Response of winter rye to hyperphosphate and superphosphate

The response of winter rye to hyperphosphate and superphosphate was studied in two field trials, previously carried out for 6 years with other crops. The amount of phosphorus applied to the rye crop in these two fertilizers was 66 kg/ha, the earlier applications amounted to 100 kg/ha. The superiority of superphosphate as a source of phosphorus to winter rye was in the both trials more or less distinct throughout the growing period, as could be shown by the dry matter weight and phosphorus uptake of rye plants from May to the middle of July, and by the actual yield results. It is assumed that an important cause for the superiority of superphosphate may be found in the fact that plants feeding on it are able to grow sprouts vigorous enough to endure the hard conditions of overwintering in our country. Particularly, the devastation caused by the low temperature parasitic fungi was in these two trials distincly decreased by the treatment with superphosphate. The positive effect of hyperphosphate was markedly lower. The soil analyses indicated that the hyperphosphate phosphorus occurred both in the more acid fine sand soil and, especially, in the less acid organic soil mostly in the calcium bound form, whereas the effect of superphosphate could be detected in the somewhat higher test values for aluminum and iron bound phosphorus