Effect of time, depth and method of plowing upon yield and eradication of biennial sweet clovers

From the standpoint of amount of dry matter and nitrogen added to the soil and the eradication of the plants, sweet clover may best be plowed for corn about April 25 to May 5. The five dates of harvest used rank as follows in yield of dry matter for tops and roots: May 3-18, Nov. 1-13, Oct. 1, April 9-13 and Sept. 1. Nitrogen yields rank in much the same order. Of the total for tops and roots, the tops contained 68 percent of the dry matter and 73 percent of the nitrogen in September, 51 and 48 percent, respectively, in October, 29 and 18 in November, 24 and 28 in April and 69 and 74 in May. In September the tops contained 3.5 percent nitrogen and the roots 2.8, October 3.0 and 3.4, respectively, November 2.1 and · 3.9, April 5.4 and 4.5 and May 3.4 and 2.6. In April the roots contained 61 percent as much dry matter and 69 percent as much nitrogen as in November. In April, however, tops and roots together contained 80 percent as much dry matter and 96 percent as much nitrogen as the roots alone in November. White sweet clover was superior to yellow in yield of dry matter in the tops, while yellow was superior to white for roots. For tops and roots there was little difference. Yellow survived somewhat more than white, but the difference was small. Plowing Sept. 1 killed nearly all of the sweet clover but with a sacrifice of approximately one-half of the dry matter and nitrogen. Plowing in October and November caused costly eradication problems since approximately 20 plants per square yard survived. The Pulverator plow was less effective than the ordinary plow in exterminating the clover for September, October, November and April plowings. A depth of plowing recognized as providing good tillage practice is to be preferred. Draft requirements were in direct proportion to the depth of plowing, and the ordinary plow required practically the same amount of draft as the Pulverator. Draft required increased progressively for September, October and November plowings, dropped sharply for April and increased for May over April. Pasturing yellow sweet clover from Aug. 15 on reduced the survival nearly 50 percent. Plants buried by hand survived directly in proportion to length of roots for 1, 3, 5 and 7-inch lengths, and inversely in proportion to depths of burying for 3, 5 and 7-inches. Fewer of the small roots survived than of the large ones. Plants transplanted in normal position had an average of eight buds per plant. On the plants that survived 51 percent of the buds produced shoots. Under field conditions there were approximately two shoots per plant. Large roots had more buds than small ones, but practically the same percentage of buds grew from large roots as from small ones. Following dormancy buds did not grow at temperatures of 28 and 30° F., increased an average of 0.5 cm. in length in 32 days at 36°, 1 cm. at 40° and 4 cm. at 50°

Choosing legumes and perennial grasses

Many letters are received annually by the Iowa Agricultural Experiment Station requesting information on the different legumes and grasses. This publication has been prepared to answer the more important questions pertaining to the choice of legumes and grasses for different uses and conditions.2 Legumes of greatest value for different uses or soil conditions in Iowa are (1) alfalfa, (2) medium red clover, (3) mammoth red clover, (4) alsike clover, (5) white clover, (6) the biennial white and yellow sweet clovers, (7) hubam clover, (the annual white sweet clover) (8) Korean lespedeza, (9) dalea and (10) soybeans. A discussion of soybeans is largely omitted in this publication since the growing of this crop is entirely different from that of the others.

The significance and technique of dry matter determinations in yield tests of Alfalfa and red clover

In comparative yield tests of species, varieties, strains, sources or lots\u27, or of cultural treatments of forage crops, the objective of the investigator is to obtain the most accurate results possible with funds available. The methods employed must be capable of distinguishing differences in yields of dry matter of individual plots attributable not only to the lot but also to soil heterogeneity and other environmental conditions. Accurate dry matter determination of forage on the plots of an experiment is of major importance to the experimenter. Under humid conditions reliable comparisons cannot be made from the weights of field cured forage, except on rare occasions that cannot be predicted. Some investigators believe that with fairly homogeneous forages the error introduced from the use of green weights without dry matter determinations is not great

Soybeans for Iowa

Soybeans have been under continuous observation and test at the Iowa station since 1910. As the value of soybeans for Iowa farmers became apparent, more attention was given to the crop until the investigational work has become quite comprehensive. Interest in the crop was not evident thruout the state until about 1916, but has since been keen, and the acreage in many counties has increased remarkably. While the soybean acreage in Iowa is not large as compared with some of the other Iowa crops, the fact that it has more than doubled annually thru a series of years is significant

Sudan grass

Sudan grass is one of the most satisfactory non-leguminous emergency hay and pasture crops available for use in Iowa. It has been under observation at the Iowa Agricultural Experiment Station during the past 14 years. Three hundred ninety-eight experimental seedings have been made with it in the past 11 years. It surpasses oat hay from the standpoint of yield and has about the same feeding value as either oat hay or timothy. Since it is not a legume, it cannot utilize the nitrogen from the air and does not have the feed value of such crops as the clovers, alfalfa or soybeans. Being an annual, it does not compete with clover, alfalfa or timothy, which live for more than one year. It is not recommended as a regular crop in the rotation, but possesses merit as an emergency or catch crop which can be used to advantage for hay, pasture or soiling

Fisher waves in the strong noise limit

We investigate the effects of strong number fluctuations on traveling waves in the Fisher-Kolmogorov reaction-diffusion system. Our findings are in stark contrast to the commonly used deterministic and weak-noise approximations. We compute the wave velocity in one and two spatial dimensions, for which we find a linear and a square-root dependence of the speed on the particle density. Instead of smooth sigmoidal wave profiles, we observe fronts composed of a few rugged kinks that diffuse, annihilate, and rarely branch; this dynamics leads to power-law tails in the distribution of the front sizes.Comment: 4 pages, 2 figures, updat

Soybeans in Iowa farming

Few other crops in Iowa have shown such rapid acreage increases as soybeans or proved as advantageous for so many different uses. Only 471 acres of the crop were grown in the state in 1919. By 1933 the area had expanded to 192,000 acres. Soybeans may be planted either alone or with corn. Alone, they may be used for seed, hay, pasture, silage, soiling, or as a green manure crop. The first two of these uses are by far the most important. Iowa farmers need a home-grown, high protein concentrate, and soybeans are the best crop available for that purpose. Soybeans also are grown extensively to provide a high protein roughage, because on many farms they are better suited to the soil and crop program than alfalfa and are more certain and productive than red clover

Determination of the Antiferroquadrupolar Order Parameters in UPd3

By combining accurate heat capacity and X-ray resonant scattering results we have resolved the long standing question regarding the nature of the quadrupolar ordered phases in UPd_3. The order parameter of the highest temperature quadrupolar phase has been uniquely determined to be antiphase Q_{zx} in contrast to the previous conjecture of Q_{x^2-y^2} . The azimuthal dependence of the X-ray scattering intensity from the quadrupolar superlattice reflections indicates that the lower temperature phases are described by a superposition of order parameters. The heat capacity features associated with each of the phase transitions characterize their order, which imposes restrictions on the matrix elements of the quadrupolar operators.Comment: 4 pages, 5 figure

Proximity effect of vanadium on spin-density-wave magnetism in Cr films

The spin-density wave (SDW) state in thin chromium films is well known to be strongly affected by proximity effects from neighboring layers. To date the main attention has been given to effects arising from exchange interactions at interfaces. In the present work we report on combined neutron and synchrotron scattering studies of proximity effects in Cr/V films where the boundary condition is due to the hybridization of Cr with paramagnetic V at the interface. We find that the V/Cr interface has a strong and long-range effect on the polarization, period, and the N\'{e}el temperature of the SDW in rather thick Cr films. This unusually strong effect is unexpected and not predicted by theory.Comment: 7 figure

Laser Spectroscopy for the Study of Exotic Nuclei

Investigation into the properties and structure of unstable nuclei far from stability remains a key avenue of research in modern nuclear physics. These efforts are motivated by the continual observation of unexpected structure phenomena in nuclei with unusual proton-to-neutron ratios. In recent decades, laser spectroscopy techniques have made significant contributions in our understanding of exotic nuclei in different mass regions encompassing almost the entire nuclear chart. This is achieved through determining multiple fundamental properties of nuclear ground and isomeric states, such as nuclear spins, magnetic dipole and electric quadrupole moments and charge radii, via the measurement of hyperfine structures and isotope shifts in the atomic or ionic spectra of the nuclei of interest. These properties, when measured with sufficient precision for a long range of isotopes, offer prominent tests of recently developed state-of-the-art theory and help to stimulate new developments to improve the many-body methods and nucleon-nucleon interactions at the core of these models. With the aim of exploring more exotic short-lived nuclei located ever closer to the proton and neutron driplines, laser spectroscopy techniques, with their continuous technological developments towards higher resolution and higher sensitivity, are extensively employed at current- and next-generation radioactive ion beam facilities worldwide. Ongoing efforts in parallel promise to make even more exotic species available for study at next-generation facilities. Very recently, an innovative application of laser spectroscopy on molecules containing short-lived nuclei has been demonstrated offering additional opportunities for several fields of research, e.g. fundamental symmetry studies and astrophysics.Comment: 129 pages (bibliography 56 pages), 32 figures, invited review for Progress in Particle and Nuclear Physics. Comments and suggestions are welcom