46 Station Bulletin 372 



D. Subsoil Experiment at Northwood Ridge 



The results for the unfertilized plots showed a decrease in yield of corn 

 silage of 92.8 per cent when 100 per cent of the topsoil was removed and a 

 decrease of 60.4 per cent when 50 per cent of the topsoil was removed. 



Even where fertilizer was applied at the rate of 500 pounds of 5-10-10 

 per acre, the reductions in yield of corn were, respectively, 72.3 per cent and 

 49.8 per cent where 100 per cent and 50 per cent of the topsoil were removed. 



E. Miscellaneous Aspects 



During the course of the season, a noticeable difference in vigor appeared 

 among the potato plots at both Northwood Ridge and Strafford Ridge. Dur- 

 ing the relatively wet August, it was noted that the vines on the plots which 

 had recently received additions of organic matter were more resistant to early 

 blight infection. At both experimental sites, the plots kept continuously in 

 potatoes without organic additions were most heavily infected with early 

 blight lesions. 



L. T. Kardos 



The Influence of Soil Texture, Soil Moisture, and 

 Soil Aeration on the Growth of Plants 



Previous work showed that there was some benefit to cultures of to- 

 matoes, potatoes, and onions from additions of lignin and other wood-waste 

 products to the soil. Some emphasis has been made since then on residual 

 or long-term effects on the soil. 



Potatoes were grown in clay with three variables: (a) 800 ml. per plant 

 of lignin, (b) 800 ml. of peat, (c) soil only. All received an equal, liberal 

 amount of complete fertilizer. Harvest of tubers gave a moderate increase 

 in yield for both peat and lignin over controls. The soil from these cultures 

 was saved, remixed within each treatment, and returned to the containers. 

 A crop of tomatoes was then grown. Lignin proved markedly beneficial to 

 this second crop, but the low yield from peat is hard to explain. 



A sandy soil was used to raise a crop of potatoes with much the same 

 treatment as above. After harvest this soil was saved, remixed within each 

 treatment and to the lignin- and peat-treated soils respectively was added 

 enough of the organic matter to bring its volume up to one-third of the total 

 v/hen placed again in the original containers. The control was left untreated 

 and to each was added a liberal amount of fertilizer. These were allowed to 

 stand and compost for four months, being kept continually moist, before 

 planting tomatoes. The most striking result was the response of the controls. 

 Great difficulty was encountered in getting the plants to grow in this soil, and 

 even after new plants were transplanted again, several of them failed to sur- 

 vive. The average yields of those that survived were lower than those 

 treated with lignin or peat. Whether or not this effect was due to toxins, 

 micro-organisms, or other factors is open to conjecture. At least the organic 

 materials had some counteracting effect. A second crop of tomatoes is now 

 being grown in these soils. 



Shredded bark is another wood-waste by-products of interest. Some of 

 this was obtained and added to soil that had been previously sterilized by 

 steam. The soil was high in mineral nutrients. Tomatoes were planted in 



