# Farmers of forty centuries/Chapter 09

Madison, Wisconsin: Mrs. F. H. King pages 193-215
IX.
THE UTILIZATION OF WASTE.
One of the most remarkable agricultural practices adopted by any civilized people is the centuries-long and well nigh universal conservation and utilization of all human waste in China, Korea and Japan, turning it to marvelous account in the maintenance of soil fertility and in the production of food. To understand this evolution it must be recognized that mineral fertilizers so extensively employed in modern western agriculture, like the extensive use of mineral coal, had been a physical impossibility to all people alike until within very recent years. With this fact must be associated the very long unbroken life of these nations and the vast numbers their farmers have been compelled to feed.
When we reflect upon the depleted fertility of our own older farm lands, comparatively few of which have seen a century's service, and upon the enormous quantity of mineral fertilizers which are being applied annually to them in order to secure paying yields, it becomes evident that the time is here when profound consideration should be given to the practices the Mongolian race has maintained through many centuries, which permit it to be said of China that one-sixth of an acre of good land is ample for the maintenance of one person, and which are feeding an average of three people per acre of farm land in the three southernmost of the four main islands of Japan.
From the analyses of mixed human excreta made by Wolff in Europe and by Kellner in Japan it appears that, ​as an average, these carry in every 2000 pounds 12.7 pounds of nitrogen, 4 pounds of potassium and 1.7 pounds of phosphorus. On this basis and that of Carpenter, who estimates the average amount of excreta per day for the adult at 40 ounces, the average annual production per million of adult population is 5,794,300 pounds of nitrogen; 1,825,000 pounds of potassium, and 775,600 pounds of phosphorus carried in 456,250 tons of excreta. The figures which Hall cites in Fertilizers and Manures, would make these amounts 7,940,000 pounds of nitrogen; 3,070,500 pounds of potassium, and 1,965,600 pounds of phosphorus, but the figures he takes and calls high averages give 12,000,000 of nitrogen; 4,151,000 pounds of potassium, and 3,057,600 pounds of phosphorus.
Fig. 106.—A flotilla of manure boats on Soochow creek, collecting human wastes in the city of Shanghai, China, for removal to cultivated fields.
​ In 1908 the International Concessions of the city of Shanghai sold to one Chinese contractor for $31,000, gold, the privilege of collecting 78,000 tons of human waste, under stipulated regulations, and of removing it to the country for sale to farmers. The flotilla of boats seen in Fig. 106 is one of several engaged daily in Shanghai throughout the year in this service.
Dr. Kawaguchi, of the National Department of Agriculture and Commerce, taking his data from their records, informed us that the human manure saved and applied to the fields of Japan in 1908 amounted to 23,850,295 tons, which is an average of 1.75 tons per acre of their 21,321 square miles of cultivated land in their four main islands.
On the basis of the data of Wolff, Kellner and Carpenter, or of Hall, the people of the United States and of Europe are pouring into the sea, lakes or rivers and into the underground waters from 5,794,300 to 12,000,000 pounds of nitrogen; 1,881,900 to 4,151,000 pounds of potassium, and 777,200 to 3,057,600 pounds of phosphorus per million of adult population annually, and this waste we esteem one of the great achievements of our civilization. In the Far East, for more than thirty centuries, these enormous wastes have been religiously saved and today the four hundred million of adult population send back to their fields annually 150,000 tons of phosphorus; 376,000
​tons of potassium, and 1,158,000 tons of nitrogen comprised in a gross weight exceeding 182 million tons, gathered from every home, from the country villages and from the great cities like Hankow-Wuchang-Hanyang with its 1,770,000 people swarming on a land area delimited by a radius of four miles.
Fig. 107.—Map of country surrounding Shanghai, China, showing a few of the many canals on which the waste of the city is conveyed by boat to the farms.
Man is the most extravagant accelerator of waste the world has ever endured. His withering blight has fallen upon every living thing within his reach, himself not
​excepted; and his besom of destruction in the uncontrolled hands of a generation has swept into the sea soil fertility which only centuries of life could accumulate, and yet this fertility is the substratum of all that is living. It must be recognized that the phosphate deposits which we are beginning to return to our fields are but measures of fertility lost from older soils, and indices of processes still in progress. The rivers of North America are estimated to carry to the sea more than 500 tons of phosphorus with each cubic mile of water. To such loss modern civilization is adding that of hydraulic sewage disposal through which the waste of five hundred millions of people might be more than 194,300 tons of phosphorus annually, which could not be replaced by 1,295,000 tons of rock phosphate, 75 per cent pure. The Mongolian races, with
​a population now approaching the figure named; occupying an area little more than one-half that of the United States, tilling less than 800,000 square miles of land, and much of this during twenty, thirty or perhaps forty centuries; unable to avail themselves of mineral fertilizers, could not survive and tolerate such waste. Compelled to solve the problem of avoiding such wastes, and exercising the faculty which is characteristic of the race, they “cast down their buckets where they were”, as
A ship lost at sea for many days suddenly sighted a friendly vessel. From the mast of the unfortunate vessel was seen a signal, “Water, water; we die of thirst!” The answer from the friendly vessel at once came back, “Cast down your bucket where you are.” A second time the signal, “Water, water; Send us water!” ran up from the distressed vessel, and was answered, “Cast down your bucket where you are.” And a third and fourth signal for water was answered, “Cast down your bucket where you are.” The captain of the distressed vessel, at last heeding the injunction, cast down his bucket, and it came up full of fresh sparkling water from the mouth of the Amazon river.
Not even in great cities like Canton, built in the meshes of tideswept rivers and canals; like Hankow on the banks of one of the largest rivers in the world; nor yet in modern Shanghai, Yokohama or Tokyo, is such waste permitted. To them such a practice has meant race suicide and they have resisted the temptation so long that it has ceased to exist.
Fig. 108.—Type of conveyance extensively used in Japan for the removal of city and village waste. Such carts are even more frequently drawn by men than by cattle or horses, and tightly covered casks supported on saddles are borne on the backs of both cattle and horses, while men carry pails long distances on their shoulders, using the carrying pole.
​ Dr. Arthur Stanley, Health officer of the city of Shanghai, in his annual report for 1899. considering this subject as a municipal problem, wrote:
“Regarding the bearing on the sanitation of Shanghai of the relationship between Eastern and Western hygiene, it may be said, that if prolonged national life is indicative of sound sanitation, the Chinese are a race worthy of study by all who concern themselves with Public Health. Even without the returns of a Registrar-General it is evident that in China the birth rate must very considerably exceed the death rate, and have done so in an average way during the three or four thousand years that the Chinese nation has existed. Chinese hygiene, when compared with medieval English, appears to advantage. The main problem ​of sanitation is to cleanse the dwelling day by day, and if this can be done at a profit so much the better. While the ultracivilized Western elaborates destructors for burning garbage at a financial loss and turns sewage into the sea, the Chinaman uses both for manure. He wastes nothing while the sacred duty of agriculture is uppermost in his mind. And in reality recent bacterial work has shown that faecal matter and house refuse are best destroyed by returning them to clean soil, where natural purification takes place. The question of destroying garbage can, I think, under present conditions in Shanghai, be answered in a decided negative. While to adopt the water-carriage system for sewage and turn it into the river, whence the water supply is derived, would be an act of sanitary suicide. It is best, therefore, to make use of what is good in Chinese hygiene, which demands respect, being, as it is, the product of an evolution extending from more than a thousand years before the Christian era.”
Fig. 109.—Receptacles for human waste.
The storage of such waste in China is largely in stoneware receptacles such as are seen in Fig. 109, which are hard-burned, glazed terra-cotta urns, having capacities ranging from 500 to 1000 pounds. Japan more often uses sheltered cement-lined pits such as are seen in Fig. 110.
In the three countries the carrying to the fields is ​oftenest in some form of pail, as seen in Fig. 111, a pair of which are borne swinging from the carrying pole. In applying the liquid to the field or garden the long handle dipper is used, seen in Fig. 112.
Fig. 110.—Japanese sheltered cement-lined storage pits for liquid manure.
We are beginning to husband with some economy the waste from our domestic animals but in this we do not approach that of China, Korea and Japan. People in China regularly search for and collect droppings along the country and caravan roads. Repeatedly, when walking through city streets, we observed such materials quickly and apparently eagerly gathered, to be carefully stored under conditions which ensure small loss from either leaching or unfavorable fermentation. In some mulberry orchards visited the earth had been carefully hoed back about the trunks of trees to a depth of three or four inches from a circle having a diameter of six to eight feet, and upon these areas were placed the droppings of silkworms, the moulted skins, together with the bits of leaves and stem left after feeding. Some disposition of such waste must be made. They return at once to the orchard all ​but the silk produced from the leaves; unnecessary loss is thus avoided and the material enters at once the service of forcing the next crop of leaves.
Fig. 111.—Six carrying pails such as are used in distributing liquid manure to the fields.
On the farm of Mrs. Wu, near Kashing, while studying the operation of two irrigation pumps driven by two cows, lifting water to flood her twenty-five acres of rice field preparatory to transplanting, we were surprised to observe that one of the duties of the lad who had charge of the animals was to use a six-quart wooden dipper with a bamboo handle six feet long to collect all excreta, before they fell upon the ground, and transfer them to a receptacle provided for the purpose. There came a flash of resentment that such a task was set for the lad, for we were only beginning to realize to what lengths the practice of economy may go, but there was nothing irksome suggested in the boy's face. He performed the duty as a matter of course and as we thought it through there was no reason why it should have been otherwise. In fact, the only ​right course was being taken. Conditions would have been worse if the collection had not been made. It made possible more rice. Character of substantial quality was building in the lad which meant thrift in the growing man and continued life for the nation.
Fig. 112.—Applying of liquid manure from carrying pails, using the long-handle dipper.
We have adverted to the very small number of flies observed anywhere in the course of our travel, but its significance we did not realize until near the end of our stay. Indeed, for some reason, flies were more in evidence during the first two days on the steamship, out from Yokohama on our return trip to America, than at any time before on our journey. It is to be expected that the eternal vigilance which seizes every waste, once it has become such, putting it in places of usefulness, must contribute much toward the destruction of breeding places, and it may be these nations have been mindful of the wholesomeness of their practice and that many phases of the evolution of their waste disposal system have been ​dictated by and held fast to through a clear conception of sanitary needs.
Fig. 113.—Where the yield is the product of brain, brawn and utilized waste.
​ Much intelligence and the highest skill are exhibited by these old-world farmers in the use of their wastes. In Fig. 113 is one of many examples which might be cited. The man walking down the row with his manure pails swinging from his shoulders informed us on his return that in his household there were twenty to be fed; that from this garden of half an acre of land he usually sold a product bringing in $400, Mexican,—$172, gold. The crop was cucumbers in groups of two rows thirty inches apart and twenty-four inches between the groups. The plants were eight to ten inches apart in the row. He had just marketed the last of a crop of greens which occupied the space between the rows of cucumbers seen under the strong, durable, light and very readily removable trellises. On May 28 the vines were beginning to run, so not a minute had been lost in the change of crop. On the contrary this man had added a month to his growing season by over-lapping his crops, and the trellises enabled him to feed more plants of this type than there was room for vines on the ground. With ingenuity and much labor he had made his half acre for cucumbers equivalent to more than two. He had removed the vines entirely from the ground; had provided a travel space two feet wide, down which he was walking, and he had made it possible to work about the roots of every plant for the purpose of hoeing and feeding. Four acres of cucumbers handled by American field methods would not yield more than this man's one, and he grows besides two other crops the same season. The difference is not so much in activity of muscle as it is in alertness and efficiency of the grey matter of the brain. He sees and treats each plant individually, he loosens the ground so that his liquid manure drops immediately beneath the surface within reach of the active roots. If the rainfall has been scanty and the soil is dry he may use ten of water to two of night soil, not to supply water but to make ​certain sufficiently deep penetration. If the weather is rainy and the soil over wet, the food is applied more concentrated, not to lighten the burden but to avoid waste by leaching and over saturation. While ever crowding growth he never overfeeds. Forethought, after-thought and the mind focussed on the work in hand are characteristic of these people. We do not recall to have seen a man smoking while at work. They enjoy smoking, but prefer to do this also with the attention undivided and thus get more for their money.
On another date earlier in May we were walking in the fields without an interpreter. For half an hour we stood watching an old gardener fitting the soil with his spading hoe in the manner seen in Fig. 26, where the graves of his ancestors occupy a part of the land. Angleworms were extremely numerous, as large around as an ordinary lead pencil and, when not extended, two-thirds as long, decidedly greenish in color. Nearly every stroke of the spade exposed two to five of these worms but so far as we observed, and we watched the man closely, pulverizing the soil, he neither injured nor left uncovered a single worm. While he seemed to make no effort to avoid injuring them or to cover them with earth, and while we could not talk with him, we are convinced that his action was continually guarded against injuring the worms. They certainly were subsoiling his garden deeply and making possible a freer circulation of air far below the surface. Their great abundance proved a high content of organic matter present in the soil and, as the worms ate their way through it, passing the soil through their bodies, the yearly volume of work done by them was very great. In the fields flooded preparatory to fitting them for rice these worms are forced to the surface in enormous numbers and large flocks of ducks are taken to such fields to feed upon them.
In another field a crop of barley was nearing maturity. An adjacent strip of land was to be fitted and planted. The leaning barley heads were in the way. Not one must be lost and every inch of ground must be put to use. The ​grain along the margin, for a breadth of sixteen inches, had been gathered into handfuls and skillfully tied, each with an unpulled barley stem, without breaking the straw, thus permitting even the grains in that head to fill and be gathered with the rest, while the tying set all straws well aslant, out of the way, and permitted the last inch of naked ground to be fitted without injuring the grain.
In still another instance a man was growing Irish potatoes to market when yet small. He had enriched his soil; he would apply water if the rains were not timely and sufficient, and had fed the plants. He had planted in rows only twelve to fourteen inches apart with a hill every eight inches in the row. The vines stood strong, straight, fourteen inches high and as even as a trimmed hedge. The leaves and stems were turgid, the deepest green and as prime and glossy as a prize steer. So close were the plants that there was leaf surface to intercept the sunshine falling on every square inch of the patch. There were no potato beetles and we saw no signs of injury but the gardener was scanning the patch with the eye of a robin. He spied the slightest first drooping of leaves in a stem; went after the difficulty and brought and placed in our hand a cutworm, a young tuber the size of a marble and a stem cut half off, which he was willing to sacrifice because of our evident interest. But the two friends who had met were held apart by the babel of tongues.
Nothing is costing the world more; has made so many enemies, and has so much hindered the forming of friendships as the inability to fully understand; hence the dove that brings world peace must fly on the wings of a common language, and the bright star in the east is world commerce, rising on rapidly developing railway and steamship lines, heralded and directed by electric communication. With world commerce must come mutual confidence and friendship requiring a full understanding and therefore a common tongue. Then world peace will be permanently assured. It is coming inevitably and faster than we think. Once this desired end is seriously sought, the carrying of ​three generations of children through the public schools where the world language is taught together with the mother tongue, and the passing of the parents and grandparents, would effect the change.
The important point regarding these Far East people, to which attention should be directed, is that effective thinking, clear and strong, prevails among the farmers who have fed and are still feeding the dense populations from the products of their limited areas. This is further indicated in the universal and extensive use of plant ashes derived from fuel grown upon cultivated fields and upon the adjacent hill and mountain lands.
We were unable to secure exact data regarding the amount of fuel burned annually in these countties, and of ashes used as fertilizer, but a cord of dry oak wood weighs about 3500 pounds, and the weight of fuel used in the home and in manufactures must exceed that of two cords per household. Japan has an average of 5.563 people per family. If we allow but 1300 pounds of fuel per capita, Japan's consumption would be 31,200,000 tons. In view of the fact that a very large share of the fuel used in these countries is either agricultural plant stems, with an average ash content of 5 per cent, or the twigs and even leaves of trees, as in the case of pine bough fuel, 4.5 per cent of ash may be taken as a fair estimate. On this basis, and with a content of phosphorus equal to .5 per cent, and of potassium equal to 5 per cent, the fuel ash for Japan would amount to 1,404,000 tons annually, carrying 7020 tons of phosphorus and 70,200 tons of potassium, together with more than 400,000 tons of limestone, which is returned annually to less than 21,231 square miles of cultivated land.
In China, with her more than four hundred millions of people, a similar rate of fuel consumption would make the phosphorus and potassium returned to her fields more than eight times the amounts computed for Japan. On the basis of these statements Japan's annual saving of phosphorus from the waste of her fuel would be equivalent to ​more than 46,800 tons of rock phosphate having a purity of 75 per cent, or in the neighborhood of seven pounds per acre. If this amount, even with the potash and limestone added, appears like a trifling addition of fertility it is important for Americans to remember that even if this is so, these people have felt compelled to make the saving.
Fig. 114.—Japanese farmer tramping green herbage for fertilizer into the water and mud between rows of rice.
In the matter of returning soluble potassium to the cultivated fields Japan would be applying with her ashes the equivalent of no less than 156,600 tons of pure potassium sulphate, equal to 23 pounds per acre; while the lime carbonate so applied annually would be some 62 pounds per acre.
In addition to the forest lands, which have long been made to contribute plant food to the cultivated fields through fuel ashes, there are large areas which contribute green manure and compost material. These are chiefly hill lands, aggregating some twenty per cent of the cultivated ​fields, which bear mostly herbaceous growth. Some 2,552,741 acres of these lands may be cut over three times each season, yielding, in 1903, an average of 7980 pounds per acre. The first cutting of this hill herbage is mainly used on the rice fields as green manure, it being tramped into the mud between the rows after the manner seen in Fig. 114.
This man had been with basket and sickle to gather green herbage wherever he could and had brought it to his rice paddy. The day in July was extremely sultry. We came upon him wading in the water half way to his knees, carefully laying the herbage he had gathered between alternate rows of his rice, one handful in a place, with tips overlapping. This done he took the attitude seen in the illustration and, gathering the materials into a compact bunch, pressed it beneath the surface with his foot. The two hands smoothed the soft mud over the grass and righted the disturbed spears of rice in the two adjacent hills. Thus, foot following foot, one bare length ahead, the succeeding bunches of herbage were submerged until the last had been reached, following between alternate rows only a foot apart, there being a hill every nine to ten inches in the row and the hands grasping and being drawn over every one in the paddy.
He was renting the land, paying therefor forty kan of rice per tan, and his usual yield was eighty kan. This is forty-four bushels of sixty pounds per acre. In unfavorable seasons his yield might be less but still his rent would be forty kan per tan unless it was clear that he had done all that could reasonably be expected of him in securing the crop. It is difficult for Americans to understand how it is possible for the will of man, even when spurred by the love of home and family, to hold flesh to tasks like these.
The second and third cuttings of herbage from the genya lands in Japan are used for the preparation of compost applied on the dry-land fields in the fall or in the spring of the following season. Some of these lands are pastured, ​but approximately 10,185,500 tons of green herbage grown and gathered from the hills contributes much of its organic matter and all of its ash to enrich the cultivated fields. Such wild growth areas in Japan are the commons of the near by villages, to which the people are freely admitted for the purpose of cutting the herbage. A fixed time may be set for cutting and a limit placed upon the amount which may be carried away, which is done in the manner seen in Fig. 115. It is well recognized by the people that this constant cutting and removal of growth from the hill lands, with no return, depletes the soils and reduces the amount of green herbage they are able to secure.
Fig. 115.— Father and children returning from genya lands with herbage for use as green manure or for making compost. The daughter carries the tea kettle to supply their safe, sanitary drink.
Through the kindness of Dr. Daikuhara of the Imperial Agricultural Experiment Station at Tokyo we are able to ​give the average composition of the green leaves and young stems of five of the most common wild species of plants cut for green manure in June. In each 1000 pounds the amount of water is 562.18 pounds; of organic matter, 382.68 pounds; of ash, 55.14 pounds; nitrogen, 4.78 pounds; potassium, 2.407 pounds, and phosphorus, .34 pound. On the basis of this composition and an aggregate yield of 10,185,500 tons, there would be annually applied to the cultivated fields 3463 tons of phosphorus and 24,516 tons of potassium derived from the genya lands.
In addition to this the run-off from both the mountain and the genya lands is largely used upon the rice fields, more than sixteen inches of water being applied annually to them in some prefectures. If such waters have the composition of river waters in North America, twelve inches of water applied to the rice fields of the three main islands would contribute no less than 1200 tons of phosphorus and 19,000 tons of potassium annually.
Dr. Kawaguchi, of the National Department of Agriculture and Commerce, informed us that in 1908 Japanese farmers prepared and applied to their fields 22,812,787 tons of compost manufactured from the wastes of cattle, horses, swine and poultry, combined with herbage, straw and other similar wastes and with soil, sod or mud from ditches and canals. The amount of this compost is sufficient to apply 1.78 tons per acre of cultivated land of the southern three main islands.
From data obtained at the Nara Experiment Station, the composition of compost as there prepared shows it to contain, in each 2000 pounds, 550 pounds of organic matter; 15.6 pounds of nitrogen; 8.3 pounds of potassium, and 5.24 pounds of phosphorus. On this basis 22,800,000 tons of compost will carry 59,700 tons of phosphorus and 94,600 tons of potassium. The construction of compost houses is illustrated in Fig. 116, reproduced from a large circular sent to farmers from the Nara Experiment Station, and an exterior of one at the Nara Station is given in Fig. 117.
Fig. 116.—Section of chart issued by the Nara Experiment Station, illustrating construction of compost house; upper section shows elevation; middle portion is a cross section and the lower shows floor plan.
This compost house is designed to serve two and a half acres. Its floor is twelve by eighteen feet, rendered watertight by a mixture of clay, lime and sand. The walls are of earth, one foot thick, and the roof is thatched with straw. Its capacity is sixteen to twenty tons, having a cash value of 60 yen, or $30. In preparing the stack, materials are brought daily and spread over one side of the compost floor until the pile has attained a hight of five feet. After one foot in depth has been laid and firmed, 1.2 inches of soil or mud is spread over the surface and the process repeated until full hight has been attained. Water is added sufficient to keep the whole saturated and ​to maintain the temperature below that of the body. After the compost stacks have been completed they are permitted to stand five weeks in summer, seven weeks in winter, when they are forked over and transferred to the opposite side of the house.
Fig. 117. — Exterior view of compost house at Nara Experiment Station.
If we state in round numbers the total nitrogen, phosphorus and potassium thus far enumerated which Japanese farmers apply or return annually to their twenty or twenty-one thousand square miles of cultivated fields, the case stands 385,214 tons of nitrogen, 91,656 tons of phosphorus and 255,778 tons of potassium. These values are only approximations and do not include the large volume and variety of fertilizers prepared from fish, which have long been used. Neither do they include the very large amount of nitrogen derived directly from the atmosphere through their long, extensive and persistent cultivation of soy beans and other legumes. Indeed, from 1903 to 1906 the average area of paddy field upon which was grown a second crop of green manure in the form of some legume was 6.8 per cent of the total area of such fields aggregating 11,000 square miles. In 1906 over 18 per cent of the upland fields also produced some leguminous crop, ​these fields aggregating between 9,000 and 10,000 square miles.
While the values which have been given above, expressing the sum total of nitrogen, phosphorus and potassium applied annually to the cultivated fields of Japan may be somewhat too high for some of the sources named, there is little doubt that Japanese farmers apply to their fields more of these three plant food elements annually than has been computed. The amounts which have been given are sufficient to provide annually, for each acre of the 21,321 square miles of cultivated land, an application of not less than 56 pounds of nitrogen, 13 pounds of phosphorus and 37 pounds of potassium. Or, if we omit the large northern island of Hokkaido, still new in its agriculture and lacking the intensive practices of the older farm land, the quantities are sufficient for a mean application of 60, 14 and 40 pounds respectively of nitrogen, phosphorus and potassium per acre, and yet the maturing of 1000 pounds of wheat crop, covering grain and straw as water-free substance, removes from the soil but 13.9 pounds of nitrogen, 2.3 pounds of phosphorus and 8.4 pounds of potassium, from which it may be computed that the 60 pounds of nitrogen added is sufficient for a crop yielding 31 bushels of wheat; the phosphorus is sufficient for a crop of 44 bushels, and the potassium for a crop of 35 bushels per acre.
Dr. Hopkins, in his recent valuable work on “Soil Fertility and Permanent Agriculture” gives, on page 154, a table from which we abstract the following data:
APPROXIMATE AMOUNTS OF NITROGEN, PHOSPHORUS AND POTASSIUM REMOVABLE PER ACRE ANNUALLY BY
| | Nitrogen, pounds. | Phosphorus, pounds. | Potassium, pounds. |
| 100 bush. crop of corn | 148 | 23 | 71 |
| 100 bush. crop of oats | 97 | 16 | 68 |
| 50 bush. crop of wheat | 96 | 16 | 58 |
| 25 bush. crop of soy beans | 159 | 21 | 73 |
| 100 bush. crop of rice | 155 | 18 | 95 |
| 3 ton crop of timothy hay | 72 | 9 | 71 |
| 4 ton crop of clover hay | 160 | 20 | 120 |
| 3 ton crop of cow pea hay | 130 | 14 | 98 |
| 8 ton crop of alfalfa hay | 400 | 36 | 192 |
| 7,000 lb. crop of cotton | 168 | 29.4 | 82 |
| 400 bush. crop of potatoes | 84 | 17.3 | 120 |
| 20 ton crop of sugar beets | 100 | 18 | 157 |
| Annually applied in Japan, more than | 60 | 14 | 40 |
of rice, and have increased the crop of potatoes from three hundred bushels to four hundred bushels per acre, because such a yield, like all of those named, is quite practicable under good management and favorable seasons, notwithstanding the fact that much smaller yields are generally attained through lack of sufficient plant food or water. From this table, assuming that a crop of matured grain contains 11 per cent of water and the straw 15 per cent, while potatoes contain 79 per cent and beets 87 per cent, the amounts of the three plant food elements removable annually by 1000 pounds of crop have been calculated and stated in the next table.
APPROXIMATE AMOUNTS OF NITROGEN, PHOSPHORUS AND POTASSIUM REMOVABLE ANNUALLY PER 1,0000 POUNDS OF DRY CROP SUBSTANCE.
| | | Nitrogen, pounds. | Phosphorus, pounds. | Potassium, pounds. |
| | Cereals. |
| Wheat | | 13.873 | 2.312 | 8.382 |
| Oats | | 13.666 | 2.254 | 9.580 |
| Corn | | 13.719 | 2.149 | 6.676 |
| | Legumes. |
| Soy beans | | 30.807 | 4.070 | 14.147 |
| Cow peas | | 25.490 | 2.745 | 19.216 |
| Clover | | 23.529 | 2.941 | 17.647 |
| Alfalfa | | 29.411 | 2.647 | 14.118 |
| | Roots. |
| Beets | | 19.213 | 3.462 | 30.192 |
| Potatoes | | 15.556 | 3.210 | 22.222 |
| | Grass. |
| Timothy | | 14.117 | 1.765 | 13.922 |
| Rice | | 9.949 | 1.129 | 6.089 |
From the amounts of nitrogen, phosphorus and potassium applied annually to the cultivated fields of Japan and from the data in these two tables it may be readily seen that these people are now and probably long have been applying quite as much of these three plant food elements to their fields with each planting as are removed with the crop, and if this is true in Japan it must also be true in China. Moreover there is nothing in American agricultural practice which indicates that we shall not ultimately be compelled to do likewise.