26 



Effect op nitrogen. 



A grower may with considerable certainty determine by tbe 

 appearance of his trees the condition of his grove in respect 

 to the supply of nitrogen available in the soil. An abundance of 

 nitrogen is indicated by a dark green colour of the foliage, and 

 rank growth. The fruit shows the effect of an abundance of 

 nitrogen by being, in general, large, with a thick and com- 

 paratively rough rind. If the trees have a yellowish foliage, 

 with comparatively small leaves, and show little or no growth, 

 there is probably a lack of nitrogen. In this case there is 

 but little fruit formed, and that formed is small and usually 

 colours early. If the tree is starving from a lack of nitrogen, 

 the foliage will become very light yellow and sparse, and small 

 limbs will die, as will also the large limbs in extreme cases. If 

 the starvation is continued, no fertiliser being added, the tree 

 will finally die back, nearly to the ground, and j^i'obably die 

 entirely. The extreme symptons of general starvation from 

 lack of elements are probably nearly the same. The nitrogen 

 used in fertilisation is commonly derived from mineral or 

 organic sources. Of the former, sulphate of ammonia and nitrate 

 of soda are the forms most used ; of the latter, muck, dried 

 blood and bone, cotton seed meal, tankage, fish scrap, stable 

 manure, etc., are the forms most commonly employed. 



Injurious action of Muck. 



Muck is very commonly applied in considerable quantities 

 either in a raw state or composted with sulphate of potash, etc. 

 Many growers rather fanatically hold to what they term 

 natural fertilisation. By this is usually meant giving the tree 

 nourishment in the form in which they suppose it to be derived 

 in nature. It is contended by many that muck is principally 

 decaying vegetable matter, and that as this is the form of 

 nourishment which the trees obtain in nature, it must be a 

 good fertiliser to use in cultivation. But it must be borne in 

 mind that orange trees as we cultivate them are decidedly not 

 in a state of nature, except that by the cultivation of centuries 

 we have made cultivation and manuring natural conditions 

 which the plant demands. Trees in nature bear fruits for seed 

 to reproduce the species ; on the contrary we grow fruits for 

 market, and favour a seedless variety. We want a smooth, 

 thin-skinned, tender, juicy fruit that will sink in water. 

 IsTature does not pay particular attention to these characters, 

 so we watch for freaks and sports, abnormal plants, which have 

 the characters we desire, and when found we render these 

 characters permanent by budding. Our aim in cultivation is 

 not to produce the fruit we find in the wild state, but to modify 

 that fruit to suit our purpose. One of the most efficient 



