Mar. 2, 1920. J 



Agricultural Gazette of X.S.W 



1 83 



It is apparently a fact that it is in any case unwise to apply rock phosphate 

 to soil which is lacking in organic matter, but Truog* has put forward an 

 interesting theory that the solubility of phosphates is not the only factor that 

 <letermines the growth of the plant on different phosphates. He states 

 that plants containing a relatively high lime content have a relatively high 

 feeding power for raw rock phosphate, and that for plants containing a 

 relatively low lime content the converse of this is true. A lime content of 

 less than 1 per cent, may be considered relatively low. In this class are 

 millet, wheat, oats, rye, maize, barley (ranging from 0-46 per cent, to 0-90 

 per cent.). A lime content of over 1 per cent, may be considered relatively 

 liigh. This class includes rape, peas, lucerne, lupines, buckwheat, tobacco, 

 "turnips (ranging from 1-78 per cent, to 3-83 per cent.). As would be expected 

 irom the above, experiments carried out in New South Wales with wheat and 

 maize to compare the immediate effects of superphosphate and rock phosphate 

 on yield have shown decidedly in favour of superphosphate. The residual 

 effect of rock phosphate has not, however, been tested; and if it can be 

 •obtained at a reasonable price in Australia or from the island deposits in close 

 proximity to Australia, its value in this respect (for the question of permanent 

 fertility must be considered) and for the plants of high lime content mentioned 

 above is at least worth testing. 



Following are the results of experiments carried out with maize in New 

 South Wales with rock phosphate (Wellington) in comparison with super- 

 phosphate : — 



(To be continued.) 



The "Leaf-cutting" Bek. 



Reporting on a species of fly, said to be eating tops of Acacia pycnantha 

 in the neighbourhood of Narrabri, the Government Entomologist wrote : — 



The insect is a native bee belonging to the genus Megachile; it is known 

 as the " leaf-cutting bee " because it cuts off bits of leaves and carries them 

 into the cavity where it constructs its nest, and wherein it makes them into 

 oval cells. This bee often attacks rose bushes in gardens. The damage it 

 does is not likely to be serious to the trees it visits. 



* Wisconsin Univ. Agr. Expt. Sta. Research Bull. 41 (1916). 



