Modern Systems of Soil Classification

Although it is the chief purpose of the author to outline and discuss the system of classification proposed by the late Dr. C. F. Marbut as adapted to American soils, it is well to briefly review the fundamentals and earlier systems as a background. Many systems which have been proposed are too technical to have much practical value, while others are too simple to have much scientific value. It seems, therefore, that if the following fundamentals are considered, both requirements may be met

Liming Iowa soils

The use of liming materials on acid soils to supply available calcium and correct soil acidity long has been regarded as a basic principle in the Iowa system of soil management. The beneficial effects are associated primarily with the efficient production of legumes in various cropping systems, thereby contributing to the maintenance of soil fertility and conservation of the soil resources. Many of the important agricultural soils in Iowa were originally well supplied with lime, but through leaching, erosion, decomposition processes, removal by crops and the sale of livestock products there has been a gradual tendency for them to become acid

Few Farms Well Drained

Farmers in north central Iowa have had severe crop losses the last few years because of poor drainage. How much loss

Finer, Better Lime, Please!

During the past 4 years, Iowa farmers have used over 5 million tons of ground limestone, approximately four times as much as in any similar period prior to the AAA Conservation Materials Program. This limestone is helping materially in producing record crops on several million acres of good crop land. But many million acres still need to be mobilized for maximum production by liming

A Study of Certain Green Manure Crops in Making Rock Phosphate Available in Soils

At the present time the world is in the midst of the greatest conflict ever staged. The byword on the lips of every thoughtful American is, Food will win the war. In order that food may be conserved it must first be produced. Therefore, increased crop production must be stimulated. We must produce larger crops upon a given area, that is, intensive farming should be practiced

The measurement of the degree of saturation of soils with bases

1. To determine the degree of saturation of a soil, data must be secured to show the amount of replaceable bases, replaceable hydrogen and base exchange capacity. 2. Experiments have been conducted to determine the accuracy of various methods for these determinations. 3. A study was first made of the electrodialysis method for replaceable bases, using both the Mattson and the Bradfield cells. 4. When 100 grams of soil were electlodialyzed in the Mattson cell for 45 hours, the results seemed satisfactory when compared with the data secured with other methods. 5. When a smaller amount of soil (10 grams) was electrodialyzed in either the Mattson or the Bradfield cell for a shorter time, the end point was not definite and the results could not be considered accurate. Furthermore, there was a continued extraction of basic materials from the soil after more bases had been removed by electrodialysis than were known to be present in a replaceable form in the soil. Hence, it appears that the error in this method may be greater than that caused by solubility effects in the leaching methods. 6. The Hissink (T - S) method for determining the replaceable hydrogen in the soil was compared with the method developed by Parker. 7. In a number of Iowa soils differing widely in characteristics and in soils which had been treated with various amounts of limestone of different degrees of fineness, the Hissink method gave practically the same amounts of replaceable hydrogen. 8. There seemed to be no correlation between the replaceable hydrogen in the soil, when measured by the Hissink method, and the hydrogen ion concentration. With the Webster silty clay loam which had a pH of 7.48, the Hissink method showed more replaceable hydrogen than was found in the Tama silt loam which had a pH of 4.79. 9. The amount of replaceable hydrogen found by the Hissink method was greater in all the soils tested than the total base exchange capacity of the soils. According to Kelley. when this method is used, not only does the barium hydroxide added to the soil react with the exchangeable hydrogen but other side reactions occur. The results with the method are certainly rather unsatisfactory. 10. According to the accepted theories of base exchange, the Parker method for determining replaceable hydrogen is sound in principle and the data secured in this work show that it will give accurate and reliable results. 11. The Parker method for determining the base exchange capacity of soils was also found to give excellent results. The principle of this method has been well established and the method has been used, with certain modifications in technic, by other investigators. 12. After the replaceable hydrogen and base exchange capacity are determined by the Parker method, the amount of replaceable bases and the degree of saturation with bases may be calculated. 13. This method has been tested on a number of Iowa soils and on soils treated with various amounts of lime of different degrees of fineness. In all cases satisfactory results have been secured. 14. In general it is evident that of all the methods tested. that proposed by Parker seems to give the best picture of the actual condition of the base exchange complex in soils. 15. Certain modifications in the technic of this method have been suggested for future work

Choice, Risk, and Moral Judgment: Using Discourse Analysis to Identify the Moral Component of Midwives’ Discourses

Part 1. Communicating risk in healthcare -- Part 2. Communicating risk in legal processes -- Part 3. Communicating risk in social care -- Part 4. Communicating risk in environmental management and biosecurity -- Part 5. Mediating risk -- Part 6. Regulating risk368 page(s

The lowa farmer and world war II

World War II is the biggest fact in the Iowa farm situation. Though Iowa is far removed from air bombing and submarine torpedoing, it is on the battle front so far as economic and social effects of the war are concerned. Iowa’s commercial agriculture underwent terrific strain during and following World War I, and the pressures arising out of World War II promise to be similar, although less severe. It is the purpose of this report to estimate what some of these pressures will be. An understanding of the social and economic forces at work is necessary before plans can be made and action taken to ease the shock of war. The experience of the earlier war helps us to understand these forces, but that experience must be interpreted in light of the changed situation today

Brain-behaviour modes of covariation in healthy and clinically depressed young people.

Understanding how variations in dimensions of psychometrics, IQ and demographics relate to changes in brain connectivity during the critical developmental period of adolescence and early adulthood is a major challenge. This has particular relevance for mental health disorders where a failure to understand these links might hinder the development of better diagnostic approaches and therapeutics. Here, we investigated this question in 306 adolescents and young adults (14-24 y, 25 clinically depressed) using a multivariate statistical framework, based on canonical correlation analysis (CCA). By linking individual functional brain connectivity profiles to self-report questionnaires, IQ and demographic data we identified two distinct modes of covariation. The first mode mapped onto an externalization/internalization axis and showed a strong association with sex. The second mode mapped onto a well-being/distress axis independent of sex. Interestingly, both modes showed an association with age. Crucially, the changes in functional brain connectivity associated with changes in these phenotypes showed marked developmental effects. The findings point to a role for the default mode, frontoparietal and limbic networks in psychopathology and depression.Wellcome Trus