Fertility study on a campo cerrado soil

Abstract

In a greenhouse experiment with corn the response to mineral fertilizers (NPK, lime and micronutrients) was analized by three different experimental designs to determine how the responses to fertilizers as measured with incomplete factoriais compared with the complete factorial. The present papar represents also a contribution to the evaluation of the fertility of a campo cerrado soil from Goiás, Brazil. A complete 2° factorial analysis was done as well as two additional fractional factorial analysis corresponding to the two groups: —NPKCaM and +NPKCaM. The interaction of the higher order was confounded because of the fractionization in two groups. The best results were obtained from the fractional factorial analysis whose NPKCaM interaction was not confounded, since its standard deviation came out to be smaller. The same analysis was able to give us all the information about the single effects and main interactions, and according to its results the main needs of the soil in question are lime, phosphorus and nitrogen, the same deficiencies a previous soil analysis had detected. Neither micronutrients nor potassium responses were found to be significant.