290 CITRUS FRUITS AND THEIR CULTURE. 



The root system spreads out well from the plant and 

 the roots penetrate the soil deeply. The tubercles formed 

 by the nitrogen-fixing bacteria are very large, frequently 

 an inch and a quarter or more in diameter, black or 

 brownish black, and covered with projections. (Fig. 67). 



The seed should be sown not later than the end of 

 May and earlier if possible. The crop is benefited by cul- 

 tivation, as it is somewhat slow in starting and the weeds 

 should be kept down until it is well established. Cultiva- 

 tion may be continued for three or four weeks after plant- 

 ing. While the seed may be sown broadcast, it is better 

 to sow in drills, four or five feet apart, or in hills, three 

 or four beans to the hill in checks four or five feet square. 

 One bushel is sufficient seed for four acres. They should not 

 be planted closer to the tree row than six or eight feet and 

 care must be exercised to turn the vines away from the 

 trees, else they may cover and smother them. This has 

 happened in the groves of careless cultivators. 



Baron H. von Luttichau, of Earleton, has been very 

 successful with velvet beans as a cover crop. His method 

 of handling it, as given in his own words in Bui. 69, Flor- 

 ida Experiment Station, is well worth reproducing here: 



"Since our first big freeze, when all the trees went, 

 I handle my groves in a different way from w^hat I had 

 up until that time. The velvet bean was introduced and 

 with that, the change. Until then my groves were worked 

 and fertilized according to established rules. 



"Last w T eek in January, or thereabouts, before the 

 bloom and growth starts, the plow is run, very shallow, 

 straight along six feet away from the tree rows. The 

 strip between the trees is left, never being disturbed, 

 either by plow or hoe. Nothing further is done until 

 about March 1st, when all the rest of the land and the old 



