36 THE ESSEX EXPERIMENTS 



beginning of May until the third week in June made a hay crop out 

 of the question, and the plots were therefore grazed by cattle and 

 sheep during the remainder of the season. The contrasts between 

 several of the plots were, however, so great, that on the suggestion 

 of Dr Russell a detailed examination of the ground space covered 

 by the various types of vegetation was made on several of the plots, 

 using the method recommended by Armstrong (i). 



The results are set out in Table XV, and illustrated in Fig. 4. 

 Photographic representations of several of the plots are given in 

 Plates VII and VIII. 



The poverty of the untreated plots is difficult to describe, but some 

 idea of their unproductiveness is afforded by Table XV, by Fig. 4 

 and the lower figure on Plate VI. Amongst the weeds on the un- 

 treated plots Hypochaeris radicata, Leontodon hispidus, Ranunculus, 

 Prunella vulgaris, Potentilla reptans, Bellis perennis and Plantago 

 lanceolata are prominent, and amongst the grasses Holcus lanatus, 

 Hordeum pratense, Agrostis vulgaris, Cynosurus cristatus, Lolium 

 perenne are also prominent, whilst traces of Dactylis glomerata, 

 Phleum pratense and Alopecurus pratensis can be found. 



The transformation which has been brought about by the various 

 phosphates is remarkable. Weeds have been largely crowded out and 

 the bare space reduced in some cases to vanishing point. On the 

 untreated plots the crop was left practically untouched, whilst on 

 the plots receiving phosphates the growth had been grazed to the 

 ground, and even the clover runners were being eaten by the sheep. 

 The contrast remained equally striking right through the whole 

 winter. The untreated plot was clearly defined by its dark unhealthy 

 appearance and the black heads of the uncropped crested dog's tail. 

 On the plots receiving phosphates the mat of wild white clover 

 runners remained green throughout the whole winter, and continued 

 to afford feed for the stock wintered on the meadow. 



The botanical examination of the flora reveals differences between 

 the various phosphates which do not appear so prominently in 

 the yields of hay. Whilst the various basic phosphates show but 

 small differences, the three plots receiving superphosphate show 

 significant contrasts. A very decided improvement has followed the 

 heavy dressing of superphosphate, but the small dressing of 50 Ibs. 

 of P 2 O 5 in the form of superphosphate has had little effect. The 

 addition of lime at the rate of 1 ton per acre, sown immediately the 

 superphosphate had passed through the drill, produces an effect which 

 affords a significant contrast with the same dressing of superphosphate 



