Fertilizer placement experiments

Summary

The results are given of an investigation in the Netherlands, made over a number of years, on placement of fertilizers. This new method of application has been tested in field trials, in which placement has been compared with the usual method of broadcasting at certain increasing levels of fertilizer. The experiments relate to nitrogen, phosphate and potash on different kinds of crops and soils.

Generally speaking, it would appear that placement is better than broadcasting. The difference between the two methods of application can be represented by a factor indicating the ratio between the amounts of fertilizer giving the same yield for both. Nitrogen applied in bands is about 1.20 times as effective as broadcasting for cereals, potatoes and beets; phosphate for pulse crops 7.50, for maize 2.90, for cereals 2.45, for potatoes 1.90 and for beets 1.20; potash on river clay for cereals 3.65, for potatoes 1.00 at low pH and 1.60 at high pH and for beets 1.00. There are indications that the prevention of fixation and a better early growth as a result of the localisation of the fertilizer near the seed at an adequate depth are reasons why placement is successful.

The conclusions of de Wit with regard to the effect of placement are not corroborated. It appears that placement gives higher yields at light dressings, and at heavy dressings yields as high as broadcasting, whereas, according to de Wit, a favourable effect would be attained, as a rule, with light dressings and an unfavourable effect with heavy dressings.