46 GENERAL CONSIDERATIONS 



plowing with the hillside plow, year after year, con- 

 stantly tends to build up the outer line of the ter- 

 race and cut down the inner one, so that ultimately 

 the terrace becomes nearly level. This system, when 

 carefully followed, has much to recommend it,* and it 

 should be much more widely adopted in all hilly re- 

 gions. It is to be especially recommended for per- 

 manent plantings like orchards and vineyards. Coffee 

 plantations are usually made in steep hill lands, and 

 they should always be planted on some modification 

 of this system. 



On very heavy hillside soils, in regions where the 

 rainfall is excessive and the question of surface 

 drainage has to be considered, it is sometimes best 

 to lay out the rows or the terrace lines with a slight 

 but gradual fall, so as to slowly carry off the surplus 

 water instead of trying to hold it and make it all 

 sink into the ground. It is a difficult matter, how- 

 ever, to lay out the rows so that the water will run 

 freely and still not run fast enough to wash. While 

 the system is theoretically an ideal one, it seldom 

 works satisfactorily in practice, and it should only be 

 adopted after full consideration and usually after 

 some preliminary trials. The amount of slope to 

 give the rows will depend entirely on the nature of 

 the soil, and the amount of the surplus rainfall. 



Irrigation. — There are many regions where the 

 soils are well adapted to agricultural purposes, but 

 where the rainfall is insufficient or too irregularly 

 distributed to admit of the production of crops. In 

 fact it is a general rule that the richest lands are 

 found in dry countries where they have not been 



