Historical notes ; no. 7

Document describes the origins and history of the Soil Survey with an emphasis on the time periods of 1899-1912, 1912-1920, 1920-1933, and 1933-1952. "For each of the four chronological periods, a brief introductory chapter describes the general political and administrative environment then prevailing, and a summary of the progress of the Soil Survey achieved under such an environment." (p. 36) Also provides information on early soil sampling, typing, mapping, and interpretation. Also tells about the coordination of the National Cooperative Soil Survey and developments in the National Cooperative Soil Survey from 1952-1957

Genomic regions influencing seminal root traits in barley

Water availability is a major limiting factor for crop production, making drought adaptation and its many component traits a desirable attribute of plant cultivars. Previous studies in cereal crops indicate that root traits expressed at early plant developmental stages, such as seminal root angle and root number, are associated with water extraction at different depths. Here, we conducted the first study to map seminal root traits in barley (Hordeum vulgare L.). Using a recently developed high-throughput phenotyping method, a panel of 30 barley genotypes and a doubled-haploid (DH) population (ND24260 × 'Flagship') comprising 330 lines genotyped with diversity array technology (DArT) markers were evaluated for seminal root angle (deviation from vertical) and root number under controlled environmental conditions. A high degree of phenotypic variation was observed in the panel of 30 genotypes: 13.5 to 82.2 and 3.6 to 6.9° for root angle and root number, respectively. A similar range was observed in the DH population: 16.4 to 70.5 and 3.6 to 6.5° for root angle and number, respectively. Seven quantitative trait loci (QTL) for seminal root traits (root angle, two QTL; root number, five QTL) were detected in the DH population. A major QTL influencing both root angle and root number (RAQ2/RNQ4) was positioned on chromosome 5HL. Across-species analysis identified 10 common genes underlying root trait QTL in barley, wheat (Triticum aestivum L.), and sorghum [Sorghum bicolor (L.) Moench]. Here, we provide insight into seminal root phenotypes and provide a first look at the genetics controlling these traits in barley

Soil survey.

Vols. after Series 1963, no. 1 lack series year and numbering.Numbers published 1928-Sept. 1938 and ser. 1934, no. 11 (Nov. 1938) issued without title.Mode of access: Internet.Issued 1928-Oct. 1939 by the Bureau of Chemistry and Soils; Dec. 1939-Nov. 1943 by the Bureau of Plant Industry; Dec. 1943-Jan. 1953 by the Bureau of Plant Industry, Soils, and Agricultural Engineering; 1953- by the Soil Conservation Service; by the Natural Resources Conservation Service.Prepared in cooperation with the various State agricultural experiment stations and other State agencies.Earlier reports in United States Bureau of Soils. Field operations of the Bureau of Soils, 1899-1922.Issues received for locations other than Sci. after Series 1963, no. 1 are not considered part of the series and are cataloged under their individual monograph authors and titles

Applicability of hypoplasticity to reconstituted peat from drained triaxial tests

Proper understanding of the deviatoric behaviour of peats represents a challenge in soil mechanics. Exceptional high compressibility together with extremely high friction angles distinguishes peats from classical organic soils. Considerable amount of triaxial test data on peats can be found in the literature, mostly coming from standard undrained triaxial compression tests. However, only a minor part was intended to describe their prefailure behaviour. Also, limiting the investigation to the undrained response reduces the information on those ingredients of constitutive models, which are necessary to describe the deformational behaviour. This contribution aims to provide better insight into the prefailure deformational behaviour of peats, by analysing in detail the results of non-standard drained tests at various stress paths and undrained tests performed on reconstituted peat samples. Based on the experimental findings, an existing hypoplastic model, originally developed for fine-grained soils, has been adapted to capture the behaviour of peats. The model is directly calibrated on selected experimental results and validated on a variety of different stress path tests. The results reveal the merits of hypoplasticity in modelling the nonlinearity of the prefailure behaviour and the directional response of peats, which both are of great importance when assessing the serviceability limit states of geotechnical structures founded on peats