Chapter XII.a

RELATIONS OF SPECIAL CROPS TO SPECIAL FEATURES OF

CLIMATE AND OTHER INFLUENCES.

The preceding chapter on phenology has given several illustrations of the influence of the date of planting upon the dates of the resulting phases and on the amounts of the harvest for special plants. The experiments at experiment stations now about to be quoted were undertaken with a view to the further direct elucidation of this relation. From such experiments we obtain definite data by which to decide as to the best date for planting and the probable resulting crop both in normal and abnormal seasons. We see to what extent the seed and plant have acquired habits suitable to the prevailing climate, and furthermore, what climatic influences the plants were not able to withstand when the seeds were planted too early or too late. It is, of course, of prime importance in each case to know where the seeds were grown or to what climate they were acclimatized before being planted at the experiment station.

By measuring the weight and nutritious value of a sample of a crop at various stages of development we are able to form tables showing the relation of the mature ultimate harvest to the immature plant, and this relation is found to be sufficiently constant to justify one in predicting the harvest per acre from its condition on any given day several months before harvesting. Examples of this process have already been given and others now follow.

BEETS AND POTATOES.

DATE OF PLANTING.

Briem finds the crops of beets and potatoes that have become acclimatized in Austria-Hungary vary with date of planting, as given in the table following.

66

a A chapter on 'Forests and climate," which was originally intended to precede this chapter, is omitted.

(309)

Durin has shown that the sugar beet loses the sugar in the root by its consumption in forming stalks and leaves as well as seeds. The roots die when all the sugar is used up, from which I infer that the best time for gathering the beets must be at that period of ripeness in which the formation of leaves ceases, and possibly this formation of leaf and loss of sugar can be checked artificially by cutting the young leaves. (Agr. Sci., Vol. IV, p. 326.)

GRASSES.

The changes in the chemical composition of grass and in the nutritious quality of the dried hay have been determined by E. F. Ladd (Agr. Sci., Vol. I, p. 221) by experiments on timothy (Phleum pratense), who concludes as follows:

(1) The amount of water in timothy diminishes rapidly.

(2) There was a large increase in crude fiber in late-cut timothy over that cut at the period of full bloom.

(3) As the grass approached maturity there was a considerable diminution in the percentage of sugar and an increase of the starch. (4) After the period of full bloom the proportion of albuminoids to the other organic constituents diminished.

(8) Finally, from a chemical point of view, it seems preferable to cut timothy for feeding at the period of full bloom, rather than after the seeds have formed. (Agr. Sci., Vol. I, p. 223.)

The effect of climate on the yield and chemical composition of

grasses, especially the pasture grass, has been studied at the Pennsylvania State College Agricultural Experiment Station, by G. L. Holter (Agr. Sci., Vol. III, p. 285), in connection with studies on the yield per acre. Samples of grass were cut every few days during the season (of 1887), but the comparisons with rainfall and temperature showed no definite relation, except, perhaps, that the percentage of ash increased as the temperature diminished. The following table gives the figures showing the average rainfall and temperature from the middle of one period to the middle of the next, and for the average of seven plats of ground:

If we assume that the whole season extended from May 10 to September 29, we may compute the average daily growth, which will be found to be very large at first, but rather uniform from June 13 to September 16, after which it steadily diminishes. The irregularities in the growth from one week to the next have no simple connection with rainfall or temperature, but there is no evidence to show that other climatic elements, such as sunshine and evaporation, would not have thrown some light upon the subject.

Mr. Holter has also experimented on the yield per acre of pasture grass, as measured week by week during the growing season of 1888 and 1889 at the Pennsylvania State College Agricultural Experiment Station. (See Agr. Sci., Vol. V, p. 52.) The plat experimented upon represents an average of the uplands of the Allegheny Mountains. The weather of the season was most favorable for the growth of grass, having a heavy, evenly distributed rainfall. The following table shows the dates of cutting and the average daily growth between these dates, expressed in pounds of dried grass per acre. It will be seen that there was a rapid increase in growth up to May 21, after which there was a steady decline. The daily average for the whole season of one hundred and seventy-eight days

is 32.13 pounds of fresh matter and 9.06 of dry matter. Evidently a pasture that is fairly well stocked with cattle in May and June will be overstocked in August and September.

C, Richardson (Agr. Sci. Vol. I, p. 125) states that the quality of the grain produced in any locality is dependent principally on three conditions the climate, the soil, and the cultivation. Wheat is most susceptible to its environments; thus the Atlantic slope produces a wheat grain of medium size and with less than the average amount of nitrogenous constituents. In this part of the country latitude exerts a minor influence.

In the Central States-Tennessee, Kentucky, Arkansas—the grain is larger and contains more nitrogen.

In the Northwest a grain is harvested smaller than anywhere and richer in nitrogen.

In Colorado, where irrigation is practiced, a large grain is grown which is rich in nitrogen.

On the northwest Pacific slope the grain is large, very starchy, and with less nitrogen than anywhere else.

The above conditions, as at present existing, are probably in a state of transition.

The following table shows the difference in the composition of the crops of standard varieties of wheat in Minnesota and Dakota :

The following table shows the differences for the varieties raised in the respective States:

The effect of climate and soil on wheat is strikingly shown in that a soft plump yellow wheat from Oregon and a small hard red variety from Minnesota, when used as seed in Colorado, in three years' time had lost nearly all their differences, so as to look more like Colorado grain than like their own originals."

A study of 38 varieties grown during seven years on one farm in Colorado shows a progressive change, as in the following table:

These determinations show plainly that the soil and other conditions in 1885 would not produce as good a crop from introduced seed as in 1881, and that the drop in character of the crops as a whole is due as much or more to soil than to season. The seven varieties grown for several years in Colorado which showed no signs of deterioration are on this account worth considering, since they are perhaps the varieties to select for the locality, because they may be more suited to the conditions there existing than any others. Attention is called to the fact that deterioration in quality, as evidenced by diminution of albuminoids, is shown by the loss of weight per bushel. In the present case a drop of 1.2 per cent in albuminoids was accompanied by a loss in weight of 3 pounds per bushel. No other cereal seems to be influenced by its environment in the same way as wheat. Oats are more changed, by climate and soil, in the outward physical appearance and properties of the grain; barley is modified in its

a There is nothing to show how much this may have been due to spread of pollen from one field to the other.-C. A.