IX. SUCCESSION OF CROPS (cont.)
Experiments at Rothamstead and Lois Weadon
Some curious information has been obtained regarding the effect of growing successive crops of one kind of plant on the same field, from two examples of it that attracted much attention,. We refer to the experiments of Mr. Lawes at Rothamstead, and of the Rev. Mr. Smith at Lois Weedon. It is well known that Mr. Lawes for a number of years devoted a considerable extent of land to the presecution of a series of interesting experiments, one filed being allotted to experiments with wheat, another to turnips, and another to beans. One acre in the wheat-field bore upwards of twenty successive crops of wheat without any manure whatever. The land was annually scarified and thoroughly cleaned as soon as the crops was removed; it was then ploughed and again drilled with wheat, which was duly hoed in spring. Now, with occasional variation, due to the character of particular seasons, Mr. Lawes found that the average annual produce of his acre was 16 bushels of grain and 16 cwt. of straw, below which he failed to reduce it by these successive crops. His soil was a strong clay loan, resting at a depth of five or six feet upon chalk. In the case of turnips, he found that, when treated in the same way, they cease after a few years to grow larger than radishes, nor could be , by the application of any amount of variety of manure which he tried, obtain a second successive o variety of manure which he tired, obtain a second successive crop equal to the first. With the wheat, on the contrary, the addition of four cwt., of Peruvian guano at once doubled the produce. Mr. Smiths experiments, as is well known, were a revival of Jethro Tulls system of growing wheat continually on the same field, by a plan of alternate strips of wheat and bare fallow, made to change places annually. He improved in so far upon Tulls practice, in as much as he thoroughly drained his land, and his fallow spaces were deeply trenched every autumn, as we as ploughed and hoed during the growing season. The result was than his land thus treated yielded an average annual produce of 34 bushels per acre for eleven or twelve successive crops. Now, it is not our intention to offer any opinion on this as a system of wheat growing. We refer to it along with Mr. Lawess, for the purpose of showing that , notwithstanding the prevalent opinion that grain-crops exhaust the fertility of soils more rapidly than green, this is true only in a very restricted sense. Green crops judiciously interposed do undoubtedly serve a most important purpose in the means which they furnish for maintaining the fertility of a farm; but it is worthy of note, that whereas, by the addition of suitable manure, thorough tillage, and diligent removal of weeds, clay soil, at least will stand an indefinite succession of grain crops, the same means popular green crops. Our personal experience quite accords with this; for we suppose it will be admitted that the corn crops of the country are at the present day superior, both in quality and quantity, to those of any preceding period; whereas potatoes, turnips, and clover, which we have so long regarded as our sheet-anchor, have become increasing precarious, and threaten to fail us together. We refer these facts for the consideration of those who out-and-out condemn the practice of sowing two white crops in immediate succession. In stating this opinion, we must however, guard against misapprehension. Unless the land is highly manured and kept thoroughly clean, we are just as much opposed to the practice as any one can be; buy when mischief is done by it, we believe that it is due rather to the presence of weeds than to the second grain-crops. Neither do we plead for the absolute removal of restrictive clauses from farm leases. Human nature being what it is, men who do not see it go be for their own advantage to farm well, will, through ignorance or greed, impoverish their land unless they are restrained. Clauses as to cropping should, however, be prohibitory rather than prescriptive have reference rather to what is removed from the farm than to what is grown upon it --- and they should be contingent upon the other practices of the tenant. So long as he continues, by ample manuring and careful tillage, to maintain the fertility and general good condition of the farm rented by him, it can be no advantage to his landlord to hinder him from cropping it at his own discretion. It will be seen from these remarks, that we attach more importance to those general principles which should regulate the succession of crops, than to the laying down of formula to meet supposed cases. The man who cultivated by mere routine is unprepared for emergencies, and is sure to lag in the race of improvements; while he who studies principles is still guided by them, while altering his practice to suit changing circumstances.
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