The effect of sweet clover‐green manure and stable manure on the yields of grain and row crops have been studied since 1936. The treatments include the application of these manures every 2, 4, and 6 years. Sweet clover‐green manure had a more beneficial effect on the yield of crops than did stable manure. The greatest effects of both manures on crop yields occurred where the manures were applied every 2 years. In the 4‐ and 6‐year treatments, marked beneficial effects were noted immediately following, or 1 year after the application of the manures, with much less or no benefit occurring thereafter until reapplication. The effects of these treatments on the physical condition of the soil have been studied for 2 years. Granulation of the soil was enhanced by the 2‐year treatments. The effects of the treatments on the soil physical condition cannot be completely evaluated until a 6‐year study is completed.

Synopsis The weight of young corn plants in soil cultures in the greenhouse was found to increase with the content of phosphorus present naturally in the seed independently of seed weight. In field experiments, supplementation of the natural phosphorus content of each seed with 6 mg. of P as NaH2PO4·H2O applied in a glue coating resulted in an average corn yield 4.5 bu. per acre above that produced from seed treated with glue alone.