Mar. 2, 1920.] Agricultural Gazette of N S.W. 17T 



Soil Improvement for Maize* 



I. — Manures and Fertilisers. 



[Continued from page 116.] 



H. WENHOLZ, B.Sc. (Agr.), Inspector of Agriculture. 



Nitrogen from Fertilisers and from Leguminous Crops. 



The chief fertilisers supplying the element nitrogen are sulphate of ammonia. 

 (20 per cent.), nitrate of soda (15 per cent.), dried blood (13 per cent.) and 

 bonedust (4 per cent.); of these, nitrate of soda and sulphate of ammonia, 

 are water soluble, or can supply their nitrogen in a readily available form ;. 

 dried blood and bonedust are slower acting. 



From the tables on page 114 of last month's issue it will be seen (hat 

 a 50-bushel crop of maize i-emoves at least 50 lb. nitrogen per acre from the 

 soil, while the usual applications of nitrogenous fertilisers supply only 

 10 or 11 lb. of nitrogen per acre. These fertilisers can only then be 

 considered to have a stimulating effect, such as to increase the early root 

 development. Heavier applications are at present precluded on account of 

 the cost of these fertilisers — especially in the case of nitrate of soda and 

 .sulphate of ammonia. The latest prices of commercial fertilisers show that 

 every pound of nitrogen costs from lO^d. to Is., each pound of phosphoric 

 acid 2|d. to 3d., and each pound of potash about 4d. ; nitrogen is therefore 

 by far the most costly element to purchase in commercial fertilisers. As the 

 loss of this element is also the greatest in systems of continuous maize- 

 growing, it is apparent that the situation would be at once serious but for 

 the simple fact that the atmosphere consists of four-lifths of nitrogen, and 

 that leguminous plants (peas, beans, vetches, cowpeas, lucerne, clovers and 

 trefoils, &c.) have the power of extracting nitrogen from the air and of 

 utilising it by means of organisms which are contained in the nodules to be 

 seen on the roots of these plants. It is calculated that there is sufficient 

 nitrogen in the air above an acre of ground to produce lOO-bushel maize 

 cro[)S for 500,000 years ! In view of these facts, it is no wonder that atten.. 

 tion has been turned to obtaining nitrogen from this cheap source by means 

 of legumes, to provide for the loss of this element from the soil which heavy 

 crops of maize entail. The majority of farmers do not sufficiently realise the 

 imp rtance of legumes in this respect — though the value of ploughing in green 

 leguminous crops was known to the cultivators of the soil in the years B.C. 



Every farmer who has grown peas, vetches, cowpeas, or velvet beans, 

 (which only occupy the ground a comparatively short time), or lucerne and 

 red clover (perennial or biennial legumes), has observed the beneficial effect 

 on the following crops, even when the top growth is removed, as compared 

 with land where no legumes have been grown. Farmers should not, however,, 

 be deluded into the belief that such a system of growing legumes and such; 



