THE PRODUCTION OP WHEAT 25 



Manuring cereals then ceased, until it was found that 

 the warmer and drier summers experienced here allow 

 of the nitrification of the waste organic matters in the 

 soil to such an extent as to provide a sufficient supply 

 of nitrates for satisfactory plant growth. 



In the search for the element necessary for plants 

 and least plentiful in the soil, phosphorus was some 

 ten years ago found to be of great advantage, and phos- 

 phates are now being used to an increasing extent 

 to counterbalance the exhaustion of the soil due to 

 cropping. 



(2) Indirect. The indirect method is of special 

 importance to New Zealand conditions ; for the Dominion 

 is very well adapted to mixed farming. Two ways of 

 employing this method may be used, by a system of crop 

 rotation or by the grazing of animals on wheat lands. 

 In practice they are employed together when opportunity 

 offers. There are various systems of crop rotation, but 

 it will suffice to describe one and point out its advantages. 

 A rotation may begin with a root crop, usually turnips, 

 manured with phosphates. This crop not only gives an 

 opportunity for cleaning the land but it provides 

 excellent winter feed when supplemented by hay or, 

 more commonly, wheat straw. The residue left then 

 provides an excellent manure. After the turnips are 

 eaten off the farmer prepares the soil for a crop of 

 barley or oats, as it is now too late to sow wheat. The 

 land is ploughed, but the ploughing is 'only a shallow 

 one, so that the water stored in the deeper layers of the 

 soil which have been solidified by the trampling of the 

 sheep may not be disturbed. Clover and grasses are 

 sown among the barley or oats so that they may take 

 firm root whilst the latter is growing and ripening. The 

 crop is harvested in the autumn, and the young clover 

 and grasses establish themselves during the autumn or 

 winter, and produce a crop of hay the following year. 

 This is harvested in midsummer, and the aftermath 

 forms an excellent autumn grazing for the sheep and 

 cattle which are to be fed the next winter. 



In the autumn the ground is ploughed again, and 



