U2 Commercial Gardening 



by means of stable manure and other vegetable and animal refuse) these 

 figures indicate that the subsoil really contains, on the whole, a larger 

 supply of plant food than the upper crust. Owing to the fact that the 

 latter is usually the only portion cropped it is not unnatural that it 

 should lose some of its available food and thus become poorer. Thus 

 one hears of a soil becoming "exhausted", by which is meant that it no 

 longer yields the same quantity of good saleable produce as formerly, 

 notwithstanding the fact that it has been cultivated and manured. The 

 " top spit", which is therefore usually regarded as the best soil, may be 

 really in a worse and poorer condition than the soil beneath it, owing 

 to constant cropping, and because it is "always carefully kept on top". 



If any reliance at all is to be placed on the figures quoted above from 

 Dr. Voelcker and others, it is palpable that there is an enormous supply 

 of plant food locked up in the earth, and if it can only be made avail- 

 able not all at once, which would be fatal, but gradually the culti- 

 vator has but to work his soil properly to liberate this food. 



But this is just where the chemical theorist fails and where the culti- 

 vator comes in. Jethro Tull and the author of the Lois Weedon System 

 of Cultivation were misled like many others with figures showing the 

 abundance of food contained in their soils, but in practice they failed 

 to obtain the best results. They practised deep cultivation, but they 

 overlooked the fact that something besides a good supply of mineral food 

 was also necessary. They overlooked the important factor of organic or 

 stable manure and humus generally. It is as true now as in the days 

 of Adam, notwithstanding our advance in the science of agricultural 

 chemistry, that the gardener or the farmer who would reap the best 

 results from his land must not only cultivate deeply, but he must also 

 " load his fallow ground with fattening dung". 



8. HOW TO EXTRACT PLANT FOODS FROM 



THE SOIL 



Assuming that the soil contains the food supplies already tabulated, 

 the only way to bring them within the reach of any crop is by a rational 

 system of supplying organic manures (see p. 145) and by deep cultiva- 

 tion. This is apparently a costly method, but it is really more economic 

 than the prevailing system, as we shall endeavour to prove. In these 

 days there is a good deal too much quackery about supplying foods to 

 plants in a chemical and more or less unnatural form. Growers are 

 told they have only to give their soil a dressing of this, that, or the other 

 special manure, and their crops will be increased a hundredfold. There 

 is never a suggestion of cultivating the soil deeply (that would sound 

 too laborious), and the natural condition of the soil itself is rarely taken 

 into account; whether it be clay, sand, loam, or gravel the same manures 

 are recommended in all cases and under all circumstances. The result 



