HOWARD AND HOWARD 99 
soil must be rich in organic matter to provide the nitrogen needed for rapid 
growth and also to preserve the soil texture during the late rains of August and 
September. After the last showers at the beginning of October, the soil between 
the rows must be deeply cultivated to supply the roots and nodules with abun- 
dant air. Thus organic matter, surface drainage and aeration are the chief 
soil factors which require attention. The importance of surface drainage 
needs no proof—in its absence in a wet season there is no crop. 
In the investigation of the effect of aeration and organic matter on sced 
production, a modified method of pot culture! was adopted. The pots 
consisted of pits, 3 feet square and 18 inches deep, filled with soil diluted with 
various aerating materials or mixed with various manures. The pits thus 
act as culture pots. If prepared before the rains, the soil settles down and 
by August are ready for sowing with indigo. In this way, many difficulties 
are avoided such as the water-supply and the effect of temperature. Peried- 
ical measurements of the height are made, determinations of the soil moisture 
and available nitrogen are carried out and after the seed is harvested, the 
weight of dry stem, less the leaves, is recorded. The results are set out in 
Table I. 
1 Agr. Jour. of India, Special Indian Science Congress Number, 1918, p. 36, 
