IJ2 CALCAREOUS MANURES-PKAC IICE. 



a cover of annual weeds. Yet on otlier tillage land, after marling and one 

 crop of wheat on fallow, I have seen the growth of broom-grass return, 

 and seemingly with greater than its former vigor. But this return and 

 vigor were but temporary, and the land is now comparatively free from this 

 injurious weed. When soil, already filled with its seeds, is very imperfectly 

 mixed with marl by ploughing, these is nothing to prevent the broom-grass 

 springing from all the spots not touched by the marl, whether these spots 

 be above or below or between unmixed masses of marl. And the growth 

 being thin and scattered, and not covering the surface completely as for- 

 merly, will cause the separate tufts of broom-grass to be much more luxu- 

 riant, and greater impediments to tillage, than previously. But the next 

 course of tillage will serve to mix the marl and soil completely, and remove 

 all appearance of marl being favorable instead of destructive to broom- 

 grass. Sorrel may often be seen growing out of the heaps of pure marl, 

 dropped from the carts on acid land, and the heaps left thus, unspread, 

 through a summer. But this apparent and very striking exception may 

 be fully explained. The heaps of marl, thus left, had not as yet by any in- 

 termixture affected the original composition of the soil below ; and the 

 seeds or roots of sorrel therein were therefore free to spring and grow ; 

 and the great hardiness and remarkable vital power of that plant enabled it 

 to rise through the (to it) dead matter and great obstruction of several 

 inches thickness of pure marl above. On examining the roots of sorrel 

 thus growing out of marl, it will be seen clearly, and invariably, that they 

 drew all their support from the still acid soil below, and merely passed 

 through the m^arl, without drawing any thing therefrom. 



CHAPTER Xr. 



RECAPrrULATION OP EFFECTS, AND DIRECTIONS FOR PRACTICE CONTINUEH. 



Proposition 5 — continued. 



If the foregoing views may be confided in, the general course most pro- 

 per to pursue in using calcareous manures may thence be deduced without 

 difficulty. But as I have found, since the publication of the previous edition 

 of this essay, that many persons still ask for more special directions to guide 

 their operations, and as all such difficulties may not be entirely obviated 

 even by the more full details now given, I will here add the following di- 

 rections, at the risk of their being considered superfluous. These direc- 

 tions, like all the foregoing reasoning, may apply generally, if not entirely, 

 to the use of all kinds of calcareous manures, and to soils in various re- 

 gions; but to avoid too wide a range, I shall consider them as applied par- 

 ticularly to the poor lands of the tide-water region, and addressed to per- 

 sons who are just commencing their improvement by means of the fossil 

 shells or marl of the same region. 



As the cheapest mode of furnishing vegetable matter to land intended to 

 be marled and cultivated, no grazing should be permitted. It is best to 

 put the marl on the grass previous to ploughing the field for corn, as the 

 early effect of this manure is greatest when it has been placed in contact 

 with the vegetable matter. But this advantage is not so great as to induce 

 the ploughing to be delayed, or to stop the marling after that operation. 



