Chapter II: Part 2

[13] The nutritive ratio is the ratio which exists between the digestible crude protein and the combined digestible carbohydrates and fat.

Table IV shows that the percentage composition of both green and cured sweet clover compares favorably with that of alfalfa and red clover.

Perhaps the most interesting point shown in this table is that the fiber content of white sweet clover, whether green or cured into hay, is no greater than that of alfalfa. It is understood, however, that the plants collected for these analyses were taken when they were at the proper stage for curing into hay. Table IV also shows that the digestible nutrients of sweet clover when fed to sheep compare favorably with alfalfa. It was stated that the sweet-clover hay used for this experiment was stemmy and that it had not been cut until it had become woody. The pea hay had passed the best stage for cutting when it was harvested, while the alfalfa hay was in excellent condition.

In a feeding experiment with sheep conducted by two students at the Iowa State College it was found that the protein digested in sweet-clover feed alone was 69 per cent and that the addition of corn to the hay ration increased the digestibility of sweet clover to 82 per cent. Alfalfa and red clover showed similar increases of the digestibility of the protein content when corn was added to the ration. The percentage of digestibility figured for the protein in the corn was the average of a number of digestion experiments. The probability is that the digestibility of the corn was also increased by the presence of the hay in the ration, so that not all the increase in the digestibility should be credited to the hay constituents of the different rations.

FEEDING EXPERIMENTS WITH SWEET CLOVER.

Few agricultural experiment stations have carried on definite feeding experiments to determine the value of sweet clover compared with other feeds.

The South Dakota Agricultural Experiment Station reported an experiment in which lambs were fed on sweet-clover hay in comparison with alfalfa, pea-vine, and prairie hay. In this experiment the lambs made a better gain at a less cost when fed sweet-clover hay than when fed pea-vine hay, but not as large a gain as when fed alfalfa hay. The results of this experiment are shown in Table V.

Table V.--Feeding experiment with lambs in South Dakota, showing the comparative value of different kinds of hay as roughage.

[Grain ration consists of oats and corn in all cases; roughage varies.]

--------------+-------+--------+----------------+---------------+-------
| | | Average weight.|Required for 1 |
| | | |pound of gain. |Average
| | +--------+-------+-------+-------+ daily
| Number|Duration| | | | | gain
Roughage fed.| of |of test.|At be- |At end.|Grain. | Hay. | per
| lambs.| |ginning.| | | | head.
--------------+-------+--------+--------+-------+-------+-------+-------
| | | | | | |
| | Days. |Pounds. |Pounds.|Pounds.|Pounds.|Pounds.
Prairie hay | 16 | 67 | 83.6 | 107.9 | 5.09 | 2.35 | 0.36
Pea-vine hay | 10 | 67 | 83.6 | 107.3 | 5.40 | 3.15 | .35
Alfalfa hay | 5 | 67 | 81.4 | 119.4 | 3.36 | 3.02 | .56
Sweet-clover | 10 | 67 | 84.7 | 113.6 | 4.42 | 3.19 | .43
hay | | | | | | |
--------------+-------+--------+--------+-------+-------+-------+-------

The Wyoming Agricultural Experiment Station also performed an, interesting experiment with lambs. A number of pens of 10 to 40 lambs each were fed different mixtures of feeds for 14 weeks. Those receiving sweet-clover hay, corn, and a small amount of oil meal made an average gain of 30.7 pounds per head, as compared with 20.3 pounds for those receiving native-grass hay, oats, and oil meal. Those receiving alfalfa hay and corn made a gain of more than 34 pounds per head. The results obtained with four pens of lambs in this experiment are given in Table VI.

Table VI.--Results of feeding tests of lambs in Wyoming covering 14 weeks.

-------------+------+-------+-----------------------------------------------
| | | Required for 100 pounds of gain.
| | +-------+-------+-------+-------+-------+-------
| |Average|Sweet- | | | | |
|Number| gain |clover |Native |Alfalfa| Corn. | Oats. | Oil
Ration. | of | per | hay. | hay. | hay. | | | meal.
|lambs.| head. | | | | | |
-------------+------+-------+-------+-------+-------+-------+-------+-------
Sweet-clover | |Pounds.|Pounds.|Pounds.|Pounds.|Pounds.|Pounds.|Pounds.
hay, corn, | | | | | | | |
and oil meal| | | | | | | |
(old process)| 10 | 30.7 | 637.5 | ..... | ..... | 293.2 | ..... | 20.5
| | | | | | | |
Native-grass | | | | | | | |
hay, oats, | | | | | | | |
and oil meal| | | | | | | |
(old process)| 40 | 20.3 | ..... | 606.7 | ..... | ..... | 460.5 | 25.0
| | | | | | | |
Alfalfa hay | | | | | | | |
and corn | 10 | 34.4 | ..... | ..... | 557.5 | 261.6 | ..... | .....
| | | | | | | |
Do | 40 | 34.3 | ..... | ..... | 557.3 | 286.5 | ..... | .....
| | | | | | | |
-------------+------+-------+-------+-------+-------+-------+-------+-------

The sweet-clover hay used in this experiment was described as stemmy and more than a year old; yet it was eaten up clean by the lambs.

The South Dakota Agricultural Experiment Station conducted an experiment in which steers were fed corn silage and various kinds of hay, including sweet clover. The steers which were fed corn silage and sweet-clover hay made an average daily gain of 2.45 pounds, at a cost of $4.34 per hundred pounds of gain, whereas the steers which were fed corn silage and red-clover hay made an average daily gain of 2.29 pounds, at a cost of $4.55 per hundred. The steers that were fed corn silage and alfalfa hay made an average daily gain of 2.49 pounds, at a cost of $4.30 per hundred. In computing the cost of the gains, corn silage was valued at $3 per ton, alfalfa, red-clover, and sweet-clover hay at $10 per ton, and prairie hay at $6 per ton. The results of this experiment, as given in Table VII, show that sweet-clover hay is practically equal to red-clover and alfalfa and greatly superior to prairie hay for roughage for steers.

Table VII.--Feeding experiments with steers in South Dakota, showing the value of sweet-clover hay as compared with some other kinds of hay.

[Corn silage fed in all cases; kind of hay varies.]

------------+-------+--------+----------------+-------+---------------+------
| | |Average weight. | |Feed per pound | Cost
| | +--------+-------+ | of gain. | per
|Number | | At | |Average+-------+-------+ 100
| of |Duration| begin- | At | daily | | |pounds
Roughage. |steers.|of test.| ning. | end. | gain. |Silage.| Hay. | of
| | | | | | | | gain.
------------+-------+--------+--------+-------+-------+-------+-------+------
| | Days. | Pounds.|Pounds.|Pounds.|Pounds.|Pounds.|
Red-clover | | | | | | | |
hay | 4 | 91 | 775 | 983 | 2.29 | 25 | 1.5 | $4.55
| | | | | | | |
Sweet- | | | | | | | |
clover hay| 4 | 91 | 774 | 997 | 2.45 | 23 | 1.5 | 4.34
| | | | | | | |
Alfalfa | 4 | 91 | 775 | 1,005 | 2.49 | 23 | 1.6 | 4.30
| | | | | | | |
Prairie | 4 | 91 | 769 | 951 | 2.01 | 29 | 1.5 | 4.79
hay | | | | | | | |
------------+-------+--------+--------+-------+-------+-------+-------+------

The results of these various experiments are being duplicated every year by many feeders. Each year in the Middle West and Northwest many cattle that bring high prices are being fed with no other roughage than sweet-clover hay. Steers which have been pastured entirely on sweet clover have brought in the Chicago market $1 per hundredweight more than ordinary grass-pastured stock marketed from the same locality and at the same time.

Excellent results were obtained in Lee County, Ill., from feeding steers sweet-clover silage made from plants which had matured a seed crop. For this experiment 91 head of steers 2 and 3 years old, averaging 1,008 pounds per head, were purchased at the Kansas City stock yards on November 16, 1915, at a cost of $6.30 per hundred. These steers were shipped to a farm at Steward and immediately turned on 120 acres of cornstalks. They were fed nothing in addition to the cornstalks until January 14, 1916, when they were put into the feed lot. While they were not weighed when turned into the feed lot, the owner of the steers stated that in his estimation they had gained but little, if any. During the 60 days these steers were in the feed lot they were fed 25 bushels of snapped corn twice a day and as much sweet-clover silage as they would eat. These animals had access to sweet-clover straw during the first part of the feeding period, but after this was consumed they had only oat straw as roughage. At the end of the feeding period they were sold on the Chicago market at the average price of $8.25 per hundred, netting approximately $30 per head. The average weight of these steers in the Chicago yards was 1,177 pounds, 169 pounds more than when purchased in Kansas City.

A most remarkable feature of this experiment is the fact that the steers were fed almost entirely material which would have been considered of little value by the average farmer. The corn which was fed tested 44 per cent moisture at the Rochelle, Ill., elevator, and 20 cents per bushel was the best price offered for it.

Presumably on account of wet weather during the fall of 1915, the sweet-clover seed crop was a failure in that section; in fact, the crop had been cut for seed and part had been thrashed before it was decided that the seed yield was not sufficient to pay for the thrashing. The remainder of the crop was then run into the silo and fed to the steers. The leaves fall and the stems of this plant become hard and woody as the seed matures. The crop therefore would have been worthless for feed had it not been placed in the silo. As a rule, stock readily eat sweet-clover straw when the stems are broken and crushed by the hulling machines. The sweet-clover straw which was used as roughage during the first part of the feeding period was from that part of the seed crop which had been thrashed.

An interesting feeding experiment was conducted on a farm at Rochelle, Ill. On September 7, 1913, 29 head of 2-year-old steers, averaging 836 pounds, were turned on 40 acres of sweet clover which had been seeded that spring with barley. These animals were pastured on the sweet clover until November 1 without additional feed. During this time they made exceptionally large gains. From November 1 to December 11, 28 head of these steers had access to an 80-acre field of cornstalks. On December 11 they were put into the feed lot. During the time these steers were on the cornstalks they barely held their gain, but during the first 30 days they were in the feed lot they made an average daily gain of almost 3 pounds. In this period they received 215 bushels of corn-and-cob meal and 16-3/4 tons of silage made from the first-year growth of sweet clover. During the next 30 days they received 388 bushels of corn-and-cob meal and much less sweet-clover, silage. During this time they made an average daily gain of 2 pounds. When the corn-and-cob meal ration was increased the steers ate less silage. These cattle dressed 55-1/8 per cent at a Chicago packing house.

SWEET CLOVER AS A SOIL-IMPROVING CROP.

Unlike many legumes, sweet clover will make a good growth on soils too depleted in humus for profitable crop production. In addition to its ability to grow and to produce a considerable quantity of forage on such soils, it will add much humus to them. The extensive root systems do much toward breaking up the subsoil, thereby providing better aeration and drainage. The effect of the large, deep roots in opening up the subsoil and providing better drainage is often very noticeable in the spring, as the land upon which sweet clover has grown for several years will be in a condition to plow earlier than the adjacent fields where it has not been grown. The roots are often one-eighth of an inch in diameter at a depth of 3 feet, and they decay in five to eight weeks after the plants die. (Figs. 12 and 13.) The holes made by the roots are left partly filled with a fibrous substance which permits rapid drainage. Sandy soils are benefited materially by the addition of humus and nitrogen, while hardpan often is broken up so completely that alfalfa or other crops will readily grow on the land. The roots add much organic matter to the layers of soil below the usual depth of plowing, while those in the surface soil, together with the stubble and stems, when the crop is plowed under, add more humus than possibly any other legume which may be grown in short rotations. Not only does this crop add organic matter to the soil, but in common with other legumes it has the power of fixing atmospheric nitrogen by means of the nitrogen-gathering bacteria in the nodules on the roots.

The ability of sweet clover to reclaim abandoned, run-down land has been demonstrated in northern Kentucky and in Alabama. In these regions many farms were so depleted in nitrogen and humus by continuous cropping with nonleguminous crops that profitable yields could be obtained no longer, Through the use of this crop many of these farms have been brought back to a fair state of fertility. Tests at the Alabama Agricultural Experiment Station show that the increased yield of corn following sweet clover which had occupied the land for two years was 6-3/4 bushels per acre. The cotton grown on the land the second year showed an increase of 56 pounds per acre. The combined value of the increased yields of corn and cotton for the two years was estimated at $9.75. The total yield of hay for the two preceding years was 6.8 tons per acre. In another experiment at this station cotton was planted on land that had grown sweet clover the two previous years and on land that had received an application of 18 tons of stable manure per acre. The sweet-clover plat produced 280 pounds of seed cotton the first year and 120 pounds of seed cotton the second year more than the plat which received the heavy application of manure.

Land on which sweet clover had been grown for four years at the Ohio Agricultural Experiment Station yielded 26.9 bushels of wheat per acre as compared with 18.6 bushels on the check plat. Sweet clover was seeded at the Tennessee Agricultural Experiment Station in the spring of 1912. One cutting of hay was removed that year and the following spring the field was plowed and planted to corn. The corn yielded 58.8 bushels per acre as compared with 41.1 bushels per acre for an adjoining plat where rye was turned under. A number of tests have been conducted in southeastern Kansas which show clearly the value of sweet clover as a soil-improving crop for that section. The yield of wheat has been increased as much as 7 bushels per acre and that of corn as much as 22 bushels per acre by plowing under the second-year growth of clover.

Annual yellow sweet clover is rapidly gaining in favor as a green-manure crop for orchards in the Southwest. In Arizona two plats seeded in October and plowed under in April yielded, respectively, 16 and 17 tons of green matter to the acre. At the Arizona Agricultural Experiment Station annual yellow sweet clover, lupines, and alfalfa were tested as green-manure crops for orchards. In this experiment the sweet clover clearly showed its superiority to lupines or alfalfa for this purpose, as it yielded from 21 to 26 tons of green matter per acre, whereas the highest yield for the lupines was 10 tons and for the alfalfa 15 tons per acre.

The use of annual sweet clover as a green-manure crop in southern California has increased very rapidly in recent years, and this increased use apparently has been justified by the results obtained with it. One of the most interesting green-manure tests thus far noted was conducted at the California Citrus Experiment Station. In this experiment nine legume plats and eight nonlegume plats alternated with each other. The 4-year average weight of green matter produced on the sweet-clover plat was 14-3/4 tons per acre, whereas the 5-year average weight of green matter produced by common vetch and Canada field peas was 12 tons and 9 tons, respectively, per acre. On one series of these plats corn was planted in rotation with the clover. The average yield of shelled corn for four years was 46 bushels to the acre on the sweet-clover plat, as compared with 35 bushels to the acre on the common-vetch plat and 40 bushels per acre on the field-pea plat. One barley plat receiving each year an application of 1,080 pounds of nitrate of soda gave an average yield of 41 bushels per acre. The 2-year average yield of potatoes following sweet clover was 252 bushels per acre, as compared with 171 bushels following common vetch and 234 bushels following field peas. Sweet clover has proved to be an excellent plant to grow in rotation with sugar beets, as the 2-year average for the beets following it was 19.8 tons per acre, as compared with 15.3 tons following common vetch, and 17.6 tons following field peas.

Annual yellow sweet clover makes a profitable growth only in the South and Southwest and therefore should not be planted in any other section of the country.

In those sections of the United States where the soils are low in humus it is to be strongly recommended that sweet clover be grown for green manure. This method is being practiced in some sections of the country with excellent results.

It should be remembered that sweet clover will not make a satisfactory growth on acid soils and that it is very essential to provide inoculation if the soil is not inoculated already.

SWEET CLOVER IN ROTATIONS.

As sweet clover is a biennial plant, it lends itself readily to short rotations. It may be seeded in the spring on winter grain or with spring grain, the same as red clover. It will produce at least as much pasturage the following fall as red clover, and in some parts of the country a cutting of hay may be obtained after the grain harvest. The following year the plants will produce two cuttings of hay or one cutting of hay and a seed crop. In some sections of the United States this plant is replacing red clover in rotations, as it will succeed on poorer soils than red clover and will add much more humus to the soil. It will withstand drought better than either red clover or alfalfa, and on this account its use in rotations may be extended into drier sections. As a rule the beneficial effect of sweet clover on the subsequent crops is more marked than that of other legumes. This is especially true with corn, and whenever possible corn should follow sweet clover in rotations. Root crops also are benefited by its use in rotations, as the large deep roots of sweet clover open up the soil.

SWEET CLOVER AS A HONEY PLANT.

A number of the leading honey plants fail to secrete nectar in part of the territory in which they are found, but white sweet clover ranks as a valuable source of nectar wherever found in sufficient quantity in the United States. The period of nectar secretion usually follows that of white and alsike clovers in the Northern States, and consequently comes at a time when the colonies are strong enough to get the full benefit of the secretion. The honey from white sweet clover is light in color, with a slight green tint, the flavor being mild and suggestive of vanilla. The characteristic flavor and color of the honey seem to be less marked during a rapid secretion of nectar, In the irrigated portions of the West honey from white sweet clover is often mixed with that from alfalfa.

Beekeepers have long recognized the value of sweet clover as a source of nectar, and for years tons of seed have been sold annually by dealers in beekeepers' supplies. It has never been found profitable to cultivate any plant solely for nectar, and those beekeepers who were primarily interested in the plant for bee forage have scattered the seed chiefly in waste places and along railroad embankments and roadsides. A number of beekeepers who were also engaged in general farming have for years utilized the plant for forage, and they were among the earliest to grow the plant for seed, so as to be able to supply their fellow beekeepers. Sweet clover to-day is almost the only plant which beekeepers seek to increase in waste lands in their localities.

The yield of nectar from sweet clover is heavy, and a number of beekeepers now market this honey in carload lots. Sweet clover is utilized for honey especially in Kentucky, in Iowa, and in Colorado and adjacent States. In Alabama and Mississippi a number of beekeepers are harvesting large crops chiefly from this source. The color and flavor make this plant suitable for either comb or extracted honey.

Yellow sweet clover is perhaps as valuable for nectar as white sweet clover, but beekeepers have paid less attention to it. This is probably due to the fact that the blooming period of the yellow species often coincides with that of white and alsike clover, making it less valuable to the beekeeper. In sections where the quantity of white and alsike clover is limited and it is desired to plant sweet clover for bee pasturage, a mixture of the white and yellow species is recommended, as the yellow species will bloom from 10 to 14 days earlier than the white.

Wherever any of the species of sweet clover are cultivated, either for forage or for seed, beekeeping is to be recommended as a valuable source of additional income, and such locations are especially suitable for extensive commercial beekeeping.

* * * * *

Transcriber Note

Minor typos may have been corrected. Illustrations may have been moved to avoid splitting paragraphs. Many of the Tables have labels which are displayed as italics; but due to space limitations in the text-only version, the italicization was ignored.

End of Project Gutenberg's USDA Farmers' Bulletin No. 820, by H. S. Coe