30 



But in regard to fallowing a difficulty at once arises. While 

 the land is lying fallow it is subject to loss of nitrates by leaching; 

 indeed one of the great merits of green manuring is that it puts a 

 crop on the land in autumn when the stock of nitrates is high and 

 the crop takes up the nitrates and holds them safely from the winter 

 rain. A simple way round the difficulty is to have the necessary 

 fallow only during the dry weather, and it so happens that all our 

 experiments were made under these conditions. 



It is to clear up these and similar problems that a definite 

 green manuring experiment has been begun. A field is divided 

 into four parts, one of which is farmed with artificials only, one 

 with farmyard manure and artificials, and two with artificials and 

 green manure but no farmyard manure. One of the two last 

 carries leguminous crops and the other non-leguminous crops for 

 the green manure. An eight-year rotation has been drawn up 

 to keep the green-manured land as closely cropped as possible, and 

 to reduce to a minimum all losses by leaching ; whether other losses 

 will also be reduced has yet to be determined. The eight-year run 

 should show how far green manuring can be regularly practised 

 under farming conditions, and whether periodical fallows will be 

 necessary. 



Meanwhile, in view of the marked benefit just recorded of the 

 fallow coming after the lucerne ley and of other results of like nature, 

 the question arises whether, in a dry summer, it is worth while to 

 trouble about the aftermath of the seeds or clover ley (unless wanted 

 for clover seed), and whether it would not be better to take the first 

 cut early and plough up immediately so as to secure a long bastard 

 fallow before the next corn crop. Under dry conditions the after- 

 math may be worth only little, while the benefit of the fallow is great. 

 The practical difficulty on a heavy loam like ours consists in break- 

 ing up a hard baked ley at midsummer sufficiently quickly to avoid 

 interference with other work. Not only for this purpose, but for the 

 general object of being well forward in autumn, there is great need 

 on medium sized heavy-land farms of a plough which will cheaply 

 and efficiently do more than the one acre a day that has for untold 

 years been considered the ploughman's proper and sufficient duty. 



MIXED CROPS. 



The harmful effect of some growing crops on others observed 

 by Mr. Pickering, at Woburn, gives an added interest to the study 

 of weeds. Hitherto it has been supposed that weeds are mainly 

 harmful through depriving the plant of water, food, and root space, 

 but Mr. Pickering's observations indicate that there is something 

 more. Pot experiments have therefore been started and careful 

 field observations taken to ascertain the importance of these effects 

 in practice. We must know the real case against weeds before we 

 can decide how much it is worth spending in order to eliminate 

 them. 



It does not always appear that one crop injures another. It is 

 not uncommon in the west country for farmers to grow a mixture 

 of oats and barley as dredge corn, and it is commonly stated that the 

 yields are larger than when the two are grown separately. An 

 experiment with the mixture has therefore been made at Rothamsted 



