xxxvi. Timehri. 



trees of our forests among weeds. Leguminous trees are of very common 

 occurrence in our forests and any one who traverses any of the small 

 creeks which meander through them may notice the enormous number 

 of root tubercles or nodules present on the rootlets of vast forest trees 

 which have fallen on the banks of the streams. Similarly on aban- 

 doned lands and especially on lands resting from sugar-cane cultivation 

 legumes are prominent among the weed-flora. Nature ever kind but 

 apt to be too profuse in her kindnesses to this colony ensures the con- 

 servation of fertility on our abandoned or neglected fields. Cultivators, 

 however, should take advantage of this by cutting down the weeds, 

 allowing them to wilt and then forking them into the soil. 



These three methods of countervailing to some extent the scarcity 

 of nitrogenous manure have each the merit of ameliorating the composi- 

 tion and textures of the soil and thus their effects are not limited to one 

 crop whilst in the cases of application of rice-straw and of that of 

 leguminous cover-crops the good effects are cumulative in their action. 

 Personally I look upon the utilisation of the rice-straw as a practical step 

 which ought to receive the attention of the more enterprising among the 

 planters. 



I noticed a few days ago in a local newspaper allusion to the scarcity 

 of potash for manuriai purposes. Fortunately our sugar and rice lands 

 are very rich in potash while cultivation sets free from such soils potash 

 in quanity far in the excess of the requirements of any tropical crops. 

 For instance the top-most acre-foot of the heavy clay soils of the Botanic 

 Gardens contains not less than 80 tons of potash, equal to 160 tons of 

 commercial sulphate of potash, per acre. 18 tons of this is soluble in hot 

 strong hydrochloric acid, one ton being dissolved by slightly acid water ; 

 f of a ton is in what is usually regarded as the condition in which it is 

 immediately available for plants and of this, potash, equal to 7 cwt. of 

 sulphate of potash per acre, is soluble in pure water. There is not any 

 likelihood of manuriai dressings of sulphate of potash having any effect 

 on such soils, nor of their requiring them for many years to come. 



This condition extends a long distance from the coast on the river 

 alluvial soils but is non-existent on the soils of the interior which are as 

 a rule abnormally deficient in potash. The We6t Indian sugar islands 

 may sutler from shortage of mauurial potash salts but some recent 

 geological analyses I have made for the Commissioner of Agriculture for 

 the West Indies indicate that the potash-containing mineral " alunite " 

 exists in certain of the volcanic islands. 



Humus. 



A question which has received much attention at intervals since 

 1897 is that of the importance of the organic constituents of soils 

 frequently but incorrectly lumped together under the head " humus." 



