Burnt earth mixed with decomposed vegetable matter is another highly esteemed manure, and is common in all the agricultural districts. During the summer months all sorts of vegetable rubbish are collected in heaps by the road-sides, and mixed with straw, grass, parings of turf, &c., which are set on fire and burn slowly for several days, until all the rank vegetable matter is decomposed, and the whole reduced to a rich black earth. It is then turned over several times, when it presents the same appearance as the vegetable mould used in gardens in England. This manure is not scattered over the land, but reserved for covering the seeds, and is applied in the following manner. When the seed time arrives, one man makes the holes, another follows and drops in the seeds, and a third puts a handful of this black earth on the top of them. Being principally vegetable matter, it keeps the seeds loose and moist during the period of germination, and afterwards affords them nourishment. This manure is useful mechanically as well as chemically in a stiff soil, like that of the low lands of China, where the seeds are apt to be injured in the process of germination. The young crop thus planted acquires a vigour in its first growth, which enables it to assimilate the matter which forms the strong stiff soil, and to strike its roots firmly into it.
What is commonly known by the name of oil-cake, is broken up and used in the same manner as the vegetable earth, and is also scattered broadcast over the land. The oil-cake is the remains or refuse of the seeds of several different plants, such as the tallow tree, various kinds of beans, and the cabbage formerly mentioned. There is a great demand for this manure in all parts of the country, and it forms a very considerable branch of trade both by sea and land. Bones, shells, old lime, soot, ashes, and all kinds of rubbish, are also eagerly bought up by the farmer for the purpose of manure.
In the Fa-tee gardens near Canton the proprietors have a curious kind of rich mud, which they cut up into small square bits, and sell at a very high price for the growing of plants in pots. This is obtained chiefly from the ponds and lakes in the vicinity, where the Nelumbium speciosum grows. This soil is so much esteemed, that the price for the best kind is 1 dollar for 3 peculs[2], and for the second 1 dollar for 4 peculs. The inferior sort has been frequently sent to England in plant cases from Canton.
For crops in a vigorous growing state no kind of manure is so eagerly sought after as night soil, and every traveller in China has remarked the large cisterns or earthen tubs which are placed in the most conspicuous and convenient situation for the reception of this kind of manure. What would be considered an intolerable nuisance in every civilised town in Europe, is here looked upon by all classes, rich and poor, with the utmost complacency; and I am convinced that nothing would astonish a Chinaman more, than hearing any one complain of the stench which is continually rising from these manure tanks. Almost every Chinese town is placed on the banks of a river or canal, and the water is generally led not only round the walls, thus forming a kind of moat, but also through many parts of the city. Long clumsy boats are placed in different departments of the town, into which the night soil and urine are emptied and conveyed from thence into the country. The fields in the neighbourhood of cities are generally supplied with it by coolies, who go every morning to market loaded with the produce of their firms. Each brings home two buckets of this manure, slung at the ends of his bamboo pole. In England it is generally supposed that the Chinese carry the night soil and urine to these tanks, and leave it there to undergo fermentation, before they apply it to the land. This, however, is not the case; at least, not generally. In the fertile agricultural districts in the north, I have observed that the greater part of this stimulant is used in a fresh state, being of course sufficiently diluted with water before it is applied to the crops. And there can be little doubt that in this the Chinese are perfectly right, as the manure must be much more efficient in this state than when a great portion of its ammonia has passed off into the air. The Chinese, as far as I could learn, have no mode of disinfecting their manure, but they seem to be perfectly aware, that if allowed free access to the air a great loss must result, owing to the gases which are given out and dissipated. Without waiting, then, for fermentation or putrefaction, this manure is at once applied to the growing crops. On the afternoons, or on cloudy days, the labourers are seen carrying water from the nearest pond or canal to the manure tank, for the purpose of diluting its contents. This being done, they fill their buckets, attaching one to each end of their bamboo in the usual way, and carry them off to their destination. When this is reached, each man takes a small wooden ladle having a long bamboo handle, and with this he scatters the liquid over the growing crop. A strong stimulant like this would probably in other circumstances have an injurious effect; but, by using it only when the crops are young and luxuriant, they assimilate its gases, and a most marked effect is produced upon their growth and productiveness. This kind of liquid manure is generally applied to wheat, barley, and all the cabbage tribe, and other garden vegetables; but not to rice, which is always flooded during its growth.
This manure is sometimes used after putrefaction and fermentation have taken place, and even in this state it is very efficient. In the gardens near Canton it is often dried and mixed with the soil taken from the bottom of the Lotus ponds, and used for growing plants in pots, or for enriching any particular tree which may be a favourite in the garden.
Although the land is sometimes allowed to lie idle for some months, yet there is no regular system of fallowing, nor is the rotation of crops much known or practised. Indeed, as regards the low lands, the soil being a kind of stiff, strong clay, capable of yielding many crops of rice in succession, without being in any way burthened or impoverished, no such mode of cultivation is necessary.
[1] Several of our ploughs have been sent out to China, and offered to the native farmers gratis, but they will not use them.
[2] A Chinese pecul is equal to 133¼ lbs.