G4S 



STATE BOARD OF AGRICULTURE. 



been taken just below the mulch it is probable that the freezing point 

 lowerings of the bare soils would have been somewhat higher. More- 

 over, the soluble salt content of the sands was not great. 



The effect of the growing crop is very local in this respect. Samples 

 were removed'at different distances from the growing phmts in the l»nre 

 soils in a number of cases. The results obtained as summarized in table 

 13 show clearly that the influence of the plants is not greatly felt be- 

 yond twelve inches, in some instances it extends over shorter distances. 

 Moreover, the presence of nitrates usually accounts for more than one- 

 half of the total solids as determined by the methods employed. 



The nitrate content of a number of surface samples was determined. 

 The samples were washed on a filter paper with distilled water until 

 the leachings were practically constant in concentration as determined 

 by the electrical bridge. The leachings were then evaporated to a small 

 volume, transferred to Kjeldahl flasks and distilled with potassium 

 hvdroxide and Devarda metal. The total ammonia found was calculated 

 toCa(N03)2. 



TABLE 14.— SOLUBLE SALTS IN SURFACE SOILS. 

 • Distance from Growing Crop. 



The( amounts of soluble material in several muck deposits have been 

 determined. We have repeatedly observed that salts accumulate on the 

 surface during periods of drouth or low precipitation. Recently our 

 attention was called to an unusual condition in a muck deposit near 

 Potterville. It was reported that onions were growing very slowly in 

 this particular soil although it was being cropped the first time. A visit 

 to the area revealed that aj)preciable quantities of salts had accumulated 

 on the surface, moreover the soil was moist. Samples were taken to 

 the depths shown in table 15 and also a sample of water from a drain- 

 age ditch. When the. first samples were taken the precipitation had been 

 negligible the previous thirty days. A few days after samiiling a two- 

 inch rain fell and the area was again visited and samples taken. At 

 this time the onions were growing with greater vigor than formerly. 

 The results of the determinations are given in table 15. 



