FREQUENT CROPPING LATE IN THE SEASON The results of an experiment to determine the effect of frequent croppings to 1 inch above the ground after seed maturity are shown in Table 10. The average yields per plant of Nevada blue grass and violet wheat grass were much lower in the second year than in the first, and considerably lower in the third year than in the second. These excessive declines in yield per plant of violet wheat grass in three years, varying from about 49 to about 62 per cent in the different methods, are in striking contrast with the increases in the yield of this plant in three years shown in Table 7, amounting to 176 per cent when harvested at seed maturity and at the close of the growing season, and 159 per cent when they were harvested only at seed maturity. TABLE 10.-Results of frequent harvesting after seed maturity PLOTS HARVESTED EACH YEAR AT SEED MATURITY, THEN CUT THREE TIMES AT 10-DAY INTERVALS, AND AFTERMATH REMOVED AT END OF SEASON (ONLY FOUR CUTTINGS IN 1923) PLOTS HARVESTED EACH YEAR AT SEED MATURITY, THEN CUT TWICE AT 15-DAY INTERVALS, AND AFTERMATH REMOVED AT END OF SEASON (ONLY THREE CUTTINGS IN 1923) P-16-30. Nevada blue grass.. 15 15 15 158.71 71.92 51.41 10. 581 4.795 3. 427-54.7-67.6 R-16-30. Violet wheat grass... 15 15 15 316. 85 219. 03 162. 34 21. 123 14. 602 10. 823 -30.9 -48.8 PLOTS HARVESTED EACH YEAR AT SEED MATURITY, THEN CUT ONCE 20 DAYS LATER, AND AFTERMATH REMOVED AT END OF SEASON (ONLY TWO CUTTINGS IN 1923) 70.54 3.469-65.5-74.5 7.733-38.7 -61.8 -5.2 +6.2 P-31-45. Nevada blue grass... 15 15 15 204. 45 The number of plants shown in this table represents those living at the beginning of each year's treatment. In 1922 and 1923 the grasses treated were inclined to be later in reaching seed maturity than were untreated specimens. Most bunch grasses produce considerable growth late in the fall, after seed maturity, which if not removed affords an excellent protection for the crown of the plant. This covering doubtless prevents the untreated plants from being killed back as far as the treated ones, and by protecting plants from unfavorable climatic conditions in the early spring enables them to start growth earlier. The results obtained with geranium indicate that frequency of cropping the late growth of that species has no detrimental effect on the vigor or subsequent yield. In contrast to the results obtained with the grasses there was no very perceptible delay in the growth of treated geranium plants over those not treated. The aftermath produced by wild geranium is flattened to the ground by snow, withers, and affords hardly any protection to the young shoots in the spring. The disadvantage in removing the aftermath is that the crown of the plant may be left exposed to the elements, a factor of consequence where the winter temperature is low, the soil freezes deeply, and the wind movement is high. Also, continuous close removal of the late growth is not conducive to the addition of humus to the soil, and by increasing the danger of excessive run-off and erosion it tends to decrease considerably the potential growth capacity of the soil. TABLE 11.-Methods used and results obtained in the harvesting of snowberry First 1 Plants were stripped of their leaves four times at monthly intervals and again at end of season. stripping made two weeks after beginning of growth. Season. One-half of the foliage was removed four times at monthly intervals and leafage was removed at end of Stripped once (two weeks after beginning of growth) and again just before dropping of leaves. • Stripped once late in the season just before dropping of leaves. CROPPING OF BROWSE PLANTS Four methods were adopted for harvesting the foliage of snowberry (Symphoricarpos oreophilus). Vigorous young plants of reasonable uniformity, averaging about 2 feet in height, were selected on a typical range area in the oak-brush type and harvested during the seasons of 1921 and 1922. The methods used and results obtained are shown in Table 11. The method used in Group 1 was the most severe. Four of the plants were killed by the first year's treatment, and the other died after the first defoliation during the second year. In Group 2, where one-half of the foliage was removed at each harvesting, four of the five plants were fairly vigorous at the end of the second year's treatment. In group 3, three of the five plants were vigorous and one was weak at the end of the second year's treatment. In Group 4, in which the plants were merely cropped according to the deferred grazing plan, the best results were obtained. In actual grazing practice a considerable portion of the leafage of browse vegetation usually remains even on closely utilized lands. Such a common range plant as snowberry, however, is susceptible to much the same physiological reactions as herbaceous vegetation in the matter of pasture use. MOISTURE CONTENT OF FORAGE AND ITS SIGNIFICANCE While a certain amount of succulence in range forage is undoubtedly an asset and appears to be associated more or less directly with the gains made by lamb or calf, it is evident from the condition of animals that subsist entirely on very young herbage that, for the greatest food value, forage must not be "watery.' The moisture content of leafage early in the spring-say 10 days or so after growth has started is found to be higher than that of young leafage which develops later in the season, in some instances being as high as 85 per cent. At the beginning of spring growth in some localities livestock losses have resulted from (1) the green feed being sparse and containing only a small amount of "body" and nutriment, and (2) stock grazing little but the green leafage once they had a fair sample of the new growth. A 1,000-pound animal that is not subjected to work or exercise in procuring his feed, as one maintained in a stall or corral, requires approximately 16 pounds of air-dry roughage, such as good hay, every 24 hours as a maintenance ration-that is, a ration ample merely to maintain, not to increase, his weight. When the young feed is short, as, for instance, during the first two weeks after growth begins, it is necessary for an animal to travel over a large area to gather the required 80 pounds or so of this succulent leafage or the equivalent of 16 pounds of air-dry hay. Often an animal, FIG. 13.-Moisture content varies with age of foliage. Average season. especially a cow poorly wintered, can not gather enough of the young growth early in the spring to remain in thrifty, serviceable condition. (Pl. I.) In some cases such an animal can not even gather enough to tide her over the period of recuperation. The moisture content of the forage of such typical and important species as mountain brome, Letterman needle grass, and violet wheat grass is remarkably uniform for a given season or for a particular stage of plant development. Figure 13 shows the average moisture content of a large number of forage samples of violet wheat grass recorded for three years in succession (1916-1918). The plants were harvested (1) once in a season, at the time of seed maturity; (2) twice in a season, 6 and 10 weeks, respectively, after the beginning of growth; and (3) four times in a season, at monthly intervals, the first cut being made four weeks after the growth had started. It is interesting to note that at the time of seed maturity the moisture content averaged 41 per cent. Plants harvested twice in a season, the first herbage removal being six weeks after growth had started, contained an average proportion of moisture of 54 per cent. In contrast to these data, plants cut four times in a season contained an average of 79 per cent of water. FIG. 1.-SECTION OF FORAGE NURSERY, GREAT BASIN EXPERIMENT STATION GIVEN OVER TO CROPPING TESTS FOLLOWING THE PRELIMINARY STUDIES FIG. 2.-CROPPING AT THE TIME OF PROPER FORAGE DEVELOPMENT IS NOT DEVITALIZING TO THE PLANTS UNLESS SUBSEQUENT CROPPINGS ARE MADE BEFORE THE PLANT HAS RECOVERED The vigorous, well devoloped mountain brome specimens to the left show the results of harvesting twice a year, two weeks after growth begins and again five weeks after the first cropping, for three years. The brome specimens to the right were harvested four times in a season for the same period |