INSPECTION OF COMMERCIAL FERTILIZERS 51 



has been about Gl on the basis of ch-y matter yield and GO on the basis of nitrogen 

 recovery. The average availabiUty of the water insokible nitrogen has been 

 about Go on the basis of dry matter yield and G4 on the basis of nitrogen recovery, 

 as com]jared with Dried Blood at 80. 



Distillery Waste Fertilizer. This is the first experiment with tliis material, 

 which is not valued primarily for its content of nitrogen, but is a complete ferti- 

 lizer mixture composed of distillery waste jjroduct to which is added superphos- 

 phate, jiotash salt and anhydrous ammonia in amounts to furnish a 3-8-4 grade. 

 Practically all of the nitrogen present is in water soluble form; therefore, the 

 material is not listed in Series II. In dry matter yield and in nitrogen recovery 

 the fertilizer compared favorably with medium grade Tankage as a nitrogen 

 source. (See page 42, Control Bulletin No. 45, December, 1928, Massachusetts 

 Agricultural Exjjeriment Station.) These results do not .justify claims for supe- 

 riority of the fertilizer due to the presence of a relatively large amount of soluble 

 organic vegetable matter. The fertilizer to which manganese sulfate was added 

 seemed to have a depressing effect ujjon both the yield of dry matter and the 

 nitrogen recovery, — in other words, the manganese sulfate did not increase the 

 effectiveness of the fertilizer. 



Fleshings from Hides. This is the first experiment with this material. 

 About 63.5 per cent of the nitrogen was in water insoluble form and was found 

 to be of excellent quality. The nitrogen derived from the water insoluble por- 

 tion of the product had a much higher availability than that derived from the 

 original ground but unwashed material. This same characteristic has been 

 observed in case of other products under experiment, and might indicate that 

 the water insoluble portion contained some substance that was toxic to soil 

 organisms or possibly to growing plants; or that the washing treatment removed 

 some colloidal material, thus making the washed i:)roduct more easily attacked by 

 decomposition organisms in the soil and rendering the nitrogen more quickly 

 available. 



Garbage Tankage. One samjjle of this ]3roduct was included in the 1929 

 experiment and showed availability of about 47 on the unwashed and 42 on the 

 washed material, as compared with Dried Blood at 80. Information was secured 

 as to the manufacturing source of the three samples under experiment this year, 

 in order to check the uniformity of the product as offered to the trade. The 

 results secured are rather more favorable to the product than were expected, 

 judging from the previous experiment, and show a rather wide variation in effect- 

 iveness. The availability of the total nitrogen varied from about 53 to 59, and 

 the water insoluble nitrogen availability varied from 68 to 84, as compared 

 with Dried Blood at 80. The availability, particularly on the washed ]3ortion, 

 seems high for this class of materials, and it is hoped that further studies of these 

 products may be made in 1931. 



Linseed Meal. This is the first experiment with this product. The nitrogen 

 availability exceeded that of Dried Red Blood, classing the ])roduct as an excellent 

 source of nitrogen. 



Peruvian Guano. This completes three experiments on this product. All 

 three sami)les showed very satisfactory nitrogen availability. The alkaline 

 laboratory method, as has been previously pointed out, does not give a fair index 

 of nitrogen activity for this class of products. The so-called neutral method, 

 however, is quite satisfactory, giving results that indicate the superior quality 

 of the nitrogen. 



Rapeseed Meal. The nitrogen in this ])roduct was shown to be of good 

 quality, comparing favorably with the nitrogen from Cottonseed Meal. The 

 sample with the lowest nitrogen content, and therefore with the highest per- 



