Thesis Abstract

<p>                <b>ABSTRACT</b></p><p> This thesis is a comprehensive analysis of the effects of seed orientation, row direction and planting population on grain yield, kernel composition, and silage yield and composition. Producers are striving to increase profit by efficiently using their available land area to maximize crop production. However, little research is available testing the effect of seed orientation on grain or silage production. Quantifying the impacts of seed orientation and row direction on grain and silage is essential for maximum crop production. Dissemination of the results should benefit grain and silage producer.<br></p><p> Two experiments were conducted to evaluate the effects of manipulating seed orientation at planting. In the first experiment, maize yield and kernel composition characteristics were evaluated during the 2011 growing season. The first experiment supported yield increases from controlled manipulation of kernels into the soil. This experiment did support that through alternative planting methods, grain and silage yields can be increased compared to the conventional planting methods that are currently practiced. <br></p><p> In the second experiment, maize grain, kernel composition, silage yield and silage composition were evaluated to observe differences from controlled planting methods compared to conventional planting methods during the 2012 growing season. Researchers observed increases in maize grain and silage yield from controlled planting methods compared to conventional planting methods. Differences were observed in direction of leaves in the canopy between planting treatments indicating that plants are able to change the orientation of leaves due to competition of neighboring plants. These studies suggest controlling seed orientation at planting can increase grain and silage yields with no additional changes to production practices. Additional research is warranted to evaluate differences during different growing conditions of different years and to evaluate hybrid differences for planting treatments. <br></p>

Thesis Overview

<p>1.0 INTRODUCTION&nbsp;</p><p>1.1 BACKGROUND&nbsp;</p><p>Maize grain yields have increased from 54.7 bushels per acre in 1960 to 147 bushels per acre in 2011 (United States Department of Agriculture, 2012). Advances in seed genetics and plant health permitting planting densities to increase, and in machinery technology are responsible for these increases in yield. Other factors that may increase rate or efficiency of production would include orientation of kernels in the soil at planting, that can influence germination rate (Patten and Van Doren, 1970) and leaf orientation of plants within the canopy (Fortin and Pierce, 1996), and cardinal direction in which the row is planted, both of which can allow more light to penetrate into the canopy and reach leaves responsible for grain filling. (Karlen and Kasperbauer, 1989). Spacing of plants within a rows can change the amount of light available to a plant; total plant yield can be increased when competition from neighboring plants is reduced (Nielson, 2001). As plant population is increased, the spacing between plants within a row is decreased. The close proximity of other plants will increase interplant competition. By controlling the direction of kernels at planting, direction of leaves can be manipulated in the canopy as the plant grows (Fortin and Pierce, 1996) and potentially decrease the degree of competition. Observations by Fortin and Pierce (1996) indicated that 60-74% of leaves at R1 grew parallel to the direction of the germ when orientation of the kernel at planting was controlled. However, leaves may be reoriented by the plants to capture more light when plants are competing for the same light source (Maddonni et al., 2002), but the degree that re-orientation of leaves can adjust for competition may be limited considering that the direction of incident light changes throughout the day within a field of maize. Planted with their germ facing adjacent rows has increased yield of grain (Torres et al., 2010). In addition, planting seeds with their germ facing other rows also increased grain yields when compared with plants with germ directions being random. Presumably, these responses are attributable to differences in the amount of light that reaches lower leaves within the canopy. An increase in light penetration to lower leaves will increase both grain yield and weight of maize plants (Thomison and Geyer, 2009). To date, little research has been published regarding seed orientation and maize silage production. The amount of grain within maize silage relative to the total amount of plant dry matter will alter the concentration of energy within silage that is available for and digested by animals (NRC, 1996). The objectives of this Master’s Thesis were to: determine the effects of seed orientation, row direction, and plant population on grain yield, grain composition, silage yield, and silage composition. <br></p>