48 



Journal of the Department of Agriculture. 



Yields of wheat for the different systems of soil treatment are 

 given below : — 



Table II. 



The above yields are the averages of five plots in each case. 



After carrying oats and vetches the plots were all ploughed in 

 the spring', the green manure plots some four weeks before the others. 



It will be noticed that the system of returning the whole oats 

 and vetch crop to the soil has resulted in an average annual return 

 of wheat per acre of a little over three bags ; feeding off with sheep 

 not quite two and a half bags per acre ; and removing the crop as hay 

 a little over two bags. Greater differences may v)e expected between 

 systems B and C as time goes on, for although the system of cropping 

 outlined in C is better than that usually practised by grain farmers, 

 the farmer cannot hope to maintain the organic matter content nor 

 the nitrogen balance of his soil by this means only. 



The attention of grain farmers is drawn to system B of soil treat- 

 ment. A similar system by which one crop in a grain rotation is 

 grazed off by sheep could with advantage be adopted by many growers. 

 A large proportion of the plant food and a fair proportion of the 

 organic matter of the crop will be returned to the soil by this means. 

 The system has gained favour in many parts (f Australia, where 

 merino or cross-bred ewes with cross-bred lambs at foot are grazed on 

 crops such as oats or kale. 



The relative economy of these systems of soil treatment can only 

 be determined later when results have been obtained over a longer 

 period and the treatments have affected the soil in a definite way, in 

 spite of opposing influences which may be at work. > 



Manurial Experiments. 



These can be divided under three heads: — 



1. Liming experiments, of which there are three intended to test 

 the relative merits for soil improvement of caustic lime as against 

 ground limestone, and to decide the most economical dressings of 

 these forms of lime to apply. 



2. Trials with Saldanha Bay raw rock phosphate. 



3. General manurial experiment, which will later show amongst 

 other things — 



(a) Which is the best form of phosphate for this soil — super- 

 phosphate, basic slag, bone dust, or Cape Cross phosphate. 



