50 GARDEN FARMING 



or early in the spring and plow it under ; but when well-decom- 

 posed stable manure is available, it should not be applied until after 

 the rough ground has been plowed and harrowed. Stable manure 

 has the decided advantage over chemical manures, not only of be- 

 ing an almost complete fertilizer in itself, but also of having a most 

 beneficial mechanical effect on the soils to which it is applied. This 

 mechanical effect cannot be obtained by chemical manures, for they 

 add nothing in the way of organic matter to the soil. Stable manure, 

 however, adds to the soil a considerable amount of organic matter, 

 which tends not only to change the color of the soil somewhat, but to 

 lighten it, making it warmer, more retentive of moisture, and capa- 

 ble of better drainage. For many soils these mechanical and physi- 

 cal effects are of quite as much importance as are the fertilizing 

 ingredients themselves. It is never a good policy in truck farming 

 to rely upon artificial or chemical manures alone. They should be 

 supplemented to the fullest possible extent by stable manure and 

 by plowing under green crops, such as cowpeas, rye, buckwheat, 

 etc. The rule should be to keep the soil always covered by a crop, 

 no matter if it is necessary to plow it under within a few weeks 

 after sowing. 



Irrigation. The importance of a controllable water supply has 

 already been pointed out. It is absolutely necessary in greenhouse 

 and frame work and is of much more importance in outdoor opera- 

 tions than is generally realized. Irrigation is essential to crop pro- 

 duction in arid regions, but in humid sections it has not been 

 considered necessary for most crops. Irrigation or a controlled 

 water supply is one of the greatest crop insurances that can be pro- 

 vided even where humid conditions prevail. It often happens that 

 a single irrigation at just the right time will save a crop, prolong 

 its harvest period, or safeguard it against frost. In humid regions 

 irrigation is a form of insurance to be used in case of accident. 



Two methods of applying water are open to the vegetable grower : 

 the sprinkler system, which has many modifications and adapta- 

 tions, and the furrow system. Flooding is seldom employed in 

 truck farming, the one notable exception being in Texas in con- 

 nection with the seed beds for Bermuda onions. 



The sprinkler system. This system of irrigation requires the 

 water to be carried in a closed receptacle under considerable 



