Title: EFFECT OF MINERAL FERTILIZERS AND MANURES ON THE PHOSPHORUS CONTENT OF A CLAY SOIL AND ON CROP YIELDS AND QUALITY IN A LONG-TERM CROP ROTATION
Abstract: Investigations of a long-term rotation experiment, to which mineral fertilizers and manures have been added for 38 years, show that the total inorganic and extractable phosphorus content of the soil has been increased by phosphate fertilizers. The organic phosphorus fraction was not affected. The extractable phosphorus content of the phosphate treated plots was found to be inversely related to the soil inorganic carbon content.Moving 12-year average yields of wheat first crop, and barley third crop in the rotation, showed the response to phosphorus is apparent only in the first year, with no residual effect on crops due to the increased soil phosphorus content. Mineral fertilizer nitrogen had no effect on the yield of the first crop, but a residual effect was apparent on the third crop. Barn manure increased yields of both crops, presumably due to the effect of phosphorus in barn manure on the first crop and the nitrogen on the third crop. Red clover as a green manure slightly decreased yields of wheat in the first year but increased yields of barley in the third year. A depressing effect on the first crop, presumably due to a nitrogen deficiency, was caused by grass plowed down as green manure but a slight increase in yields of the third crop was noted.Application of 47 pounds of nitrogen for wheat on summerfallow significantly increased the protein content of six wheat crops sampled. Variations in the protein content of wheat between years is presumably related to climatic conditions.
Publication Year: 1962
Publication Date: 1962-02-01
Language: en
Type: article
Indexed In: ['crossref']
Access and Citation
Cited By Count: 9
AI Researcher Chatbot
Get quick answers to your questions about the article from our AI researcher chatbot