Agricultural Research in N. H. 45 



eggs ,and livability of chicks was equivalent to rations containing sulphite 

 yeast and meat scrap or soybean oil meal and meat scrap. Sulphite yeast ap- 

 pears to contain the "animal protein factor" necessary for hatchability of 

 eggs and growth of chicks. The riboflavin present in sulphite yeast is avail- 

 able to the hen and is satisfactory for meeting the needs for this vitamin for 

 the production of eggs with high hatchability. 



R. C. RiNGROSE 

 I J. Seiberlich, Engineering Experiment Station, co-operating) 



SOILS 



Methods for Controlling Erosion on 

 New Hampshire Potato Farms 



A. Rainfall and Runoff at Northwood Ridge, N. H. (Runoff plots 70' x 

 14' with 7 per cent slope) 



A total of 36.26 inches of rainfall occurred during 1946. This was ap- 

 proximately 2.8 inches below the normal amount at Durham which is 14 miles 

 away. The maximum water loss during any one runoff was 2.92 inches and 

 occurred as a result of a light rain upon a thawing 8-inch snow cover on 

 frozen soil. The annual soil losses on this Paxton fine sandy loam were 

 slight but the greatest loss occurred on a plot which has been in potatoes an- 

 nually since 1940 without a winter cover crop. 



B. Cropping and Soil Structure Data from Northtvood Ridge Runoff Plots 



The average potato yield on the winter rye plots was 7.9 per cent greater 

 than that of the non-green manured plots and 3.4 per cent greater than that 

 ot the clover hay rotation plots. In the latter case, the potato crop was the 

 second after plowing down an excellent clover-timothy sod. 



Sod cores taken in 1943 from the runoff plots were subjected to three 

 kinds of aggregate analyses: (1) gentle-dry sieving, (2) wet sieving of segre- 

 gated aggregates having an initial size range of 3 to 5 mm. diameter, (3) 

 wet sieving of a sub-sample having a wide range in initial aggregate and 

 particle sizes. 



The data obtained by using procedure 2 indicated that the aggregates 

 retained on the 0.3 mm. and the 0.2 mm. sieves were least stable and that 

 those retained on the 0.5 mm. sieve were most stable. Similar conclusions 

 were derived from a comparison of the data obtained by using procedures 1 

 and 3. 



Porosity values for the cores taken in 1943, 1944, and 1945 indicated 

 no significant differences because of the widely fluctuating amount of stones 

 greater than 4-mesh in diameter which was present. The percentage of these 

 stones ranged from 4 per cent to 29 per cent of the total weight of the core. 



C. Rotation Experiments at Strafford Ridge, N. H. 



Of the plots cropped annually to potatoes, the winter rye plot led by ap- 

 proximately 40 bushels. Of the two-year rotations, the crimson clover plots 

 outyielded the rye grass plots by approximately 35 bushels. Of the three- 

 year rotations, there was relatively little difference in the yield of potatoes 

 from the oats-clover hay and the oats-grass hay plots, with the clover rota- 

 tion having a very slightly greater yield. 



