260 DIRECT SOWING. 



the second difference makes it obligatory to follow horizontal 

 contours in tracing the trenches and furrows, for any slope, one 

 way or the other, of their bottom must convert them into water- 

 courses or at least cause the soil and seeds to be washed down 

 from the higher to the lower points and the seedlings to be exposed 

 or entirely uprooted. In excavating the furrows aud trenches the 

 use of levelling intruments is indispensable, unless they are made 

 in such short lengths (up to a maximum of about 10 feet) that 

 work with the unaided eye would not result in a difference of 

 level exceeding say 2 inches. The large wooden triangular level 

 described on p. 226 would be a very suitable implement to use. 

 On slopes the maximum of 10 feet should be carefully observed. 



Trenches differ from furrows in that they have more or less 

 vertical sides and are generally deeper in proportion to their width, 

 while the latter have more or less gently sloping sides and are 

 deepest along the middle. 



1. Width and depth of the furrows and trenches. 



In the dry soils and localities in which this system has its raison 

 d'etre, not only is the growth of weeds never heavy but eveiy 

 bit of whatever comes up is useful and even necessary to protect 

 both the soil and the sowings. Hence the width of the furrows 

 and trenches should never exceed 2 feet, and should be regulated 

 principally by their depth, which itself will depend on the amount 

 of moisture that they should be able to catch and hold, on the 

 porous nature of the soil, and on the abundance of rain or other 

 source of moisture. Usually the width will vary from 10 to 20 

 inches, the depth being about half the width. 



2. Preparation of the furrows and trenches. 

 Furrows may be made with a special plough or with a pick or 

 hoe, according to the nature of the ground, while trenches must be 

 excavated with hoes and picks, even if the soil has been first of all 

 loosened with a plough. In any case, the soil at the bottom should 

 be loose and rich in order to form a good seed bed, and to this end 

 the trenches and furrows should be excavated beyond the depth 

 fixed for them, and the bottom should be filled with the good top 

 soil removed. The rest of the excavated earth should be heaped 

 up along one edge either on the side on which the seedlings will 

 require shelter against unfavourable weather influences, or, if the 

 ground has a pronounced slope, along the lower 'edge. Where 

 picks and hoes are used, much time and money are saved by form- 

 ing the bottom of each excavation with the top-soil obtained 



