SOIL AND PLANT ANALYSIS IN SOUTH-AFRICA

The development and current status in South Africa of soil and plant a nalysis for fertilizer advisory purposes is reviewed. Data obtained fr om governmental and private laboratories indicate that from 1966 to 19 92 the number of soil and plant samples analysed annually increased by approximately 180 % and 470 %, respectively. Plant analyses increased exponentially, but countrywide analysis of soil samples has not incre ased since 1982. An Inadequate soil test calibration base in many part s of the country, a scarcity of soil fertility researchers, and extrac tant and procedural differences among laboratories are considered to h ave been largely responsible. Advisory laboratories in those regions s upported by ongoing field research programmes have shown continual gro wth in analytical output and farmer demand. In these areas, the intens ity of soil sampling compares favourably with that in developed countr ies, but in other important cropping areas the intensity of sampling h as stabilized at about 90 ha sample-1. Over 80% of all plant analyses are conducted by laboratories serving high value deciduous and subtrop ical fruit industries, industries better able to make use of internati onally established analytical norms. While there is an urgent need for expanded soil test calibration research for annual row crops, it is d oubtful that this need will be easily satisfied. The availability of f unds for such research is declining and the publication demands on you ng researchers make long-term field studies decidedly unattractive.