Investigations were conducted at the Cuban Agricultural Experiment Station to determine the comparative growth response and production of fiber of Boehmeria utilis and B. japonica and of 12 types of B. nivea, all of which had been accumulated from various parts of the world. Following the customary commercial practice, three crops were harvested during the growing season. The maximum yield of stems and leaves for the three harvests, under the experimental conditions described, was 41,367 pounds per acre which was produced by type de Francia. The three highest producers of defoliated stems were types de Francia, C, and A, each producing 22,411, 20,328, and 18,999 pounds per acre, respectively. Type C was the leading fiber producer with a production of 565 pounds of dry, degummed fiber per acre. Types de Francia and D were second and third in this respect with a production of 517 and 505 pounds per acre. Types antigua de botanica, Florida, and 15752 were consistently the least productive of the group. By comparison with yields reported in other countries where this plant is grown commercially, the yields obtained from some of the types used in the investigation reported here may be considered excellent. Americana was the most prolific stem producer but at the same time was the shortest growing type. It would seem advisable, through a breeding and selection program, to combine the prolific growth habits of Americana with the more vigorous and high fiber producing capacity of types D, C, or de Francia. As harvests were made successively later in the growing season, the percentage of short, unusable material of the total yield progressively increased as a result of soil moisture deficiency. After the first year of production, however, it is believed that, under Cuban conditions, crops of about equal production might be harvested the end of June, August, and October. Harvesting on these dates would allow each crop to grow for approximately 60 days during the rainy season. Fiber from type Americana was judged to be the finest in texture, followed in order by fiber of de Francia and C, while the fiber produced by type usitatissima was the most coarse in texture. The average percentage of fiber of the green weight of defoliated stems for the 14 types was 2.2. In this respect, type D was outstanding in that it produced an average of 2.8% fiber of the green weight of its stems. The average percentage of fiber of the green weight of ribbons for all types was 8.4. Comparative data are presented on the composition of stems 60 days or less in age and stems 60 to 120 days in age which show that the relative percentages of fiber and ribbons are practically identical in the different aged stems. These data would suggest, as far as percentage of fiber is concerned, that harvesting should be done as soon as the ultimate height of the crop is reached. Based on the experimental data and information obtained, types C, de Francia, and D appear to be better adapted for production under Cuban conditions, at least from the standpoint of yield of fiber, than the remainder of the 14 types tested.

Indiscriminate use of 2, 4-D or hormone type weed sprays in the 1945 season in southern New Mexico resulted in very abnormal growth of cotton in adjacent areas, the amount of injury depending on degree and time of contamination. Materials used for the experiments presented herein were not absorbed from the ground surface or leached from dead weed tops to any extent by irrigation water. Observations on spray drift indicated that injury in commercial cotton fields extended over distances far too great to be explained by actual spray drift. Evaporation and distillation tests indicated that tested materials known to contain an "esterified" 2,4-dichlorophenoxyacetic acid were highly volatile when exposed directly to the sun in summer months, adjacent cotton plants being seriously injured by the vapor. It is concluded that highly volatile materials or other formulae prepared in any manner that are highly conducive to transportation by air currents cannot be used safely during the summer months in intensive cotton growing areas such as those in southern New Mexico. Materials containing unmodified 2,4-dichlorophenoxyacetic acid or a salt thereof were nonvolatile and could be used with safety very close to cotton plants when care was taken to control actual spray drift. The extreme sensitivity of the cotton plant is indicated by results showing that only 0.01 cc of solution containing 1,000 p.p.m.;. of ammonium salt of 2,4-dichlorophenoxyacetic acid caused development of abnormal foliage on rapidly growing cotton plants in midseason. Degree of injury varied with amount applied, and symptoms were more quickly evident when applied to top than to bottom or middle leaves. When applied as a spray to entire plants, 1 p.p.m. caused injury from which plants recovered, while 10 p.p.m. caused serious injury and prevented normal fruit set; however, growth of the plant in height was almost normal.

Results obtained with petroleum oils in controlling weeds in guayule seedings are reported in this paper. Adequate control of weeds in nurseries or field seedings was obtained by spraying the areas with a mixture of three-fourths stove oil and one-fourth diesel oil applied at the rate of 32.4 gallons per acre or 1.2 gallons per nursery bed 4 X 400 feet. It was necessary to make the first application of oil while the weeds were in the cotyledon stage or about 2 weeks after seeding when the weeds and also the guayule were susceptible to the oil. However, the guayule was so much more resistant to the oil that almost complete killing of the weeds and no killing of the guayule was obtained. Oil spraying resulted in a temporary set-back in the growth of the guayule, but by the end of the growing season there was no difference between the weights of the tops of plants in oiled and hand-weeded plots. Results from greenhouse tests indicated that guayule seedlings should be sprayed with the oil at air temperatures between 70 degrees and 80 degrees F. A great many plants were killed when sprayed with the oil at 50 degrees and 94 degrees F. The results also suggested that whenever the seedlings have been subjected to unfavorable growing conditions such as cold weather or drought prior to oil spraying, their resistance to the oil was greatly reduced. No difference was obtained between the growth of lettuce in soils that had not been sprayed with oil and those that had received a total of 250 gallons of diesel oil or 300 gallons of stove oil to the acre, thus indicating that there was no residual effect on the soil from applications of oil in much greater amounts than would be applied for weed control in guayule seedings.

The pollinating insects of alfalfa in Utah were studied during 1943 and 1944 to determine (a) the species of economic importance, (b) their abundance and habits, and (c) the influence of ecological factors on their pollinating activities. In Utah bees play an essential role in the commercial production of alfalfa seed. Tripping of blossoms occurred, almost without exception, only during the working hours of bees, and as a rule the amount of tripping in the fields was proportional to the number of pollen-collecting visitors. The flower structure of alfalfa is adapted to pollination by insects, and practically no tripping occurred on plants from which bees were excluded. The production of a 500-pound seed crop per acre, it is estimated, would necessitate the tripping of at least 38 million flowers. In most of the fields observed there was an insufficient number of tripping insects to accomplish that amount of tripping. A scarcity of tripping insects may therefore be an important factor contributing to the present low seed yields. The flowers producing the alfalfa seed crop in Utah are tripped mainly by the following kinds of bees listed in order of their importance: Pollen-collecting honeybees, Nomia or the alkali bee, and Megachile or leaf-cutting bees. Honeybees are most valuable to alfalfa tripping in areas where they collect alfalfa pollen; Nomia is the leading tripping insect only near its isolated nesting sites; while Megachile populations are so widely dispersed that nowhere were they the leading tripping agent, but they aid substantially in the tripping in many localities. Competitive plants in the environment of alfalfa fields probably determine in large measure where and when bees will work alfalfa for pollen. Nomia appeared to prefer white sweetclover; Megachile the gumweeds; and honeybees preferred mustards, clovers, thistle, and chicory. Cultural practices may influence the pollen-collecting activities of honeybees on alfalfa. Honeybees were collecting pollen from fields of nonsucculent, slow-growing alfalfa, while little or no pollen collection was in progress on more succulent fields nearby. Honeybees were working the succulent fields for nectar, but nectar-collecting bees usually trip few alfalfa blossoms. On plots from which DDT had eliminated Lygus and thrips, however, alfalfa flowered profusely on very long racemes, and many blossoms were being tripped by nectar-collecting honeybees. Applications of sulfur-pyrethrum appeared to repel bees for 2 or 3 days. Although honeybees are now the predominant trippers of alfalfa in Utah, seed yields are much lower than when wild bees were depended upon for tripping. Honeybees did not collect pollen from all fields, but only from those growing under conditions where competing pollen sources were at a minimum. Even in favorable areas they appeared to select fields for pollen collection which were in an attractive state of growth, collecting only nectar from others.

This research, originally under the auspices of Professor van Vuuren, was accepted by Professor Edelman after the war because of a vacuum in the Social Economic Department of the Agricultural University. Because of the change of promotors the description of the physical environment was extended. The development of Huissen was closely dependent on the history of the River Rhine, on whose bank it was originally founded near the bifurcation of the Rhine and Yssel. After the diversion of the bifurcation and its silting up Huissen lost its importance as a trading centre. The sandy soil, after which the hamlet of Het Zand was named, consisted of deposits of dike breaks and of breaks in the natural levees before the dikes were built. On these sands tobacco cultivation was introduced in the eighteenth century. After its disappearance this crop was in turn followed in the 19th century by the introduction of market-gardening and fruit- growing both for the nearby town of Arnhem and especially for the rapidly developing industrial area of the Ruhr.The social and economic conditions of farmers and farmworkers throughout its history and at present were fully discussed.Prospects for the development of Huissen as a horticultural centre after the severe damage of the Second World War were considered.