72 ECONOMY OF FARMING. 



the earth, yet this wouli he equal to the third part ofmanuring it with stall-manure ; 

 and probably yet higher, since the wheat, alter a thick grown crop of clover, bears a 

 greater product than if a similar field, but badly stocked with clover, was manured 

 with 100 cvvt. of stall-manure. That all the clover roots may benefit the following 

 crop, the field mast be ploughed up deep with a well-set cutting-plough, because 

 otherwise the harrow tears up or merely exposes too many roots. 



23. The annual pod-bearing plants with small roots, if they are mowed 

 before the formation of the kernels, must be considered equal to the peren- 

 nials in respect to their need of humus ; but the roots which they leave in 

 the soil are too insignificant to be regarded. 



I see no sufficient reason why vetches and peas, if they should be mowed for fodder, 

 and only occupy the soil for a short time, should draw away to themselves more 

 humus than clover and luzerne. That vetches only slightly take away from the soil, 

 and that grain, which follows after vetches that have been manured and mowed 

 while green, is only a little inferior to that which is fresh manured, is universal expe- 

 rience. But the roots of peas and vetches are so small that they scarcely deserve 

 mention in the estimate of manure ; the roots of lentils and beans must be more 

 regarded. 



24. If the pod-bearing plants produce ripe grains, they need for the for- 

 mation of the same more manure; and we must bring the whole product 

 of the kernels into the estimate of manure. 



Every one knows that those fields which have borne ripe vetches, compared with 

 others where they were mowed in a green state, show themselves more enfeebled in 

 proportion. 



25. Should the grain plants of the grass-kind be cut before the kernelling, 

 then we must ascribe the formation of f of the whole product to the humus, 

 and only f to the unorganized matter. 



I allow that these statements of particular proportions appear arbitrary, because 

 they are grounded on no definite experience, but are only drawn from the estimate 

 of the quantity of manure for the production of rtie bodies of the plants. But if we 

 take for granted that plants usually appropriate inorganic matter, and that the grass- 

 xind of plants can do this in a less degree than the pod-bearing ones, so only can the 

 relative amount of the necessity of organic and inorganic matter in these two classes 

 of plants be a matter of doubt. We have reckoned of the pod-bearing plants, should 

 they be cut green, only one half of their product to the humus; and if we here bring 

 f- of the same into the account, yet we hold them not to be too much lessened and 

 the more so since these suppositions are placed in correct proportions in the following 

 paragraphs. 



26. If the grass-kind of grain-plants are cut in a ripe state, their whole 

 product in kernels and straw, must likewise be set down for the diminution 

 of the humus in the soil. 



The leaves drying up in a great degree are the special cause that the whole plant 

 is henceforth nourished only by the roots. The greater absorption of humus by the 

 roots, and its large evaporation from the soil which is less shadowed, than with the 

 husk-bearing plants or vegetables, are the principal causes why the soil is so much 

 exhausted by the culture of the grass-kind of plants. So, that there is always a 

 surplus of product to be taken into the account compared with the quantity of humus 

 employed, which at a close estimate probably exceeds 10 percent., cannot be doubted ; 

 but I have purposely overlooked it, because on the other side I have not brought into 

 the estimate the loss wliich the manuring substances undergo, partly in the bodies of 

 beasts which are fed upon them, partly during the processes of fermentation. 



[ Veit observes: "The grain fruits with their roots run through the whole upper 

 strata, and appropriate to themselves all the store of dissolved humus there existing. 

 After the time of kernelling. the leaves dry up; therefore the atmosphere operates on 

 the uncovered soil, draws out its moisture, forms a crust, enlivens the weeds, and 

 ripens them."; 



On the exhausting power of the different grains, Thaer remarks, that "according 



