Native grass behavior as affected by periodic clipping

1. Clipping native grass more than twice annually did not return enough additional production in the fifth year to pay for the labor. As the number of clippings increased, production declined. 2. The greatest yield of air-dry hay was obtained from the plat clipped twice and treated with barnyard manure 6 years previously at the rate of lo tons with 400 pounds of 20% phosphate per acre. 3. The least top weight was secured from plats clipped 8, 9, and 10 times annually. 4. The greatest root weight was obtained from the unmolested roadside grass and the next greatest root weight from an untreated plat clipped five times annually, from one plat clipped only twice annually but receiving an initial treatment of manure and phosphorus, and from one of the check plats. 5. The lowest production of roots by weight came from plats clipped most frequently and which also produced the least top weight. 6. The greatest root volume was obtained from the plats exhibiting greatest root weight. 7. The lowest root volume was found on the pastured area, on one of the check plats, on the manured plat, and on the plat clipped 10 times annually. 8. The roadside, check, and nitrated plats and one manured plat produced the highest root weight-volume factor. 9. Lower root weight-volume factors were obtained on those areas clipped more frequently. 10. Soil moisture was greatest on unclipped plats and larger in the various horizons on plats less frequently clipped. For the average of the 14 plats the 1 to 3 inch horizon contained the most soil moisture, the 12 to 15 inch horizon ranked second, and the 6 to 9 inch horizon third in the sixth year. 11. The lowest soil moisture in the upper horizon was found in the unclipped plats; in the second horizon, curiously, in one of the plats receiving manure and phosphate; and in the third horizon, in the most frequently clipped plats, as would be expected. 12. Soil organic matter was greatest in the upper horizons and in one of the plats receiving manure and phosphate, in one of the plats receiving NaNO3, and in one of the unclipped plats. 13. Low soil organic matter was not always found where expected and is apparently not associated with the amount of live roots. If soil organic matter content is quite permanently residual, it must be the result of previous vegetative growth. 14. The pH was highest in the upper horizon on plats manured and phosphated but clipped only twice annually. It was also high on unclipped, pastured, and roadside plats, but was highest in the lower (12 to 15 inch) horizon of plats clipped five times, one of which received manure and phosphate. An unclipped plat was also high. The lower horizon produced the highest average pH readings. 15. The lowest pH reading was found in the 6 to 9 inch soil horizon of a plat clipped nine times annually. Other low pH readings were distributed through the various horizons.