136 THE IRRIGATION AGE. 



understood, except that it possessed one important advantage: name- 

 ly, his strips being so narrow, and hence so numerous, that both the 

 moisture saved by the tillage and the nitrates developed became avail- 

 able to the plants growing along the margin. Further than this, a 

 part of the rain which fell upon the strips, both by its lateral capillary 

 movements and by the development of roots into this unoccupied 

 ground, contributed to the growth of the crop as though it had been 

 partially irrigated, or its rainfall had been increased, which in fact it 

 had. 



The Rev. Mr. Smith, at Lois-Weedon, in Northamptonshire, 

 raised wheat very successfully by still a different modification of Tull s 

 idea. His practice was to sow about one peck of seed to tb.3 acre, by 

 dropping the grains 3 inches apart in three rows 1 foot apart, and 

 leaving a space of 3 feet wide unplanted between each group of three 

 rows. These strips were thoroughly tilled until the wheat was in 

 bloom, and kept free from weeds. He even went to the extent of 

 trenching the naked strip, bringing up some of the subsoil and put- 

 ting the surface loam into the trenches. By his thorough tillage, 

 thorough aeration and conservation of soil moisture, he was able to 

 maintain a yield of 18 to 20 bushels per acre without manure. 



These cases of old and now generally abandoned practice are 

 called up here because they involve a principle w r hich, when correctly 

 applied, is of great importance in sub-humid climates, where water 

 for irrigation is not available. The principle referred to is that of 

 using the rain which falls upon an acre of ground to produce a crop on 

 one-half of that same area. For this, as a matter of fact, was the es- 

 sential thing which the Lols-Weedon system did. It is evident enough 

 that in a country where the rain which falls is only one-half the a- 

 mount which is needed to produce remunerative crops, if that water 

 can be brought to use on one-half of the area, then a fair crop on one- 

 half of the ground may reasonably be expected. 



The important matter, then, is to devise a system of planting for 

 the various crops which shall permit the rain which falls upon the un- 

 used area to be brought within reach of the plants growing upon the 

 occupied ground. For all crops which are grown in hills or in rows, 

 like maize, potatoes, and variou s vegetables, the problem is simple 

 enough, as it resolves itself into the single question of how many plants 

 can be nurtured upon the ground with the available water, allowing; 

 for unavoidable losses. This fixes the distance between the rows and 

 the distance between the hills in the row. In countries where there is 

 an abundance of water, or where irrigation is practiced, plants may be 

 brought so close together that the limiting factor is amount of sun- 

 shine, or available plant food in the soil or air about the plant; but in 

 sab-humid regions, the limiting factor is water alone, and the distance 

 between plants must be made such, if necessary, that the roots of one 

 not encroach upon the feeding ground of another. Hence it is 



