GREEN MANURE MOST USEFUL TO POOR AND SANDY SOIL. 419 



have already been discussed, and I may presume that you sufficiently 

 understand the principles and admit the fact. Living i)lants, then, 

 contain in their substance not only all they have drawn up from the 

 soil, but also a great part of what they have drawn from the air. 

 Plough in these living plants, and you necessarily add to the soil 

 more than was taken from it — in other words, you make it richer in 

 organic matter. Repeat the process with a second crop and it be- 

 comes richer still — and it would be difficult to define the limit beyond 

 which the process could no further be carried. 



Is there any soil then, in the ordinary cUmates of Europe, which is be- 

 yond the reach of this improving process ? Those only are so on which 

 plants refuse to grow at all, or on which they grow so languidly as to 

 extract from the air no more than is restored to it again by the natu- 

 ral decay of the organic matter which the soils already contain. 



But for those plants which grow naturally upon the soil, agricultural 

 skill may substitute others, which will increase more rapidly, and pro- 

 duce a larger quantity of green leaves and stems for the purpose of being 

 buried in the soil. Hence, the selection of particular crops for the pur- 

 pose of giving manuring — those being obviously the fittest which in the 

 given soil and climate grow most rapidly, or which produce the largest 

 quantity of vegetable matter in the shortest time and at the smallest cost. 



§3. Of the plants which in different soils and climates are employed 

 for green manuring. 



On this prmciple is founded the selection o^ different plants in different 

 soils and climates for the purpose of green manuring. That which 

 in Italy will yield the largest produce of leaves and stems, at the least 

 cost, and in the shortest time, may not do so in the North of^ England or 

 of Germany — and that which will enrich a poor clay or an exhausted 

 loam may refuse even to groW; in a healthy manner, upon a drifting sand. 



1°. Spiirry (Spergula Arvensis.) — It is to poor dry sandy soils that 

 green manuring has been found most signally beneficial, and for such 

 soils no plant has been more lauded than spurry. It may either be 

 sown in autumn on the corn stubble or after early potatoes, and 

 ploughed in in spring preparatory to the annual crop, or it may be 

 used to replace the naked fallow, which is often hurtful to lands of so 

 light a character. In the latter case, the first sowing may take place 

 in March, the second in May, and the third in July— each crop being 

 ploughed in to the depth of three or four inches, and the new seed 

 then sown and harrowed. When the third crop is ploughed in, the 

 land is ready for a crop of winter corn. 



Von Voght (Vortheile der griinen Bediingung) states that by such 

 treatment the worst shifting sands may be made to yield remunerative 

 crops of rye — that the most worthless sands are more improved by it 

 than those of abetter natural quality — that the green manuring every 

 other year not only nourishes sufficiently the alternate crops of rye, 

 but gradually enriches the soil — and that it increases the effect of any 

 other manure that may subsequently be put on. He adds, also, that 

 spurry produces often as much improvement if eaten off by cattle as 

 if ploughed in, and that when fed upon this plant, either green or in 

 the statti )f hay, cows not only give more milk, but of a richer quality. 

 18* 



