22 THE PARK 



supplying phosphoric acid, potash, magnesia, and soda, is used ; Plot 8 has 

 received the same application, but without potash, since 1861, while Plot 

 4-1 receives superphosphate only. With the complete minerals a fair crop 

 is grown, averaging over 1 J ton of hay for the first cut alone. The reason 

 that the crop on this plot is maintained, although no nitrogen is supplied 

 in the manure, lies in the free growth of leguminous plants. It will be 

 seen that, taking the average over the whole period, the leguminous plants 

 form 24 per cent, of the herbage, and the proportion has increased from 

 year to year. 



The omission of potash on Plot 8 has caused a very striking difference 

 both in the crop and in the character of the herbage. The average crop 

 has been about one-quarter less over the whole period, and shows a pro- 

 gressive decline in fertility, until at the present time it is little more than 

 half that of Plot 7. The poor results on this plot, as compared with 

 Plot 7, must be put down to its poverty in leguminous herbage, the 

 development of which seems to depend on a free supply of potash. Of late 

 years the proportion of leguminous plants on this plot has amounted to 

 about one-half of that found on Plot 7, the grasses are about the same, the 

 difference being made up by an increased amount of weed. 



Plot 4-1, which each year has received superphosphate only, now pre- 

 sents a very impoverished appearance, and is giving no more crop than the 

 unmanured plots. Indeed, the aspect of this plot, where the most 

 abundant grass is Quaking Grass, and where weeds, chiefly Hawkbit, 

 Burnet, and Plantain, are unusually prominent, would seem to indicate 

 that the land is more exhausted here than on the unmanured plot. 



Complete Manures — Nitrogen and Minerals 



Among the plots which receive both nitrogenous and mineral manures. 

 Plot 9, with a complete mineral manure and ammonium-salts should be 

 compared with Plot 14, which is exactly similar except that the nitrogen 

 is applied in the form of nitrate of soda, and again with Plot 16, where 

 only half the amount of nitrogen is applied, but again as nitrate of soda. 

 The nitrate of soda gives the heavier yield, the herbage is also more 

 diversified, and there is not the total absence of leguminous plants which 

 marks the plots receiving ammonium-salts. Two characteristic plants. 

 Soft Brome Grass and Beaked Parsley, are found only on the plots 

 receiving nitrate of soda, the corresponding umbelliferous plant where 

 ammonium-salts are used being the Earth Nut (Conopodium). 



On Plot 11 the same mineral manures are applied with an extra amount 

 of ammonium-salts, so that the nitrogenous manuring is excessive. As a 

 result the vegetation consists entirely of tufts of three coarse grasses — 

 Meadow Foxtail, Yorkshire Fog, and Tall Oat Grass. The soil has also 

 become sour and unhealthy, with the result that the plant is dying in 

 patches, except on the upper portion of the plot where lime has been 

 applied, and on the half numbered 11-2 where the silicate of soda is 

 used. 



The effect of omitting potash from the complete manure is seen on 

 Plot 10, and again on Plot 4-2, where superphosphate and ammonium- 

 salts only are applied. It is noticeable that the grass on these plots is 

 weak in the straw and liable to fungoid attacks. 



