Comparisons of anhydrous ammonia with solid ammonium nitrate for spring barley and winter wheat 1967–70

Summary

Fourteen trials on spring barley and eleven on winter wheat, grown in the east of Scotland, compared the effects on yield of liquified anhydrous ammonia and solid ammonium nitrate at various levels of application.

For grain yield, the optimum N level in these trials was about 100–113 kg N/ha. The object of including in the trials N input levels higher than optimum was attained. Yield response to the two forms of N was similar for both wheat and barley at the different N input levels.

Winter injection of anhydrous ammonia was less efficient than spring application. Injection of anhydrous ammonia into young wheat resulted in frequent reduction of plant population and, on occasion, loss of yield.

At equivalent rates, anhydrous ammonia caused less lodging than ammonium nitrate; it also appeared to be less readily leached from the soil. Ammonium nitrate gave more rapid early growth and this led to a greater proneness to leaf disease.

Considering the complexity of storage and injection equipment required to handle anhydrous ammonia, it is questionable if these agronomic advantages justify its use on cereals where rates of use do not also confer the benefits of cheaper unit cost of nitrogen.