558 Report of the Department of Horticulture of the 



Sod affects deleteriously the beneficial micro-organisms in an orchard 

 soil. — This is another statement which we cannot support with 

 experimental evidence. We are assuming than an abundant humus 

 content, good ventilation, comparatively high temperature, a more 

 uniform supply of moisture, more nitrogen from the cover-crop 

 turned under, all present and cooperating better in a tilled than 

 a sodded soil, give the best environmental conditions for these 

 bacteria. If the assumption is unwarranted, our agricultural teach- 

 ing of the day is radically at fault. In the light of what we know 

 about soil bacteria, little though it be, it is not unreasonable to 

 suggest that the micro-organisms in tilled land are more helpful 

 to apple-trees than in sod-covered land. 



Sod may " poison " the apple-trees. — The fact is well established 

 that all plants have a marked effect on soils. Just how plants 

 affect soils is not so clear. Certain it is, in the case of a sod of 

 whatever plant, much organic matter quite different from that 

 present before the sod, is added. It is not in the least strange, 

 rather it is to be expected, that this mass of new matter will change 

 the chemical and bacteriological properties of a soil, for good or 

 evil for other crops. There is, too, as everyone informed on recent 

 agricultural experimentation knows, considerable evidence to show 

 that plants, grass for instance, may excrete compounds toxic to 

 other plants. Is it not possible that sod may, then, set going some 

 action in a soil detrimental to apples? Literally, may not sod 

 poison the apple? 



Pickering 1 , at the Woburn Experimental Farm, Ridgemont, 

 England, has been experimenting with apple trees in sod and under 

 tillage since 1894, twenty years. The methods employed in the 

 New York experimental work, both in treatment of plats and in 

 gaging results are very similar and the results obtained are for all 

 practical purposes the same. A good summary of the conclusions 

 at Woburn as to causes is found in the following quotation 2 : 



" Direct experiments seem to negative the possibility of explaining 

 the action of grass on apple trees in the various ways which 

 we have discussed above, and lead us to a conclusion, which has 



1 All who are interested from the experimental standpoint in this work should 

 read Pickering's accounts of his work in the First, Second, Third and Fifth Reports 

 of the Woburn Experimental Farm. 



2 Third Report of the Woburn Experimental Fruit Farm, 1903: 47. 



