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Both the nature of the soil and the requirement of the crop has 

 to be considered in applying fertilizers. 



Nitrogen is essential to the production of a good leaf growth. 

 Phosphates are essential to seed production. Potash is necessary in 

 the production of woody growth and in the elaboration of carbo- 

 hydrates (sugar, starch, etc.,) and since it is believed that the caoutchouc 

 substance is built up from carbohydrate material, the application of 

 Potash should be beneficial. Lime is the essential constituent of the 

 wood, but is of more value indirectly in rendering available other 

 dormant plant foods in the soil. 



In the Federated Malay States, the soils are usually rich in 

 Nitrogen, although this constituent may not be in a readily available 

 form — owing to the sourness of many of the soils when first brought 

 into cultivation from virgin jungle, this being especially so in the 

 lowlying coast districts. 



Lime, Potash and Phosphate are generally very deficient. In spite 

 of the richness of the soil of many rubber estates, there are marked 

 exceptions where the soil may be described as very poor and where 

 the growth of the trees is very slow. 



Method of Application. 



Fertilizers should not merely be spread on the surface of the soil, 

 which on most estates is hard, as with a heavy rainfall they would 

 be rapidly washed into the drains. On all estates where the trees are 

 two years old or more, it will be found more economical and effective 

 to broadcast the manures and lightly fork over the surface soil. 

 Artificial fertilizers are best applied after mixing with fine earth — to 

 ensure better distribution. 



Fertilizers applicable to Certain Soils. 



Another important point in connection with the application of 

 manures is that certain manures must not be used on certain soils, 

 thus, Superphosphates as a source of Phosphoric acid and Ammonium 

 Sulphate as a source of Nitrogen should not be used on peaty soils, 

 as they increase the acidity of such soils. Superphosphates should 

 not be used on clay soils, and Sodium or Potassium nitrate should not 

 be used on clay soils as it deflocculates the clay, and renders it more 

 heavy. 



Organic nitrogenous manures, as a source of nitrogen. Potash 

 fertilizers and lime are specially suitable on light sandy soils. 



The application of lime to improve the physical texture and Bacis 

 slag as a source of phosphates is especially applicable to clay soils 

 which usually contain potash in excess. 



