378 CULTURE OF FARM CROPS. 



the season is a good one, this may be done so early as to 

 admit of a " stolen crop " being taken from the land before 

 the regular crop is put down. In place, however, of plough- 

 ing up the clover lay after it has occupied the land for one 

 year only, it may be allowed to remain for two years' 

 growth in which case it should be well manured with 

 farm-yard manure, compost, or artificial manures. Of late 

 years the clover crop has been subjected to the attacks of 

 disease known as the clover sickness. Much has been 

 written about the cause of this and the means to be adopted 

 for its prevention; opinion, however, is by no means de- 

 cided on the question. The following, on it, is from the 

 paper by Professor Buckman, from which we have already 

 quoted : 



" If we look at both artificial grasses and clovers, 

 we shall find that this term applies to them in another 

 sense from the one usually understood, namely, in being 

 derivative plants. The Lolium perenne has been grown 

 into many varieties, as " Whitneyworths, Stickneys, Rus- 

 sells, and Pacey's Kay," and in all probability even the L. 

 Italicum is but a variety of the L. pcrenne, and, as its 

 variorum forms, are the result of external circumstances, 

 and only more or less permanent, so that its permanency 

 in any one position depends wholly upon the suitability 

 of these conditions, so that what will hold to the soil in 

 one position will not do so in another, for, being wholly 

 cultivated plants, they can only exist as they are under 

 suitable cultivative impressions, and are, as a consequence 

 of this, daily becoming less suitable for a milder kind of 

 life, and so less permanency is to be expected. 



" These remarks apply with still greater force to clovers 

 accustomed to seed on the soil in their wild state. We 

 collect the seed and keep it all the winter, in itself a culti- 

 vative process ; and then it is sown with other plants in a 

 prepared soil. And though by these means it increases in 

 size, yet it has also a changed constitution, and so the 

 variety that will be permanent in one place will not in 

 another; and thus, when we cannot secure a crop, we call 



