The residual effect of alfalfa cropping periods of various lengths upon the yield and protein content of succeeding wheat crops
1935
Metzger, W.H.
An attempt has been made at the Kansas Agricultural Experiment Station to measure the residual effect of alfalfa cropping upon yield and protein content of succeeding wheat crops. Foot-rot diseases seriously limited the value of the yield determinations in certain years after the third wheat crop of the experiment. When these diseases were absent, alfalfa produced favorable effects on yields of succeeding wheat crops. When the diseases were prevalent continuously cropped wheat plats produced the larger yields. An attempt was made to eliminate this factor in the evaluation of the protein data. All periods of alfalfa cropping, varying from 1 to 9 years, produced increases in protein content of wheat. Alfalfa cropping for as short a period as 2 years produced a favorable residual effect measurable by succeeding wheat crops over a period of at least 8 years. The longer periods of alfalfa cropping produced greater residual effects. Whether the maximum was reached less than 9 years of alfalfa cropping the data do not clearly reveal. It appears that residual effects may continue to be manifested longer in protein content than in yield. Diseases in the wheat in is experiment, however, have not permitted a clear verification of this statement.
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