14 The Profitable Culture of Vegetables. 



texture part with their moisture too readily, and the crops on 

 them are therefore very liable to suffer from droughts in dry 

 weather. To overcome this objection measures must be taken 

 to make them more compact. The addition of powdered chalk 

 to sand or gravel, and particularly of humus to all three will 

 bring about the desired improvement. Humus can be added 

 either by heavy dressings of yard manure or by digging or 

 ploughing in at intervals quick-growing green crops. 



But it is on clay soils that the greatest alteration in texture 

 can be made. Such soils are tough and tenacious, and sticky 

 in wet weather; liable to crack badly and to set into hard 

 lumps when the weather is dry. They, however, possess 

 inherent fertility to a greater degree and are less easily ex- 

 hausted than light soils. They are capable of great permanent 

 improvement, and when drained and deeply worked only need 

 to be made friable to form one of the best soils for the growth 

 of vegetables and fruit. 



Lime. It has been said that clay soils are a storehouse of 

 plant food, the key to which is not always forth-coming, but, 

 providing the preparatory operations already indicated have 

 been duly performed, the addition of lime to clay soil will 

 unlock the storehouse. Under the influence of lime such soil 

 will become crumbly and friable and less retentive of water, 

 so that it lies drier and warmer and is fit for cultivation earlier 

 in the spring. 



Apart from its physical effect lime has also a great influence 

 in bringing inert plant foods into an available condition ; 

 on this subject more will be said in the chapter dealing with 

 manures. 



The method of liming formerly in vogue consisted in 

 applying large quantities at long intervals, five tons per acre 

 not being an unusual quantity, but recent investigation and 

 experiment has shown that lime is more effective if applied 

 in much smaller quantities at frequent intervals say 5 to 10 

 cwts. per acre once in three years and that calcium carbonate 

 (ground limestone rock or powdered chalk) is for most pur- 

 poses quite as effective, much cheaper, and easier to apply 

 than quick-lime. 



