1922.] The Ninth Indian Science Congress. LS.C. 29 
Availability of the Trichinopoly Phosphatic nodule as a 
manure for Paddy.—By M. R. RamAswam Sivan 
In the sense book of 1918 of the Madras Agricultural Department, a 
criptive account of the phosphatic nodules of Trichinopoly has been 
published in whieh the author pointed out that the mineral Secor 
too much of lime and also of iron and alumina to be economically man 
faetured athe part phate, atid that the best method of utilising it 
oo 23 grind it fine eae pply the seed gh rth ne al 
oe organic matter to paddy soils most of which, 
ont ere deficient i in phosphoric are as revealed bs the fe nin 
veys. A number of investigations were carried out for tne last 4 or 5 
years to Seteva te the actual penigy 7s? of this mineral phosphate 
under swampy paddy soil conditions. While the oe work is being 
written up, in det tail, for a later iecadeniental publication, some aspects 
of it are — now to the delegates of the A oeioutnitat section of the 
Science Congre 
These inv jaticntiens included the determination of-- 
(1) the solubility of the phosphate in carkoni ce 
(2) i ‘golubili ty in peepetat: scone of citric aci 
(3) its “availability as measured by evrectaat solubility in composts 
tle ma 
with green man 
(4) its availability as measured b sips growth ps paddy plants in 
(5) whether increased application of the: Phosphate gave increased 
ropping with and without green manure in pots, a and lastly 
(6) its eta labeliey as measured by the srk of paddy in field 
scale on ryot’s lands in conjunction with green manure. 
As regards its solubility in senntee acid and in citric acid, the greater 
the strength of the acid the more was the phosphate dissolved—a result 
in consonance with the coarvaiiin of previous work 
he amount of phosphate dissolved in ammonium citrate according 
si 6G 65°C was 
greatest in eek’s compost and became less a 
composts, anieting Sighs: et si were of the soluble aha sphate re- 
verting in the longer kept compost r the method of analysis requiring 
modification. Probably both the x ete are eegiahe - there is over 
17% of calcium oncboiinte n the mineral and as a later method, modifi 
y Dr. Harrison at , gave a soluble Shoapborls acid on 
skins at room seuberiiae — of at 65°C. 
4 
he next series of nape ments, t 
