The ambiguity of current tillage nomenclature has led to much confusion. This report explains a uniform, comprehensive tillage index that was developed to avoid that ambiguity. It is based on row topography, residue cover, roughness, and tillage depth that result from passage of the tillage tool rather than on the tillage tool used. Examples of the use of this tillage index are presented. This index, because of its percentage crop residue cover and potential surface water storage components, will be useful when the Universal Soil Loss Equation is to be used for estimating erosion potential on a given field.

The draft of a moldboard plow increases with forward speed. It has been demonstrated that this increase in draft can be controlled by reducing the lateral cutting angle as speed increases. This paper describes some spring-damper mechanisms used to control the lateral cutting angle of a moldboard plow bottom.

A rainfall simulator was used to evaluate the effects of six different tillage practices on soil and water losses from continuous corn for three soils in Iowa. Soil loss decreased as tillage decreased. Percent of soil covered by corn residue explained between 78 and 89 percent of the variance in erosion among tillage systems. The effect of non-uniformly distributed corn residue on controlling erosion was greater than expected based on a published mulch factor. Runoff amounts decreased as residue cover increased for two of the three soils studied. No critical slope length limits were found for the tillage practices, soils, slopes, and slope lengths studied except for till-planting on the Ida soil. As sediment concentrations increased, mean sediment size increased for one soil, decreased for a second soil, and was unrelated to sediment concentration for the third soil.

The main objective of farming is to grow energy in the form of digestible nutrients. Although the farmer measures his corn production in bushels per acre and his hay production in tons per acre, this does not give him a true measure of his productivity.

A moldboard plow was modified such that the ap-proach-angle of the bottoms could be varied and held at a given angle by a hydraulic cylinder. Field tests of this plow verified that good plowing performance could be obtained at high travel speeds when the bottoms were operated at an approach-angle less than the design approach-angle.

An analysis of rotary lawn mower accident statistics showed that measures must be undertaken to reduce or to guard against the hazards of operating these machines. A cantilever rod blade guard was designed, built, developed, and tested. The rotary mower, when equipped with a blade guard, mowed the lawn satisfactorily and yet, when encountering a test object (a dressed chicken), passed over it without inflicting injury to the test object.

Evaluation of mechanical damage has always been one of the most elusive problems associated with the harvesting, handling, and marketing of corn. Although greatly needed, there is no standard method to describe the quality of corn from the standpoint of physical or mechanical damage.

The development of a chassis suspension system for an agricultural tractor has been described to improve the operator ride comfort. Computer simulation tech-niques were used to formulate the tractor models and to compute the natural frequencies and frequency response of the models, as well as the RMS acceleration response, to evaluate the effect of the suspension system and cab position on operator ride comfort.

This study investigated what percentage of the corn kernel damage was caused by the cylinder and the concave before and after the kernels were shelled from the cob and the effects of kernel moisture contents, cylinder speeds, and the different con-cave zones on these two categories of damage.

STANDING in the field, unhusked corn is undamaged and can last almost indefinitely in that state with-out diminishing its food value. Deterioration begins with the mechanical process of harvesting, and practically every subsequent operation in drying, transporting, and handling further decreases the quality of the grain. The rate of deterioration is dependent on the initial injury sustained during such mechanical processes, particularly the harvesting operation. During harvesting, the kernels are subjected to damaging impact and compressive forces that result in breaches of the seed coat or cracks in the pericarp of the kernel.