Sas HOWARD AND HOWARD Lg 
black soils of the Central Provinces suffers from wilt and hardly yields any 
seed. Thus the deep-rooted varieties of patwa and sann behave exactly like 
the deep-rooted varieties of Java indigo and are severely attacked by wilt in 
the late rains. Roselle and the shallow rooted types of paiwa and sann on the 
other hand escape wilt. 
The general experience of 1919 affords considerable support to our views 
on the cause of wilt in indigo. For several years past, the rainfall has been 
heavy and floods have been the rule. Indigo has not done well and wilt has 
been common. The year 1919, however, was a year of short rainfall combined 
with the absence of floods. In consequence, the rise of the subsoil water was 
not considerable. The soil aeration was, therefore, above the average. Slight 
wilt occurred on two occasions only but the plant rapidly recovered. Three 
cuts of indigo were obtained at Pusa and the old plant is now exceedingly 
healthy after the rains. Many of the Bihar estates, particularly those which are 
most liable to waterlogging, did remarkably well in 1919, and for the first time 
for many years have reaped an excellent second cut. Although the area under 
indigo in Bihar in 1919 was 14 per cent less than in 1918, the outturn is expected 
to be greater than in 1918. Such a result would not be possible if the Bihar 
soils are suffering from depletion of one of the essential constituents of the soil 
solution. 
Indigo wilt is not met with during the rains in India on porous soils where 
the aeration is efficient. This interesting fact has been studied in two cases— 
at Dehra Dun in the submontane zone and at Chandkhuri in the Chattisgarh 
Division of the Central Provinces. At Dehra Dun, the monsoon rainfall is very 
high, often more than 100 inches. At the Harbanswala Tea Estate, where Java 
indigo was grown for some years, there is excellent surface drainage and the soil 
is remarkably porous, so permeable in fact that it is possible to walk over the 
fields a few hours after five inches of rain have been received. Here Java 
indigo grows with great rapidity, the plants are at least ten feet high and 
no signs of wilt can be detected. At Chandkhuri near Raipur in the Central 
Provinces, the results were similar. Grown on the porous laterite soils (bhata) 
under a maximum rainfall of over 60 inches, Java indigo thrives remarkably 
and no trace of wilt is to be seen!. Good crops of seed are produced although 
the soil is particularly poor in total and available phosphoric acid. When 
grown on the stiff and poorly aerated but richer black soils under similar rain- 
fall and similar climatic conditions, Java indigo develops much more slowly, 
(Plate V). 
1 Clouston, D. and Padmanabha Aiyar, A.R., Agr. Jour. of India, Special Indian Science 
Congress Number, 1918, p. 89. 
