Extirpation of Weeds. 253 



as to induce them to germinate, and then to destroy the plants" by harrowing up 

 or ploughing under. This is strictly true, but I do not exactly agree with him in 

 the process; the ground, for this purpose, should be ploughed before winter, but 

 not harrowed, it being better to lay rough through that season, so as to have the 

 greatest extent of surface possible exposed to the mellowing of frosts ; as soon as 

 it becomes dry in March, it should be cross-ploughed and harrowed down; many 

 of the seeds and roots will then vegetate, which should in due time be ploughed 

 under and harrowed again, and this process repeated as often as necessary : this is 

 the true use of summer fallow, which, to have its proper effect, should always be 

 attended to early in the season, when the powers of vegetation are greatest, and the 

 heat of the sun is powerful. 



The great defect in the management of summer fallows, seems to be the neglect 

 of working them early in the season, by which omission, the vigorous annual seed- 

 ling weeds are not brought into vegetation in due time, after which they will not 

 grow till the spring following, when they appear in such abundance amongst the 

 wheat as sometimes to choke the crop ; this is the reason why the poppy, the corn 

 crowfoot, the tare, and many other annual weeds, make such havoc amongst wheat, 

 when by a judicious early working the fallow, they might have been brought to 

 exhaust themselves in the fallow summer: this appears very clear from the effect, 

 for if no wheat were sown, the seeds of these plants would often fill the ground 

 with a full crop ; but seeds can vegetate but once, consequendy, had this vegetation 

 been brought on in the fallow, and the plants afterwards been ploughed under in 

 due time, none could have appeared in the wheat crop. 



The turnip culture is peculiarly adapted to the destruction of weeds, as for this 

 crop the ground must of necessity be in early preparation, by which weeds of early 

 growth are brought into vegetation and destroyed, and those which remain alive 

 in the soil may be exterminated by hoeing. I have observed that wet weather is 

 as necessary as dry to give a summer fallow its whole effect ; for without a soaking 

 of rain after the land is pretty well pulverized, numbers of the seeds will not vegetate, 

 but remain and grow amongst the crop ; the root weeds are therefore to be destroyed 

 in dry weather, and the seedlings after rain; and though the land shoi Id after a dry 

 season be apparently in excellent order for sowing, it is better to wait the effect of 

 rain, and even give time for seedlings to vegetate before you actually sow for the 

 crop. 



