"In the effect of _guano_, especially the Peruvian, I have never been disappointed. I have used it now for four years, with entire satisfaction having each year been induced to enlarge my expenditure, until last year it reached eight hundred dollars, and for the crop of wheat this fall it exceeds one thousand. I have observed with astonishment its effect in numerous instance on the poor "forest lands" alluded to in a former part of this address. What the turnip and sheep husbandry have done for the light lands of Great Britain, the general use of guano promises to do for ours. Lands a few years ago deemed entirely incapable of producing wheat, now produce the most luxuriant crops. From 15 to 20 bushels for one sowed, is the ordinary product on our poorest lands, from the application of 200 lbs. of Peruvian guano. I may remark, it is not usual, in Eastern Virginia, to sow more than a bushel of wheat to the acre, and that I deem amply sufficient. Upon this subject I hope a few details may not be considered tedious or uninteresting. I applied last fall $350 worth of guano, partly Peruvian and partly Patagonian, on a poor farm "in the forest," which cost a few years ago four dollars an acre, and reaped 1089 bushels of beautiful wheat from 78 sowed. Forty-six bushels were sowed on fallow, (both guano and wheat put in with the cultivator, followed by a heavy harrow,) and yielded 790 bushels or over 17-1/4 for one. A considerable part of this was dressed with Patagonian guano, and was much inferior to the other portion. A lot on which 15 bushels was sowed, and dressed with Peruvian guano, was threshed separately, and yielded 301 bushels, or over 20 for one. The whole cost of the farm was $1520, and I have good reason to expect with a favorable season from the crop now sowed and dressed with guano, a bushel of wheat for every dollar of the prime cost of the farm. Many other instances of profit from the use of guano, equally striking have occurred among my neighbors and friends, but I confine myself to those stated, because having come under my immediate observation, I can vouch for their entire accuracy. It has been frequently objected to the use of guano, that it is not permanent. It would be unreasonable to expect great permanent improvement from a manure so active, and which yielded go large a profit on the first crop. Yet I have seen some striking evidences of its permanency in heavy crops of clover, succeeding wheat, and in the increase of the crop of wheat on a second application. As an instance, I may mention that two years ago I sowed upon a single detached acre of "forest land," one bushel of wheat and dressed it with a barrel of African guano, costing $4, and the yield was seventeen bushels. Last fall the same land, after remaining one year in clover, was again sowed with one bushel of wheat and dressed with 140 lbs. of Peruvian guano, costing $3, and the product was 22 bushels. Yet I would advise no one to rely upon guano exclusively. Its analysis shows that it contains salts of ammonia, alkaline phosphates and the other mineral elements necessary to produce the grain of wheat, but is deficient in most of the elements of the straw and roots of the plants. Hence, (says Liebig) 'a rational agriculturist, in using guano, cannot dispense with stable dung.' We should, therefore, be careful not to exhaust the soil of organic manures, but by retaining the straw of the wheat, and occasionally a crop of clover, which plant contains a large percentage of the alkaline carbonates, which are entirely wanting in Guano, furnish all the elements necessary to the entire wheat plant. In this view of the subject, and for many other reasons that I cannot stop to enumerate, there cannot be, when guano is extensively used, a more judicious rotation than the Pamunky five field system, in which clover occupies a prominent place. I have now enumerated some of the most prominent means by which you may "keep your land rich." I would not discourage the use of others. Science is daily making discoveries in the art of enriching the earth, and we should discard nothing, without a trial, which promises to be useful; always bearing in mind that the wisest economy is entirely consistent with the most liberal expenditure, in the purchase of manures, provided we take care, by judicious experiments and observation, to ascertain their efficacy, and that we get back our capital, with an actual _net_ profit _in cash_, on all our investments. This latter caution is indispensable, in our country, where new lands are so abundant and cheap, that highly improved farms can never be rated in the market at their true value."