SAMPLING SOILS FOR FERTILIZER AND LIME RECOMMENDATIONS
Proper soil sampling is crucial for
good soil test results. soil sampling is an indispensible operaition towards profitable management of land.
fertilizer and lime
recommendations are based on soil sample results. It is advisable to sample uniform areas seperately. Areas of uniform characteristics must be delineated for sampling. the heterogenesity can be a result of productivity, topography, texture, drainage, color of top soil and past management. Twenty (20) soil cores are adequate to make a well mixed sample to obtain consistant laboratory test results. Appropriate soil sampling tools must be used such as a screw auger and a spade can be used. The soil sampling depth must be as deep as the ploughing depth, however subsoil samples are crucial for appropriate fertilizer and lime recommendations. The zigzag sampling pattern avoiding fertilizer bands has proved to provide an excellent representative composite sample. A pint of the well mixed soil sample is required for analysis. Soil samples may be taken anytime during the year. Soil sampling must be done once every 3 years but sandy soils may require frequent sampling. Intense soil sampling is required to develop nutrient management maps. The main approach is grid sampling for collecting soil samples where the objective is to develop a map of soil test values for a field. To develop the most appropriate lime and nutrient recommendation for the crops to be grown the information sheets provided by the testing laboratory must be filled and sent together with the samples. All significant management practices must be indicated because they may affect the recommendations. It is important to send the composite soil sample and the information sheet to a reliable soil testing laboratory.