Feb. 2, 1920.] Agricultural Gazette of N.S.W. 115 



Where 80 or lOO-bushel maize crops are raised, as in some instances on the 

 alluvial soils on the coast, the depletion of the fertility elements obviously 

 goes on much faster, and the amount of plant food removed by such heavy 

 crops is by no means wholly replaced, even by the usual application of 

 fertilisers. It is, of course, largely the ready availability of the plant food 

 in such fertilisers which is responsible for the increased yields that result 

 from their use. There is no doubt that on some rich alluvial soils which are 

 given good cultivation, sufficient plant food material can be made readily 

 available without the addition of fertilisers for some years yet ; but it is a 

 matter of experience that it is much better economy, besides being much 

 easier, to maintain or increase the productivi;y of a fertile soil than to restore 

 fertility to an exhausted one. These facts, with the additional weight given 

 by the results of actual tests with fertilisers, no longer allow of the contention 

 that artificial fertilisers are not necessary for maize growing on most of 

 our soils. 



Every practical farmer knows that moisture in the soil is essential for 

 fertilisers to have effect on the crop — from first considerations and from the 

 actual experience of the very beneficial results obtained from most fertilisers 

 in wet seasons. This knowledge can be applied by having the soil well 

 provided with humus or decaying organic matter to hold the moisture. In 

 the decay of organic matter also carbonic acid is formed which renders much 

 plant food available from insoluble substances. It is a ruinous policy to 

 ap[)ly fertilisers alone to a soil which is lacking in humus and which dries out 

 quickly. 



All the experience with maize growing points to the fact that it is almost 

 impossible to make the land too rich for the crop. Record yields of over 

 200 bushels per acre have been made in America by the addition of 40 to 

 60 tons per acre of stable manure and 30 cwt. or so of chemical fertilisers. 

 Impracticable as this is, it is certain that it is waste of time, energy, land and 

 money to attempt to grow maize on poor land. A considerable growth of 

 stalk must take place for heavy grain yields, and it is only good land which 

 will enable this stalk development to take place. If it is desired to grow 

 maize on land which is not rich enough to permit a good growth of stalk, it 

 is best to build up the fertility of the soil with other crops before attempting 

 maize. How this can be done will be shown later. 



There is a common opinion that rotation of crop? will maintain the fertility 

 of the soil and render the purchase of commeicial fertilisers unnecessary. 

 There may be some truth in this for a few years at least on some of our new 

 soils, though it depends on the crops grown and the use to which they are 

 put ; but on old fields under the best rotation at Rothamsted and in America 

 it has been proved that the yields are reduced by half after many years 

 if fertilisers are not employed. 



Of the chief elements of fertility, phosphorus functions in the production 

 of seed while nitrogen and potash (particularly the latter) go more largely in 

 the production of stalk and leaf. From the figures given it will be seen that 

 three-fourths of the total phosphoric acid removed by the maize plant is 



