75 



hitherto been at all general. Mr. Bamber in 1893 indicated 

 several plants which might be useful for this purpose, and in his 

 book on the Pests and Blights of the Tea plant, Dr. Watt repeatedly 

 insists on the value of the method, and points out the plant which 

 has hitherto been most successfully employed, the Matt Kalai 

 (Phaseolus aconitifolius). 



A plant to be used as a green manure should fulfil the following 

 conditions : 



(1) It should be one which develops rapidly, so as to occupy 

 the land as short a time as possible. 



(2) It should give -the largest mass of green vegetation pos- 

 sible, for hoeing in. 



(3) It should be as deep rooting a plant as possible. 



(4) It ought to be sufficiently hardy to itself flourish under 

 fairly unfavourable conditions of climate and soil. 



(5) It ought, also, to return more to the land than it has 

 extracted for its own growth. 



(6) It should be grown at a time when it may retain manurial 

 constituents in the soil, which would otherwise be washed out. 



(7) It should easily rot when hoed into the land. 



(8) It ought to be grown without in any way interfering with 

 the tea or with the plucking of it. 



The conditions (i) (2) and (3) at once condemn the grasses for 

 green manuring. Neither rice, gra'ss, wheat, maize, nor buckwheat are 

 the most suitable plants for they all possess very shallow roots (see 

 Fig. Ill) and except for maize, the amount of vegetable matter to 

 be hoed in is small in proportion to the land covered by the crop. 

 Maize might, however, be valuable in some hill districts. In some 

 measure the same objection applies to a very large proportion of 

 the weeds of tea gardens. The Ageratum, known as cold weather 

 weed in Assam or " ilami" in the Dooars, and which forms perhaps 

 the most common weed in tea culture, though succulent in the 

 extreme, yet possesses a most meagre root development (see Fig. 

 IV) so that though usually a sign of well cultivated land it could 

 hardly be recommended for special planting as a green manure. 

 The same may be said of most other weeds which are not objection- 

 able in themselves. 



