But improvements in agriculture are of two kinds: those which increase the productive powers of the land, and those which enable us to obtain its produce with less labour. They both lead to a fall in the price of raw produce; they both affect rent, but they do not affect it equally. If they did not occasion a fall in the price of raw produce, they would not be improvements; for it is the essential quality of an improvement to diminish the quantity of labour before required to produce a commodity; and this diminution cannot take place without a fall of its price or relative value.
The improvements which increase the productive powers of the land, are such as the more skilful rotation of crops, or the better choice of manure. These improvements absolutely enable us to obtain the same produce from a smaller quantity of land. If, by the introduction of a course of turnips, I can feed my sheep besides raising my corn, the land on which the sheep were fed becomes unnecessary, and the same quantity of raw produce is raised by the employment of a less quantity of land. If I discover a manure which will enable me to make a piece of land produce 20 per cent. more corn, I may withdraw at least a portion of my capital from the most unproductive part of my farm. But, as I have before observed, it is not necessary that land should be thrown out of cultivation, in order to reduce rent: to produce this effect, it is sufficient that successive portions of capital are employed on the same land with different results, and that the portion which gives the least result should be withdrawn. If, by the introduction of the turnip husbandry, or by the use of a more invigorating manure, I can obtain the same produce with less capital, and without disturbing the difference between the productive powers of the successive portions of capital, I shall lower rent; for a different and more productive portion will be that which will form the standard from which every other will be reckoned. If, for example, the successive portions of capital yielded 100, 90, 80, 70; whilst I employed these four portions, my rent would be 60, or the difference between
| 70 and 100 = 30 | whilst the produce would be 340 | 100 |
| 70 and 90 = 20 | 90 | |
| 70 and 80 = 10 | 80 | |
| — | 70 | |
| 60 | —— | |
| 340 |
and while I employed these portions, the rent would remain the same, although the produce of each should have an equal augmentation. If, instead of 100, 90, 80, 70, the produce should be increased to 125, 115, 105, 95, the rent would still be 60, or the difference between
| 95 and 125 = 30 | whilst the produce would be increased to 440 | 125 |
| 95 and 115 = 20 | 115 | |
| 95 and 105 = 10 | 105 | |
| — | 95 | |
| 60 | —— | |
| 440 |
But with such an increase of produce, without an increase of demand, there could be no motive for employing so much capital on the land; one portion would be withdrawn, and consequently the last portion of capital would yield 105 instead of 95, and rent would fall to 30, or the difference between
| 105 and 125 = 20 | whilst the produce would be stilladequate to the wants of the population, for it would be 345 quarters, or | 125 |
| 105 and 115 = 10 | 115 | |
| — | 105 | |
| 30 | —— | |
| 345 |
the demand being only for 340 quarters.—But there are improvements which may lower the relative value of produce without lowering the corn rent, though they will lower the money rent of land. Such improvements do not increase the productive powers of the land, but they enable us to obtain its produce with less labour. They are rather directed to the formation of the capital applied to the land, than to the cultivation of the land itself. Improvements in agricultural implements, such as the plough and the threshing machine, economy in the use of horses employed in husbandry, and a better knowledge of the veterinary art, are of this nature. Less capital, which is the same thing as less labour, will be employed on the land; but to obtain the same produce, less land cannot be cultivated. Whether improvements of this kind, however, affect corn rent, must depend on the question, whether the difference between the produce obtained by the employment of different portions of capital be increased, stationary, or diminished. If four portions of capital, 50, 60, 70, 80, be employed on the land, giving each the same results, and any improvement in the formation of such capital should enable me to withdraw 5 from each, so that they should be 45, 55, 65, and 75, no alteration would take place in the corn rent; but if the improvements were such as to enable me to make the whole saving on the largest portion of capital, that portion which is least productively employed, corn rent would immediately fall, because the difference between the capital most productive and the capital least productive would be diminished; and it is this difference which constitutes rent.
Without multiplying instances, I hope enough has been said to shew, that whatever diminishes the inequality in the produce obtained from successive portions of capital employed on the same or on new land, tends to lower rent; and that whatever increases that inequality, necessarily produces an opposite effect, and tends to raise it.
In speaking of the rent of the landlord, we have rather considered it as the proportion of the whole produce, without any reference to its exchangeable value; but since the same cause, the difficulty of production, raises the exchangeable value of raw produce, and raises also the proportion of raw produce paid to the landlord for rent, it is obvious that the landlord is doubly benefited by difficulty of production. First he obtains a greater share, and secondly the commodity in which he is paid is of greater value.[8]