CULTIVATION. 85 



each plant, the manure is dissolved by the irrigation water 

 and passes downwards and inwards, since the centre of the 

 ridge is un watered. Hence none of the manure will pass to 

 the next ridge. When the water has passed down ascertain 

 distance it will be recalled owing to the surface soil becoming 

 dry when its water is evaporated. The water with the 

 manure dissolved in it will slowly be drawn upwards 

 directly in the path of the plant root. In passing up and 

 down, the manure-laden water keeps in contact with the 

 plant roots. When the soil is quite dry, the only manure 

 which will appear at the surf ace ^will be a slight deposit 

 between the original position of the manure and the top 

 of the ridge. The manure deposited between the plant 

 and the crest of the ridge will be of no further use to the 

 crop, as water will never be applied high enough to redis- 

 solve and carry it to the plant roots. The quantity of 

 manure rendered inactive in this way is exceedingly small. 

 If, however, the manure were applied along the drill, there 

 would be a deposit of inactive manure along the whole 

 crest of the ridge instead of only a little between the 

 plant and the crest. Some of the manure applied to the 

 bottom of the drill would pass over into the plantless side 

 of the neighbouring ridge, and there would be a greater 

 loss by drainage on sandy soil. 



On the centre ridge no manure has been applied : on 

 the outer, the manure has been broadcasted. The manure 

 up to the level of watering on both sides of the ridge is 

 dissolved, passing downwards and inwards with the irriga- 

 tion water. Part of the food solution will come into contact 

 with the roots of the plants, but much of it between the 



