The Use of the Standard Partial Regression Coefficient in Constructing General Botany Achievement Tests

Since 1926, various aspects of the general botany teaching program at Iowa State College have been studied. Victor (1933) and Dietz (1935) described studies dealing with teaching procedures and techniques and evaluation practices. Kreutzer (1935) and Dietz and Gould (1939) reported on certain phases of the testing program, particularly the practice of grouping students enrolled in Botany 101 according to scores made on pretests. Bragonier (1941) described the methods used in constructing and evaluating the pretests. The value of grouping the students for instructional purposes is generally acknowledged within the botany department, however, the means by which the students are grouped is not as well accepted and, consequently, was chosen as the subject for this study

The Relation of Buckthorn to Losses from Crown Rust of Oats

Crown rust is the most destructive disease of oats in Iowa. Losses during the 1930\u27s and early 40\u27s ran high; 30 per cent in 1941. From 1944 to 1948 very little rust occurred, but from 1949 to 1952, loss estimates averaged $45,000,000 per year. The role of buckthorn (Rhammus cathartica L.) as the alternate host of the crown rust pathogen (Puccinia coronata Corda) was discovered by De Bary in 1866. More recent research has shown all species of Rhamnus susceptible to one or more varieties of this leaf rust producing fungus. Occurring in hedges and as escaped bushes in fence rows, R. cathartica constitutes a two-way threat to the oat crop; aeciospores blown from infected buckthorn leaves cause early spring infection of oat fields when weather conditions are favorable; and, new races capable of attacking previously resistant varieties may be formed since hybridization of the fungus occurs each year on the buckthorn leaves

Oaks Dying? Check for Oak Wilt

Oak wilt is known to be established in 59 Iowa counties. But extensive losses can be prevented. This article tells of the disease itself, what research is now being done, and, most important of all, what we can do right now

Seeds of Iowa noxious and common weeds

Weeds are one of the most serious problems faced by the American farmer. Losses due to weeds are estimated at 3 billion dollars annually in the United States. The best way to control weeds is to stop them before they reach the farm. This is true of both noxious weeds and the so-called common weeds which are too frequently taken for granted. It is much easier and cheaper to prevent these pests from establishing themselves than to eradicate them. The seeds of a few kinds of weeds can be carried long distances by natural means. For instance, dandelion seeds are wind-transported; cockleburs and stickweeds are carried by animals. But the seeds of most weeds are spread by man, most commonly planted with crop seed. A good example is the spectacular spread of giant foxtail. Ten years ago this weed was rare in Iowa. Now it is one of the major late summer grassy pests throughout much of the southern half of the state. Giant foxtail has been a successful hitchhiker, mostly with weed-polluted legume seed. It is still on the move, county to county, farm to farm

Recommended Crop Varieties for 1954

Using improved crop varieties is one of the quickests and most effective ways to step up yields. Here are the crop varieties recommended for 1954. Each is backed by long and painstaking experiments and research

Recommended Crop Varieties for 1953

Using improved crop varieties is one of the quickest and most effecitve ways to step up yields. Here are crop varieties recommended for you in 1953. Each is backed by long and painstaking experiments and research

Varieties and Cropping Practices for 1952

United States needs lots of food- for both at home and abroad. Building up grain reserves is a major need. Maximum and efficient production is the goal for 1952, and perhaps for several years to come

Crop Varieties for 1959

Modern crop production methods call for a combination of many factors to maximize farm returns. One of the important decisions you make each year is the choice of crops and varieties that best fit into your total farming operation. And this choice may depend on many factors

Recommended Crop Varieties for 1956

Using improved crop varieties is one of the best ways of getting the most for your money. Here are the crop varieties recommended for 1956. Each is backed by long and painstaking experiments and research