Cultivation of Grafs Land. Watered Meadows- How improved. 443 



long in ufe in other countries, and of late more particularly attended to in this, 

 the principle on which it produces its effects does not feem to be fully undcrflood.. 

 In fpcaking of manure as the food of plants, we have already noticed fome of the 

 properties of this fluid that may be ufeful in the vegetable economy when taken 

 up by the fibrous roots of plants, and there are (till other ways in which it would 

 feem to be advantageous in forwarding the growth of grafs crops. 



In climates where the heat is considerable it may be of much utility, not only by- 

 keeping the fine fibrous roots of the grafs or other plants in a moid patulous (late,, 

 the moft proper for the purpofes of abforption, but in fuch a temperature or (late 

 of hear, from the cooling effect produced by theconftant evaporation that is taking 

 place near the furface of the ground, as is the mod fuitable for their healthy and 

 vigorous growth. It is probably in this way that garden plants are principally 

 benefited by the application of water in the hotfummerfeafons in our own climate, 

 as when the waterings are not conftantly kept up, injury rather than good is moft- 

 ly experienced. 



But another and more beneficial way in which grafs produce may be immediate 

 ly increafed,and the fertility of the lands more permanently improved in this coun* 

 try by the floating or covering them with water, is from the waters of the rivers or 

 brooks that are turned upon them containing, either in theftate of folutionor dif- 

 fufion, a variety of different forts of enriching materials which they gradually and 

 evenly depofit upon the furface while they reft upon or flowly flow over it. This 

 tnuft be the cafe in all thofe inftances where the rivers or ftreamlets either arife 

 in, or in their courfe flow through or over beds of chalk, marl, or other calca 

 reous ftrata, as in their paflage they become highly impregnated with the fine 

 particles of thefe different fubftances. And where they are fed by the fmali 

 runlets which receive the waters that proceed from the higher and more elevated 

 lands, they muft often, efpecially after heavy rain, be loaded with a large propor 

 tion of fine rich materials of the animal, vegetable or other kinds, which they 

 depofit in a regular manner in their tardy trickling courfe over the furfaces of the 

 fields. 



$ut it would appear that waters thus impregnated produce the moft beneficial 

 effects, particularly when not in flood, upon the lands that are the nearcft to the 

 fources whence jthey become principally impregnated with their fertilizing princi 

 ples ; as when they have flowed to forne diftance they have, in a great meafure, 

 depofited and let fall fuch enriching fubftances, and are become too pure for 



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