454 



JovrnoJ of A(/rici//t are, Victoria. [10 Aug., 1916. 



of a ton of lime (Plot 9) increased the yeld of hay by only a half 

 hundredweight. 



Even the addition of an extra ton of lime (Plot 2) gave only 8 cwt. 

 extra of hay over Plot 9, an increase which would not cover the cost 

 of the additional manure. Moreover, of all the phosphatic manures it 

 will be noted that super is the most effective. 



3. Nitrogenous Manures. — One of the most striking features of the 

 table is the effect of the nitrogenous manures on the hay yield. 

 Lucerne belongs to the family of leguminosae, all the members of which 

 are capable of extracting the nitrogen of the air. So far as is known, 

 this power of utilizing the nitrogen of the air is exclusively possessed 

 by this class of plants. For this reason peas, beans, clover, lucerne, and 

 other such plants are used as much as possible in building up a rotation 

 which will conserve the fertility of the soil. 



The curious wart-like nodules found on the roots of healthy lucerne, 

 peas, beans, vetches, and clover ,plants are really colonies of bacteria 



Fig. 3. — View of Lime Spreader Applying Lime to Land prior to Sowing 



Down with Lucerne. 



engaged in the work of assimilating free nitrogen from the soil air, and 

 transforming it into forms suitable for absorption by the plants. It 

 is usually considered unnecessary to add nitrogenous manures to 

 leguminous crops, even though the soil be naturally poor in nitrogen. 

 If nitrogenous manures are applied to these crops they will make use 

 of it, and correspondingly less nitrogen will be absorbed by the bacteria. 



The question that concerns the farmer is whether the application 

 of nitrogenous manures is a profitable practice. Whatever may be 

 said of the policy of using nitrogenous manures on lucerne, the results 

 at Werribee suggest that the practice is ,profitable. 



Compare, e.g.. Plot 4 with Plot 9. Both plots have a uniform 

 dressing of lime and super, but Plot 4 has, in addition, a dressing of 

 1 cwt. of nitrate of soda. The increase in yield due to this dressing is 

 19^ cwt., an increase worth 48s. 9d. per acre, and obtained by expending 

 an additional 15s. in nitrate of soda. 



