VEGETABLE GROWING^ IN NEW SOUTH WALES. 19 



(c) Nitrogen. Manures containing nitrogen are most required by crops 

 that make a large amount of leaf growth, like cabbages, lettuce, etc., which 

 are specially grown for their leaves, and in which quick growth and succu- 

 lence are desirable. On the other hand it is not usual to employ these 

 manures in connection with leguminous crops (peas, beans, &c.), as certain 

 bacteria in the soil associate themselves with the roots of these plants, and 

 enable them to make use of the nitrogen of the air in a way that other 

 plants cannot. The best-known nitrogenous fertilisers are sulphate of 

 ammonia, nitrate of soda, and dried blood. In the first two, the nitrogen is 

 present in a form that readily dissolves in water, so that it is quickly 

 available to the plant and produces rapid development of the crop. In dried 

 blood, however, and in farmyard manure, bones, meat, (fee., the nitrogen is 

 not in a state in which it can be immediately utilised by the plant, but 

 requires first to undergo some change while lying in the soil. Hence, dried 

 blood should be added to the soil some time before it will actually be required 

 by the plant, or in the case of a slow-growing crop it can be applied when 

 the seed is being sown. 



Sulphate of ammonia is the chemical fertiliser most used for its nitrogen 

 content in N"ew South Wales. In price it is cheaper than nitrate of soda, 

 and contains a larger proportion of nitrogen. Neither of these manures 

 should come in contact with the seed at sowing ; they are better applied to 

 vegetable crops as a top dressing, but on small areas like kitchen gardens 

 about 1 oz. or 2 oz. can be dissolved in water and applied through the 

 watering can. In such instances 1 oz. of the fertiliser per square yard would 

 be a substantial dressing at any one time. 



Generally speaking, however, nitrogen is supplied to vegetable crops in 

 stable manure of which liberal quantities should be regularly added to the 

 soil. Thf> importance of this matter is of sufficient significance to be the 

 subject of a separate section. 



Manures that chiefly Affect Soil Condition. 



In addition to the foregoing, which are chiefly used for the plant-food 

 that they supply direct to the plants, there are manures that are more 

 directly manures for the soil than for the plants. These are more related, 

 of course, to the fertility of the soil and have therefore an important relation 

 not so much to the immediate present as to the future. 



Organic Manures. 



The most effective means of supplying necessary plant-food to the soil and 

 generally of maintaining fertility, is the addition of vegetable matter either in 

 the form of stable or farmyard manure, or of compost manures. The processes 

 by which the plant food contained in such materials is made available to 

 growing plants, owe their efficiency in a large degree to th'e production of 

 humus from the decay of the vegetable matter. It will not be out of place 

 to discuss briefly, in the first instance, what are the functions of humus in 



