42 PHILIPPINE AGRICULTURE 



ground cultivated 20 cm deep, if irrigated once in two 

 weeks; better than in ground cultivated 10 cm deep, 

 where it is watered every other day. 



At the Spanish experiment station in Albay, it was 

 found that during the dry season abaca grew better on 

 land prepared with an American plow before the abaca 

 was planted than it did where the Filipino plow had 

 been used. 



Although clay holds more water than sand does, it 

 usually dries deeper in dry weather, both because it be- 

 comes hard in such large blocks that the water cannot 

 move upward through it, and because it cracks badly. 



Mulching. The water which is in the soil when the dry 

 season begins is lost by evaporation, either from the sur- 

 face of the soil, or through plants. If all weeds are 

 killed, the loss of water by their transpiration is pre- 

 vented. The evaporation from the ground itself is made 

 the least possible by keeping the surface smooth and 

 even, and very fine. This surface is sometimes called a 

 "mulch." It is dry, and full of' air; but the air is quiet, 

 and does not move rapidly when the wind blows, as the 

 air does in a coarse, or rough, or cracked surface. In 

 the latter soils the air is constantly moving in and out, 

 and carrying out a great deal of moisture. Therefore, 

 cultivation, by making the soil fine, not only makes it re- 

 ceive water from deep in the ground, but prevents the 

 loss of this water from the surface. At the San Ramon 

 farm, a part of the abaca, which was planted in Spanish 

 times, is no longer in rows, and so cannot be cultivated 



