The maize microplot method of soil testing

Abstract

A simple field method of soil testing is described that can be completed in less than a month. The plotting is a 3 x 3 x 3 factorial design, with 2 x 2 ft (60 x 60 cm) plots in areas separated by equally spaced spaces. The method consists of the application of standard N.P.K. fertilizers at levels 0, 1, and 2, the unit of application being 3 hundredweight per acre (336 lb per acre) of ammonium sulfate, 2.5 hundredweight per acre (280 lb pa) of single superphosphate, and 1 hundredweight per acre (112 lb pa) of potassium sulfate. The indicator plant is corn, which is harvested after four weeks of growth and immediately weighed. The best fertilizer treatment is the one giving the highest yield of leaf material. The results are plotted in a diagram. An example of how the results are expressed is given. The experiment can be replicated by adding a micronutrient mixture or a calcium-based amendment to each plot to evaluate the effects of these additions.