322 PEAR GROWING IN CALIFORNIA. 



twenty-four houys, the time depending upon the character of the soil, 

 will usually result in a good irrigation. Deep ditches are to be pre- 

 ferred to shallow, especially on heavy soils which are more or less 

 impervious. To prevent washing the furrows are sometimes curved. 

 It is a common practice to run them around the trees thus insuring 

 better wetting of the entire root system. 



The basin system is used generally in the large pear growing districts 

 of the Sacramento Valley. This is a flooding system by means of 

 small levees constructed at right angles to each other between the tree 

 rows, forming square or rectangular basins in which the water is 

 allowed to remain for the desired time. On the lighter types of soils, 

 at least, this system is quite satisfactory. In order to prevent baking 

 the cultivator must be used after irrigation by the basin method. This 

 is particularly necessary in the case of heavy soils. If the cultivator is 

 not used, the soil bakes and cracks, the moisture is rapidly lost, and 

 the physical condition of the soil is impaired. No stated time can be 

 given for the application of water. If the supply is plentiful it should 

 be used only when an examination of the soil reveals the need. In some 

 cases irrigation will necessarily have to be done when water is available. 

 In general two or three irrigations throughout the season -are desirable. 



CULTIVATION. 



Successful pear growing is accomplished in parts of California 

 without irrigation where it has not been possible to develop a supply of 

 water. The conservation of moisture in such cases is the prime 

 requisite of success. There is nothing else that will conserve the mois- 

 ture as well as frequent cultivation, whereby the soil is rendered fine on 

 the surface. A dust mulch, five or six inches deep, should be the aim in 

 cultivating such orchards. By using the cultivator once a week or 

 oftener the capillarity of the soil is broken and the moisture thus 

 prevented from reaching the surface and being lost through evapora- 

 tion. Cultivation, while being necessary in this case, is also desirable 

 in keeping down weeds, which should not be allowed to grow when 

 there is a scarcity of moisture and the trees need all that the ground 

 contains. Too little cultivation is given most of the unirrigated 

 orchards and the loss of moisture and suffering of trees from drought 

 in the fall of the year, which is so evident at certain times, could be 

 prevented by judicious cultivation. The principle involved, while 

 simple, is little understood by many orchardists and there is a prev- 

 alent notion that less moisture is lost if there is no cultivation. 



COVER CROPS. 



The subject of cover crops is one of great importance in every 

 orchard community, and the requirements are practically the same for 

 the pear orchard as for all other orchards. In California a fortunate 

 condition exists that does not apply to the other states of the Union. 

 That is, during the winter or rainy season cover crops may be grown in 

 the orchard to good advantage. This is not true in all parts of Cali- 

 fornia but is true in the main pear growing sections, where frequently 

 burr clover grows luxuriantly with little or no attention. Humus 



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