THE SUPPLEMENT TO THE 



Tropical Agriculturist and Magazine of the C. A. 8. 



Compiled and Edited by A. M. & J. FERGUSON. 



No. 2.] 



FEBRUARY, 1912. 



[Vol. X. 



THE ASSIMILATION OF NITROGEN 

 BY PLANTS. 



The Hawaii Agricultural Experimental Sta- 

 tion has contributed, through Bulletin No. 24 of 

 191], some valuable information bearing directly 

 on the manuring of paddy in respect of its nit- 

 rogenous requirements, but indirectly on the 

 fertilizing of all crops according to the condi- 

 tions of growth, e.g., whether on a dry soil or a 

 wet one. The prevailing idea with regard to 

 chemical nitrogenous fertilizers is that nitrates 

 are immediately available, whereas other forms, 

 including ammonium salts, are not. This idea 

 is supported by the fact that all nitrogenous 

 compounds in the soil tend to become converted 

 into nitrates. It does not, however, follow 

 from this that nitrates can be more easily trans- 

 formed into proteids. It is also not improbable 

 that the base of the nitrate and the acid radicle 

 of the ammonium salt may respectively exert a 

 stimulating or injurious effect. 



From the experiments of Pitsch, Muntz, 

 Griffiths, Hutchinson and Miller, it may be con- 

 cluded that some plants can utilize ammonium 

 nitrogen equally as well as, or better than, nit- 

 rate nitrogen. According to Kneller, rice devel. 

 oped better with ammonium salt in the early 

 stages.and with a nitrate during the later stages. 

 Nagaoka concluded that, in the case of irrigated 

 rice, the value of ammonium sulphate and a 

 nitrate stood in the ratio of 100 to 40— a con- 

 clusion which was corroborated by Daikuhara 

 and Imaseki. It is considered that the failure of 

 rice to properly assimilate nitrate may be due to a 

 lack of nitrate-reducing enzymes, which, having 

 long ceased to act through non-use, are no 

 longer developed in sufficient quantities to 

 enable the plant fully to satisfy its nitrogen 

 requirements; and is less likely to be caused by 

 an insufficient sugar content in the leaves. It 

 is well known that the result of denitrification 

 in water logged soils is the formation of nitrates 

 22 



which causes a loss of free nitrogen. These 

 observations go to signify that the nitrogenous 

 manuring of land must not be based solely on 

 chemical analysis, whether of plant or soil, but 

 also on the condition of the soil and the 

 character of the plant ; and that the selection 

 of a particular form of manure, whether nitrate 

 (and if so what nitrate), or an ammonium salt 

 (and if so which salt) or organic nitrogen in 

 some one of its many forms must be decided 

 after full consideration of the many factors 

 which govern the assianilation of the nitrogen 

 by the particular plant in question. 



LAND FOR COCONUTS. 



Soil Characteristics. 

 In an interview with Mr. F. W. Knocker, the 

 ' Penang Gazette ' got the following in reply 

 to a question as to what the conditions are 

 to be looked for, or points to bj observed, in 

 choosiDg land for growing coconuts. 



Chemical constituents and conditions to be 

 taken into consideration in choosing land for 

 coconut cultivation : 

 Name of Conditions 

 Chemical. under which it Mode of origin, 

 is found. 



Limes Seashore and Shells and lime- 



river beds. stones. 

 Phosphates Seashore. Fish and natural 



deposits. 



Potash Inland and Burnt bush, etc., 



seashore. & mineral alkalies. 



Nitrates do. Decayed and de- 



composed nitro- 

 genous vegetable 

 matter, & Datural 

 deposits. 



Sulphur Mountainous Pyrites, alluvial 

 districts. or»s, and volcanic 

 earths (washed 

 down by streams 

 and rivers). 



