34 MASS. EXPERIMENT STATION BULLETIN 380 



healthy in proportion as the pastures are kept tolerably near to the plough — 

 are not, in short, of too great age in sward. ii^ 



John Orr, another prominent British authority on grass farming, writes: 



Nothing will establish British agriculture on such a sound basis as the 

 use of the plough for the growth of grass. . . . For the quick and eflfective 

 introduction into the soil of raw materials from which grass is made, and 

 for its speed}' production in finished form, the plough is necessary. i^o 



Such expressions of expert opinion concerning the best grasslands of England, 

 for years regarded as models of perfection in grassland management, are certainly 

 interesting if not revolutionary. If permanent pastures do not represent the best 

 pastures of England where soil and climatic conditions are generally favorable 

 for their best development, then prospects are indeed poor for making first-rate 

 permanent pastures out of the large area of run-down pasture land in Massachu- 

 setts, where both soil and climate are far less congenial. 



The Case jor Tillage in Pasture Culture. — Why is tillage essential to high 

 productivity levels in grasslands? If both historical evidence and present-day 

 expert opinion agree that the periodic plowing and reseeding of grasslands are 

 prerequisite to high productivity levels, then there must be some good funda- 

 mental explanation. In recent 3'ears experimental work has been carried out in 

 various parts of the world which has supplied some scientific evidence to support 

 early observations. Although still more scientific evidence may be necessary 

 to provide a full explanation, the following discussion in the light of present in- 

 formation supplies a plausible if not a totally correct interpretation. 



It was early observed in Massachusetts that adequate soil tillage for cultivated 

 crops was directly associated with soil moisture relationships. "The very Dews 

 will enter his pulverized Fields, with a larger Blessing than a large Shower can 

 give his Slovenly Neighbour because his ground is not fit to re».eive it or Retain 

 it," '21 wrote one Nathan Bowen, in 176L Later it was observed that moisture 

 relationships in grasslands become steadily poorer as the character of the sod 

 itself depreciates. The surface becomes hard and rather impervious to rainfall, 

 the water-holding capacity is reduced, and even the moisture already present in 

 the soil appears to be lost from the surface more readily by evaporation. 122 To 

 substantiate some of these observations, experiments reported recently from 

 New Jerseyi23 showed that the water loss, as total run-ofT, from a continuously 

 grazed pasture plot was four times as great as that from a grass-legume seeding 

 and even greater than that from the corn plot. Recent work on the evaporation 

 of water from bare soil surfaces, carried on at the Missouri Station, 124 indicates 

 that, for some soil types at least, moisture from below the surface may be con- 

 tinually lost through evaporation until the available moisture supply is depleted 

 to a considerable depth. It appears, therefore, that, as a sod becomes older, 

 particularly on sandy soils, certain physical relationships of the soil become pro- 

 gressively less and less favorable to plant growth. 



In order to determine just what factors were responsible for reduced yields 

 from aging sods, experiments were carried out in Germany on soils similar to 

 those in Massachusetts. In one series of experiments'^s certain physical prop- 

 erties of the soil were measured in natural meadowland and similar areas which 

 had been plowed and reseeded. It was found that in the plowed land the water- 



119piough-Up Policy and Ley Farming, p. 21. 



I20Scottish Journal of Agriculture, XX (1937), 3-40. 



12lField Husbandry, p. 208. 



122Mass. State Bd. Agric. 58th Annual Report (1910). p. 12. 



123Soil Conservation, V (1940), 256-258. 



124pfjya(g Communication from C. M. Woodruff, Dept. of Soils, Mo. Agric. Expt. Sta., 1941. 



l^^Zeitschrift fiiV Pflanzenernahrung Dungung und Bodenkunde, A XXXII (1933), 278-301. 



