204 Agricnlhirol GazeHe of N S.IF. [Mar. 2, 1908. 



purpose, and the selection will be guided by considerations such as the time 

 of year at which it is to be grown, its suitability to soil and district, &c. 

 Amongst the most effective class of crops for the purpose are leguminous 

 plants, such as clover, cowpea, lupines, &c., since these are specially v;iluable 

 on account of their power of obtaining their nitrogen from the air. They 

 are, therefore, especially suitabh; for soils poor in nitrogen, and are of high 

 value in enriching the soil with this ingredient. There ai'c. however, many 

 other crops which are suitable for the purpost;, and frequently used, such 

 as mustard, buckwheat, &c. These are all rapid growers, and can be grown 

 as catch-crops — that is to say, after the main crop has been harvested and 

 before the succeeding one is sown. The practice of growing a crop of tares 

 or vetches after the wheat crop has been harvested is very common in 

 Europe, and can l)e followed successfully here in districts where the autumn 

 rainfall is sufficient. Such a catch crop occupies the ground only at a time 

 when it would be otherwise unoccupied, and, during its growth is collecting 

 plant-food from air and soil, which is utilised for manuring the succeeding 

 •crop. 



The practice of green-manuring is of special value in orchard work, where 

 the green crop can be grown and ploughed under between the rows. 



It must be borne in mind, in all cases, that green-manuring depends for its 

 success upon conditions favourable to the decomposition of the buried green 

 ■crop, namely, sufficient warmth and moisture. A crop ploughed under in the 

 late autumn or winter will nitrify owW slightly, and the same applies to 

 ploughing under a crop in a dry season. If the land is quite dry the crop 

 will remain buried without decom])osition for a considerable period, and its 

 benefit is lost. 



Proportion of Nitrogen supplied to Soil by Green Manuring. 



With regard to the actual amount of material supplied to the land by 

 ploughing under a green crop, some exjjeriments were carried out at the 

 suggestion of Mr. Allen, the Fruit Expert of the Department. 



The produce of one square yard of crops of vetches, at Wagga, Bathurst, 

 and Hawkesbury College, was harvested carefully, tops and roots, and for- 

 warded for analysis. In the case of the Wagga samph', the roots were 

 obtained by washing away the soil, and Mr. McKeown calculates that he 

 succeeded in obtaining 95 per cent, of the total weight of roots in the soil. 

 The produce of t()])s from one square yard was 4 lb. i\\ oz.. or 10 tons 

 12 cwt. per acre; and of roots, 1 lb. 9 oz. per square yartl, or 3 tons 7 cwt. 

 per acre. Analysis showed that the tops contained 87 per cent, water (13 

 per cent, dry matter), and "506 per cent, nitrogen; the roots contained 83 

 per cent, water (17 per cent, dry matter), and •213 per cent, nitrogen. 



When therefore, this crop is ploughed undci-. it will add to each acre of 

 the soil, in the shape of dry matter, 1 ton 7 cwt. tops, and Hi cwt. roots, 

 including 120 lb. nitrogen from tlie tops and Ki lb. iiitrojicn from the roots; 



