having no clover. Likewise the average yields of potatoes, wheat, and oats for the group of 38 farms having an average of 32.7 per cent of the field-crop area in clover were 17 per cent, 21 per cent, and 33 per cent higher than the yields of these crops for the group having no clover.

RELATION OF SUMMER FALLOW TO CROP YIELDS.

In considering the influence of summer fallow on crop yields, it must be remembered that 40 to 50 years ago the practice of summer fallowing the land once every three or four years was extensively followed in the Willamette Valley on both the clay and silt loam types of soil; that this practice is still generally followed on the clay soil, but has almost disappeared on the silt loam soil. Table XIII shows the comparative yields of potatoes, wheat, oats, and hay on both the clay and silt loam farms with and without summer fallow.

TABLE XIII.-Relation of summer fallow to crop yields on 212 farms in Marion and Polk Counties, Oreg. (1912).

From Table XIII it will be noted that 57 of the 68 clay farms had more or less tillable land lying idle as summer fallow, and that only 17 of the 144 silt-loam farms were still practicing the summer-fallow method. The clay farms having summer fallow had higher crop yields than the clay farms having no summer fallow, the relative crop index of the groups with and without summer fallow being 101 and 90, respectively. On the other hand, the silt loam farms having no summer fallow had higher crop yields, for all crops except wheat, than the few farms practicing summer fallowing. Because wheat follows summer fallow, its yield should be affected by summer fallow more than the yield of any other crop. The crop index of the silt loam farms having no summer fallow was 101, whereas that of the 17 farms with summer fallow was 96.

It appears, therefore, that on the silt loam farms having no summer fallow, cropping systems have been adopted that give higher crop yields than are secured on the 17 farms still practicing summer fallowing. This has been accomplished, it is safe to say, by the introduction of the leguminous crops. It is reasonably certain that

clover and other legumes would do as much for the clay-soil farms; for farmers who have been growing clover for a number of years on the clay soil claim that they are getting increased yields.

BARNYARD MANURE AND DRAINAGE.

There are other ways of increasing crop yields besides those brought out by the survey data, among which may be mentioned the use of barnyard manure and drainage. It is a well-recognized principle in agriculture that crop yields on almost any type of soil may be increased by a more liberal use of barnyard manure. Especially is this method of increasing crop yields applicable where the soil has been receiving little animal or vegetable manure. The farmer who adopts this method must see to it that the live stock kept are high-producing animals. He must also use good judgment in marketing his live stock and live-stock products. If this is not done, he may increase his crop yields without increasing his profits.

Much of the agricultural land of the Willamette Valley is so low and level that it is water-logged during much of the time in winter. There probably is no other way by which crop yields on such land • can be increased as easily as by drainage. In some localities the individual farm can be drained independently. In other localities the land is so level that it will be necessary to organize drainage districts and work cooperatively in order to get an outlet for the water.

RELATION OF SOIL TYPE TO PERCENTAGE FARM INCOME IS OF

CAPITAL.

Table XIV shows the comparative percentages farm income is of capital on the two major types of soil found in the valley. On the 68 clay farms, it will be seen, farm income was 4.35 per cent of the capital invested, as compared with 6.64 per cent on the 144 silt loam farms. That is to say, the silt loam farms were operated 1.52 times as efficiently as the clay farms. The question naturally arises as to the cause of this difference.

TABLE XIV.-Relation of type of soil to percentage farm income is of capital, on 212 farms in Marion and Polk Counties, Oreg. (1912).

From Table XIV it will be observed that the clay farms had 56.5 more acres of improved land and $3,873 more capital to use than had the silt loam farms. Therefore, the difference in the efficiency

of these farms was not due to the lack of capital or usable land on the part of the clay farms. Neither was it due to the difference in the valuation of real estate on the two types of soil, for Table I shows land was worth $89 per acre on the clay farms and $112 on the silt loam farms.

CAUSES OF THE DIFFERENCE IN EFFICIENCY.

(1) An average of 73.6 per cent of the farm area of the silt loam farm, as shown by Table I, was improved land, as compared with 71.2 per cent for the clay farms. Thus the silt loam farms have available a slightly higher percentage of improved land.

(2) The silt loam farms produced clover seed, whereas the clay farms produced none. As shown in Table VIII, clover seed in 1912 was a very profitable crop. This contributed materially to the difference in the efficiency of the farms on the two types of soil.

TABLE XV.-Relation of types of soil to income per productive animal unit and to crop yield on 212 farms in Marion and Polk Counties, Oreg. (1912).

(3) Table XV shows the number of productive animal units per farm, the income per productive animal, and the crop yields on the two types of soil. It will be seen that the clay farms had an average of 13.87 productive animal units per farm, as compared with 13.19 for the silt loam farms; and that the income per productive animal unit was $4 greater on the silt loam farms than on the clay farms. This would give the silt loam farms an income approximately $55 per farm greater than that of the clay farms.

(4) From Table XV it will also be seen that potatoes, wheat, and hay, three of the four leading crops upon which crop index in this table is based, gave higher yields on the clay farms than on the silt loam farms. Oats, on the other hand, gave the highest yield on the silt loam farms. However, the crop index of the clay farms was 96 as compared with 102 for the silt loam farms. The difference in the yield of oats on the two types of soil and the large percentage of the rotation area devoted to that crop (see fig. 1) are the causes of the clay farms having the lower crop index. Hence, the difference in the percentage farm income is of capital on the two types of soil

may be attributed, at least in part, to the low yield and large acreage of the oat crop on the clay farms.

(5) Perhaps the greatest cause of the lower efficiency of the clay farms is the practice of summer fallowing approximately one-fourth of the rotation area each year. During the year 1912, 24.5 per cent of the rotation area on the clay farms lay idle as summer fallow, as compared with 2.7 per cent on the silt loam farms (see fig. 1). The practice of summer fallowing diminishes net receipts in two ways. In the first place, the land being summer fallowed represents idle capital from which there is no return. Secondly, the cultivation of the idle land during the summer-fallow year materially increases the operating expenses. On the clay farms 46.1 per cent of the gross receipts were required for operating expenses as against 37.7 per cent on the silt loam farms. The work of cultivating the summer fallow is very largely responsible for this difference.

STARTING CLOVER ON THE CLAY SOIL.

From what has been said in this discussion it should be evident that the profitableness of farming on the clay soil can be greatly increased by adopting cropping systems or rotations that will do away with the summer-fallow practice, and in which clover and other leguminous crops will have a prominent place. Until very recently a very large percentage of the farmers on the clay soil thought this was not feasible. During the last few years, however, many attempts have been made to grow clover on the clay soil. During the season

of 1916 a detailed study of 53 trials of growing clover was made in order to determine (1) whether clover can be successfully grown on this type of soil and (2) the most practical ways of getting a stand. The success of the 53 trials, which included 1,111 acres, is shown in Table XVI.

TABLE XVI.-Results of seeding clover alone and with different nurse crops on Salem clay soil, Marion County, Oreg.

It will be noted that a good stand was secured on 931 acres of the 1,111 acres seeded. In other words, 83.8 per cent of the area seeded gave satisfactory results. A good stand was secured on 100 per cent. of the area seeded alone late in May or early in June. A good stand

was also secured on 100 per cent of the area seeded with spring barley and spring wheat. While the number of trials with these two crops is too small to draw very reliable conclusions, studies of starting clover elsewhere show that barley is one of the most satisfactory nurse crops.

The results secured by seeding clover in the spring with spring oats, winter oats, and winter wheat are all that should be expected. The two trials of seeding clover in the fall with winter wheat strongly indicate that that method is unsatisfactory.

METHODS.

From a study of Table XVI three practical methods of starting clover on the clay soil are suggested: (1) Sown alone late in May or early in June; (2) sown with spring grain in the early spring; and (3) sown with winter wheat in the early spring.

1. Seeding clover alone.-For seeding clover alone in the late spring the land is plowed quite deep during the winter and kept thoroughly cultivated from early spring until seeding time. About 8 pounds of red-clover seed per acre are sown alone as soon after the 15th of May as weather conditions will permit. The seed is sown broadcast and covered with a harrow or corrugated roller. This is probably the surest method of getting a stand. It should be used only on land that never grew clover before, because the use of the land is practically lost during the year the clover is seeded. Some farmers sow about 5 pounds of rape seed per acre with the clover. The rape makes good sheep, hog, or calf pasture in about six weeks after seeding. 2. Seeding clover with spring grain.-When clover is seeded in the early spring with barley, wheat, or oats the land is plowed during the fall or winter and a good, firm, mellow seed bed prepared in the early spring. Eight pounds of red-clover seed per acre are sown late in February or early in March immediately after the grain. The seed is covered with the harrow or corrugated roller, preferably with the roller, as it packs the soil.

3. Seeding clover in the spring with winter wheat.-When starting clover with winter wheat about 8 to 10 pounds of seed per acre are sown broadcast late in February or early in March. If wheat has made sufficient growth it is an excellent plan to pasture the field off quickly with sheep. The tramping of the sheep covers the clover seed and packs the ground. After removing the sheep, the field is harrowed to loosen the surface. If no sheep are available, the seed is covered with the harrow.

In starting clover by either of the above methods on land that never produced the crop before, the soil should be as free as possible from weeds. For this reason winter wheat grown on land that was well summer fallowed the previous season makes a good nurse crop. Clover requires a firm, compact seed bed. The corrugated roller is