ChileanJAR

Thirty nine soil samples of the province of Malleco are submitted to a pot-test trial with rye-grass. The applied formulations (N, NP and NPKS) are obtained from triple superphosphate (P), potassium sulphate (KS) and a solution of ammonium nitrate (N).
The yield comparison are made with the help of the fertility diagram, choosing an index of 100% for the complete fertilization treatment (nitrogen, phosphorus, potassium, calcium, magnesium, sulphur, boron, molybdenum,· zinc, copper and manganese) .
The treatment NPKS and complete fertilization resulted in equal yields. Also, similar yields are obtained from treatments NP and the incomplete fertilization treatment due to a shortage of potassium. On the otherhand, the line of fertility in the treatment without phosphorus always surpasses the fertility determined by the corresponding line of N.
The diagnosis of nutritional deficiencies previously determined with the technique of the missing element, is crearly confirmed.
The addition of nitrogen, phosphorus, potassium, and sulphur to soils, correets the actual low fertility, and keep it high. Theparameters of the line of production log Y = mX + lag A with each soil, is caleulated for the three fertilizer formulations.