October, 1909.] 



349 



Miscellaneous. 



next rains the trees send out side 

 branches aud produce irregular-shaped 

 trees which never develop a six feet 

 trunk suitable for two or three years' 

 economical tapping. 



It has been proved that the flow of 

 latex from a rubber tree is effected by 

 endosmotic pressure which practically 

 means the amount of water in the plant 

 roots. 



It is the practice to tap Rubber in the 

 early morning and evening, and to dis- 

 continue during the heat of mid-day and 

 early afternoon. 



Daring the heat of day much water is 

 evaporated by the leaves and latex flows 

 slowly, but in early morning and evening 

 water wishes to enter by the root 

 quicker than it is evaporated, with the 

 result that there is an internal pressure 

 which helps the flow of latex, therefore 

 it is practical to assume that there is 

 an intimate connection between the 

 presence of water in the surface soil 

 surrounding the roots, aud the flow of 

 latex from the Rubber tree. 



For half the year in Nyasaland there 

 is no rain, and daily the sun is strong 

 enough to evaporate water from the 

 plants and from the soil. The ques- 

 tion arises, where does this water come 

 from ? and the answer is from the lower 

 layers or subsoil by rising to the sur- 

 face in the form of water vapour and 

 water liquid (capillarity). 



In the surface soil of a clean weeded 

 estate the water daring day is princi- 

 pally in the form of water vapour, the 

 ' water being vaporised to a considerable 

 depth by the direct overhead rays of 

 the tropical sun. 



In the surface soil of an estate grow- 

 ing a green manure crop there is a 

 large portion of the water in the liquid 

 form, as the covering of vegetation re- 

 duces the temperature of the surface 

 soil and prevents the direct penetra- 

 tion of the sun's rays. Therefore, when 

 Rubber is growing surrounded with 

 vegetation, its roots have actual access 

 to liquid water through the greater 

 part of every day. 



If we examine the same soil during 

 the dry season after the green manure 

 crop is dead, we still find more mois- 

 ture in the latter, as the dead remains 

 of the green manure crop absorb and 

 retain water more firmly than ordinary 

 soil, but delivers it freely to the rubber 

 roots although not as freely to the 

 atmosphere. 



Plants for Green Manuring. 



Any plant belonging to the Natural 

 Order Leguminosce increases the nitro- 

 gen in the soil, but the amount of in- 



crease depends on the luxuriance of the 

 crop, and whether it is harvested or 

 turned into the soil. Any of the 

 following crops are suitable for this 

 purpose in Nyasaland :— Native Beans, 

 Earth Nuts, Soy Beans, Covvpeas, 

 Lucerne, Egyptian Clover, Crotolaria. 



With a green manure croo plenty of 

 seed should be used, and it" should be 

 turned under when the crop has reached 

 its maximum luxuriance which is usually 

 at the time of flowering:, a small portion 

 of the estate being left to produce seed 

 for the next season. The advantage of 

 turning under before ripening is that 

 the crop decomposes more rapidly as 

 the tissues always lignify (turn to wood) 

 after the flowering stage has been 

 reached. 



The most desirable characters in a 

 green manure crop is abundance of 

 balky nitrogenous vegetation contained 

 in soft aud easily decomposable tissues. 

 All the above crops except Crotolaria 

 are useful cattle foods, and some of them 

 are exportable, but, of course, if the 

 seed is exported the manuring benefit is 

 reduced. 



Crotolaria striata is the green manur- 

 ing plant most nighly favoured in 

 Ceylon and the Federated Malay States 

 for Rubber ; an experiment in Ceylon 

 showed that 14,000 lbs. of organic matter 

 per asre was produced and was estimated 

 equal to 700 lbs. of nitrate of soda. Ni- 

 trate of soda costs 10s. per 100 cwt. in 

 England, and, the seed costs 3^cf. per lb. 

 in Ceylon, 5 lbs, per acre being sown ; 

 there must be profit when we also consi- 

 der that the cost of weeding was re- 

 duced to a minimum. 



Egyptian Clover or Bersim (Trifolium 

 Alexadrinum).— This is the green manure 

 crop of Egypt, where it is grown twice 

 in a three-year rotation with Cotton. 



It is rightly held by most authorities 

 that the high yield of Cotton in the 

 Delta is the result of using this highly 

 valuable nitrogenous Clover as a rnanu- 

 rial basis for the cultivation of Cotton 

 crop. 



The amount of green forage per acre 

 produced is as much as 7 tons per cut- 

 ting, and frequently four cuttings are ob- 

 tained in six months, aud fed to cattle 

 on the land, the manure and urine 

 being returned to the soil, 



Earth-Nuts.— It is very questionable if 

 much benefit is obtaiced from this crop 

 when the nuts are gathered and export- 

 ed, but if the crop is turned in at 

 flowering stage, there are few better 

 crops for green manuring. 



It is not advisable to leave it till ripe as 

 the high percentage of oil in the seed 



