110 SCIENTIFIC REPORTS OF THE AGRICULTURAL RESEARCH 



on nitrification was shown by the results obtained when 

 straw was added with the dung or urine. The losses of ni- 

 trogen that take place during storage are being further in- 

 vestigated. 



Observations of the effect of these manures on the crop 

 yield of oats in pot culture showed the growth of the plant 

 to correspond to the amount of nitrate formed in the nitri- 

 fication tests, but where a bad physical condition was pro- 

 duced in the soil, the yield was smaller than that expected 

 from consideration of the nitrate figures. 



Oats were grown in both pots and plots to which roots, 

 stems, and leaves or the whole plant of dhaincha (Sesbania 

 aculeata) and cowpea were added. The crops obtained 

 corresponded to the nitrate formation obtained in the 

 laboratory nitrification tests with these plants and their 

 parts. - 



Study of the wide variations in the accumulation of 

 nitrate during the decomposition of various oil-cakes in 

 Pusa soil tend to the conclusion that they are due to the 

 differences in the relative proportions of carbohydrate and 

 nitrogen in the cakes. The oil content had very slight in- 

 fluence on nitrification and the addition of such materials 

 as cellulose, filter paper, sawdust, starch, cane sugar and 

 glucose to cakes rich in nitrogen, retarded the accumula- 

 tion of nitrate. Further, in the case of mdhua (Bassia 

 lati folia) cake, no nitrate was found after eight weeks' in- 

 cubation, except when the cake had previously been 

 fermented. 



The nitrogen content of soil under fallow and growing 

 crops was studied. Both nitrate and organic nitrogen 

 •contents of the cropped plots were lower than those of 

 fallow plots and the differences were greatest during the 

 period of most active growth of the crop. 



Biological analysis of soils. Biological analysis of 

 soil from an abandoned coffee estate in Mysore was car- 

 ried out. 



Nitrogen fixation. Experiments on the effect of the 

 .accumulated products of its metabolism on the nitrogen- 



