COCONUT PLANTER'S MANUAL. 97 



cultivate tiie whole soil, or large circles round tlie palms, burning all refuse, 

 dead leaves, etc., and spreading the ash over the loosened soil. A few 

 months later, when the palms have begun to form fresh rootlets, manure 

 should be applied in six-inch deep trenches at 3 to 6 feet from the stems 

 and forked in with any decaying weeds, cheddy or available organic matter, 

 and the trench filled with soil. 



All coconut husks and newly-fallen leaves should be laid over this forked 

 area to retain moisture round the manure and so encourage root growth into it. 



On most estates the amount of organic matter available for mulching 

 purposes is comparatively small, and humus can only be added in quantity by 

 growing a green manure. For this pui'pose there are several suitable plant? 

 including two or three varieties of Tephrosia and Crotalaria. The Tephrosias 

 commonly found in the low-country and grown on several estates are 

 Tephrosia purpurea (Pila) with straight and narrow pods, and another variety 

 with curved hairy pods, also a creeping variety which is to be found in the 

 North-Central Province. Either of these grow freely, forming small bushy 

 plants about 18 in. high, the leaves being very rich in nitrogen containing 

 about 2'5 per cent on the dry material. As a rule the seed can be collected 

 with very little trouble and expense. An important variety is Tephrosia 

 Candida, which is larger and more robust, giving as much as 40 to 50 tons 

 of green material annually for 3 or 4 years. It grows well on rubber and 

 tea estates, and is now being tried on the sandy and cabooky soils of coco- 

 nut estates. Crotalaria striata and incaaa, also Cajanus indicus or the 

 Pigeon-pea are also very useful, the latter supplying a certain amount of 

 fodder for cattle and an edible grain. 



Such green manures should be sown in from 2 to 5 feet wide rowa 

 between the palms, and when 4 to 5 feet high, the plants should be cut 

 across at 15 in. and the material mulched over the forked ring where the 

 manure is to be applied and dug in with the manure. The leguminous 

 green manures average "86 per cent, of nitrogen on the fresh plant, a ton 

 containing 19J lb. of nitrogen. Many tons can be grown per acre. 



A well-grown green manure should supply far more nitrogen than 

 the palms require annually ; but while growing they absorb a large 

 amount of mineral matter, especially lime, potash and phosphoric acid, from 

 the soil and therefore are competing with the palms. This is given back 

 when the green material decays and reverts to humus, but it is advisable 

 to apply additional phosphoric acid and potash when a green manure is 

 being grown. They should also be cut across early in the dry season and 

 the material mulched to prevent too much moisture being absorbed or eva- 

 porated from the soil. 



The effect of green manures is permanently to improve the soil conditions 

 for bacterial growth, and to enhance the effect of artifical manures by in, 



a 



