148 NON-ACTION OP GYPSUM ON ACID SOILS. 



profitably used are much more exposed to sea air. Sucli are the 

 rich neutral soils of Curie's Neck, Shirley, Berkley, Westover, 

 Brandon, and Sandy Point, on James river, on all which gypsum 

 on clover has been extensively and profitably used, In advance of 

 marling or liming. On acid soils, I have never heard of enough 

 benefit being obtained from gypsum to induce the cultivator to ex- 

 tend its use further than making a few small experiments. When 

 any effect has been produced on an acid soil (so far as known from 

 my own experience, or the information of others), it has been 

 caused by applying to small spaces comparatively large quantities ; 

 and even then, the effects were neither considerable, durable, nor 

 profitable. Such have been the results of many small experiments 

 made on my own acid soils and very rarely was the least percepti- 

 ble effect produced. Yet on some of the same soils, after marling, 

 the most evident benefits have been obtained from gypsum on 

 clover. The soils on which the 1st and 10th experiments were 

 made (at some distance from these experiments) had both been 

 tried with gypsum, and at different rates of thickness, before marl- 

 ing, without the least effect. Several years after both had been 

 marled, gypseous earth (from the bed referred to, page 144) was 

 spread at twenty bushels the acre (which gave four bushels of pure 

 gypsum*) on clover, and produced in some parts a growth 1 have 

 never seen surpassed. It is proper to state that such results have 

 been produced only by heavy dressings. Mr. Thomas Cocke, of 

 Tarbay, in the spring of 1831 sowed nearly four tons of Nova 

 Scotia gypsum on clover on marled land, the field being a continua- 

 tion of the same ridge that my 1st, 2d, 3d, and 4th experiments 

 were made on, and very similar soil. His dressing, at a bushel to 

 the acre, before the summer had passed, produced evident benefit, 

 where it is absolutely certain, from abundant previous experience, 

 that none could have been obtained before marling. 



On soils naturally calcareous, I have in some experiments greatly 

 promoted the growth of corn by gypsum, and have doubled the 

 growth of clover on my best land of that kind. When the marl 

 containing gypsum was applied, benefit from that ingredient was 

 almost certain to be obtained. 



All these facts, if presented alone, would seem to prove clearly 

 the correctness of the opinion, that the acidity of most of our soils 

 caused the inefncacy of gypsum, and that the application of calca- 

 reous earth, which will remove the acid, will also serve to bring 

 gypsum into useful operation. But this most desirable conclusion 

 is opposed by the results of other experiments, which, though 

 fewer in number, are as strong as any of the facts which favour that 



* There was very little of the gypseous earth so rich as this limited 

 layer which was soon all removed for use. 



