FIELD CROPS. 



The result- of experiments in growing, curing, and fermenting tobacco are reported, 

 and ways and means for the improvemenl of the Porto Rican crop are suggi 

 Mechanical analyses of soils and subsoils from typical Porto Rican tobacco fields, 

 as determined by the Bureau of Soils of tins Department, are given in tables and 

 discussed. The mechanical analyses of subsoils from 2 Cuban tobacco districts are 

 also given. 



In seed-bed experiments it was found thai the Beed under shade came up from •_' to 

 1 days earlier than the seed without shade; hut while the shaded seeds came up 



earlier and looked healthier during the first '■'> week-, those without shade were 



finally more vigorous and larger. The shade reduced evaporation, resulting in a 

 quicker and more perfect germination of the <>'r<\, and also protected the beds h 



washing. Cloth was more satisfactory for shade than straw. 



The burrows of changas in the seed bed were treated with a solution of I pari of 



kerosene to 14 parts of water, and no further depredations were noticed. When the 



plants suffered from disease a dilute solution of Bordeaux mixture was applied with 



very beneficial results. 



Transplanting experiments were made outside and under cover. In the open 

 mamey and mango leaves were us< d for shading. The petiole of the leaf was -tuck 

 into the ground 1 to 2 in. south of each tobacco plant to shield it from the direct 

 rays of the sun during the hottesl part of the day. Of 445 plants protected in this 

 way 125 died, and of the same number of unprotected plants 300 failed to grow. At 

 harvest the shaded plants showed a much greater uniformityin growth than the 

 unprotected ones. Of 300 plants wrapped in mamey leaves as a protection againsl 

 cutworms and mole crickets 200 died, and of the same number unprotected 220 had 

 to he replanted. Wrapping the plants is a protection againsl the crickets, hut it is 

 often detrimental to early growth because it confines the upper roots of the plant 

 and allows water to collect within the leaf. 



The poor results" in these two experiments were largely due to insufficient care in 

 planting and the use of unselected seed. In a trial under cheese cloth only about •"> 

 per cent of 1,700 carefully set-out plants failed to grow, while in a plat of 800 plants 

 planted in the usual native way the loss was much greater. 



An experiment in shade-growing wrapper leaf suffered from delays and disease 

 attacks, hut the results of this test as well as those of a second experiment indicated 



"that shading increases the yield, quality, and percentage of wrappers sufficiently 

 to make shading a profitable business, providing it is practiced only on soils suitable 

 for growing wrappers and the crop is given the best of care throughout its growth 

 and further treatment in curing and fermentation." 



Fertilizer experiments carried on at Aibonito showed that on that particular soil acid 

 phosphate was more efficienl than sulphate of potash or nitrate of soda combined. 

 The I! substances were applied at the rate of 60, 20, and 20 lbs. per acre, respectively. 



The use of 200 lbs. of lime in addition to the complete application showed no improve- 

 ment. In another test 2,000 lbs. of cotton-seed meal produced a better growth, 

 especially in the young plants, than a liberal dressing of compost of horse manure and 

 vegetable matter, including tobacco stems. The use of fertilizers for tobacco in Porto 

 Rico is disciis-ed. 



Curing experiments were made in.') curing sheds, the first a frame building con- 

 structed for a storehouse, the second a shed of poles and canvas covered by a straw 



roof, and the third a large .-lied constructed of hoard sides with a thatched roof on a 



pole framework. The daily temperature and relative humidity were ascertained in 

 each shed from March L9 to April 23. 



In the frame building, with a mean temperature of 80.2° F. and relative humidity 



of 68.3 per Cent, the tobaCCO dried too quickly and the leaves when cured contained 



many green spots. In the cloth shed the temperature was at first much too high 

 and the tobacco was badly damaged, hut when the mean temperature was down to 



