) from falling below 50% were similar, whether determined from measurement of soil moisture using a neutron probe or deduced from climatological data which included maximum and minimum air temperature, duration of bright sunshine and effective rainfall during the growing season.

The climatological method was as accurate as the soil moisture method but more convenient and less expensive. By use of the proper values of available moisture-holding capacity of soils and rooting depth of crops, the climatological method can be applied to different crops in different areas. The data required to utilize the climatological method are readily available from local weather stations or can be measured directly if necessary.