500 



The Supplement to the Tropical Agriculturist 



The hoeing-in of green-manure acts bene- 

 ficially in many ways. , . . The essential con- 

 ditions necessary to be effective are plants that 

 will grow quickly so as to interfere as little as 

 possible with cultivation, that will give a large 

 crop of vegetable matter, and that will pene- 

 trate deeply into the subsoil. . . . The crops 

 that so far have given the best results are mati- 

 kalai (Phaseolus mungo), dhaincha (Sesbania 

 cannabina), arahar dhal (Cajanus indicus), and 

 Crotolaria striata. 



Dhaincha has come greatly into favour re- 

 cently and shares with mati-kalai honours for 

 first place: in the estimation of many planters 

 dhaincha is the more suitable plant as it grows 

 and gives a good crop on land where mati- 

 kalai proves a failure. One point in favour of 

 mati-kalai is that it is very rich in nitrogen. 



Beneficial results have been obtained by 

 growing arahar dhal on land from which old 

 bushes have been uprooted and replanted with 

 youg tea; the texture of the partially exhausted 

 soil has been greatly improved, and the burial 

 of organic matter and ready available plant-food 

 has given the young bushes their needed start. 



Crotolaria striata proved a failure as a green 

 manuring crop at Heeleaka, but good results 

 have in many cases been obtained by sowing in 

 June and hoeing-under in November. 



Wild leguminous plants are found in all tea 

 districts and in selecting any for green-manuring 

 preference should be given to those growing 

 luxuriantly in the neighbourhood. 



Bogga medeloa (Tephrosia candia) is now 

 grown very extensively on light soil and has 

 proved of great value; large quantities of suc- 

 culent shoots are cut from the plants and buried 

 at each round of hoeing. 



It is a perennial, but in seme districts the 



plants die when only two years old 



When the great improvement that can be 

 effected in the tilth and fertility of tea soils by 

 the addition of organic matter is taken into 

 consideration it is difficult to understand why 

 up-to-date planters go in for green-manuring on 

 so small a scale. 



Of course, there is the all-important question 

 of labour, but few estates are so short-handed 

 that they could not annually hoe organic matter 

 into, at least, one-sixth of their area under tea. 

 — Statesman, Nov. 1. Thea. 



USEFUL FACTS FOR THE TROPICS. 



There is always a suspicion of a Forest Officer 

 magnifying his office when he attempts to show 

 the great and beneficial influence of Forests on 

 Rainfall. Forty to fifty years ago, there was a 

 school that insisted that forests directly at- 

 tracted rain-clouds which would otherwise pass 

 over without precipitation ; and so warnings 

 were frequent as to the evil effects of the denu- 

 dation of forest anywhere in hill or low country. 

 Our reply was that the attraction lay in the 

 mountain ranges, and that a difference of 50 to 

 80 feet in the trees which grow on their sides 

 and summits could make little or no difference. 

 At the same time, we fully admitted the serious 

 risk which attended heavy falls of rain on cleared 

 land, tending to sudden floods and later on to 

 a want of the water supply which would have 



gradually, but surely, run down from forest- 

 covered land. Tneremedyto a considerable ex- 

 tent came when clearings got well covered with 

 coffee, tea and cacao-bushes, and still further 

 when tillage allowed the rainfall to penetrate 

 properly into the soil. Neverthless, there is much 

 to be said for the Colonial Office rule that no 

 more forest land should be alienated in Ceylon 

 from 5,000 ft. above sea-level upwards, more es- 

 pecially with reference to the conservation of 

 the actual rainfall in these regions. But that 

 does not affect the argument for utilising to some 

 extent the wide extent of cultivable land be 

 tween Dimbula and Haputale without at all cut- 

 ting down any forest ; for the anomaly of a first- 

 class railway running through some 15 miles of 

 waste land without producing any development 

 or deriving any traffic, cannot continue for 

 ever. It is all right so long as the Colony is 

 otherwise abundantly prosperous and there is 

 no difficulty in making both ends meet. Should 

 that difficulty ever arise, waste land suited to 

 profitable cultivation will not be allowed to 

 remain idle even in the higher regions along 

 the Railway. But this is all aside from the 

 matter we wish to put before our readers 

 today. It is to draw attention to a new and 

 striking view of " the effect of forests on rain- 

 fall," which we find described in the Indian 

 Forester for the present month. It is based on 

 investigations made by French scientists which 

 demonstrate that in an average forest the area 

 of the leaves is at least ten times the area of 

 the ground which supports the forest. It is 

 further asserted that as all rainfall is directly 

 dependent on evaporation for its supply, and 

 as the amount of water evaporated from a given 

 area of leaf surface is sixty times the quantity eva- 

 porated from a free surface of water,— it follows 

 that the amount of moisture given off, under 

 similar conditions, from an acre of forest is 600 

 times the amount evaporated from a free sur- 

 face of water of the same area. The proportion 

 of land to water on the world's surface is as 1 to 

 3 and l-4th of the land area is supposed to be 

 under forest and then it follows that from l-16th 

 of the globe's surface under forest, 50 times as 

 much water is evaporated as from the water sur- 

 face of the world! From this it is scientific- 

 ally inferred that the rainfall of the world is 

 chiefly dependent on its forests, and, therefore, 

 of course, a new and vastly increased importance 

 is given to the work of afforestation, more espe- 

 cially in countries (like India) which are liable 

 to famines duo to failure of rainfall — although it 

 has yet to be shown that the ways of the Mon- 

 soons correspond with the attraction offered by 

 forest-covered tracts of country. 



NIGERIAN REPORT ON MALAYA, 



(Colonial Office Journal October.) 

 On the subject of the cost of plantations, an 

 interesting report by Mr N C McLeod, Deputy 

 Conservator of Forests in Southern Nigeria, 

 based on a visit made to the Federated Malay 

 States, has been laid before the Legislative 

 Council of Southern Nigeria. Mr McLeod states 

 that rubber is being grown in the Federated 

 Malay States on landpreviously under some other 

 crap err in fresh clearings. In the former case 



