Thesis (Ph. D.)--Ohio State University, 2009. / Title from first page of PDF file. Includes vita. Includes bibliographical references (p. 91-95).

Thesis (Ph.D.) - University of Queensland, 2005. / Includes bibliography.

Thesis (M. Phil.)--University of Hong Kong, 2004. / Title from PDF t.p. (viewed on Dec. 19, 2005). Includes bibliographical references (leaves 144-163). Also issued in print manuscript.

Master of Science / Department of Biological & Agricultural Engineering / Daniel Flippo / In 2050 the world’s population is projected to be over 9 billion people, creating a need for more agriculture production than ever before. One way to increase production of crops is to get them planted in an optimum planting window. This allows the crops to take the most advantage of the longer days during the growing season thus increasing their yield. The growing size of farms and reduced amount of farmers puts more pressure on each remaining farmer to mechanize more heavily, and to get more acres planted faster in order to get crops planted in time. Most areas have an optimal planting window of a few weeks. This drives a need for planters to get bigger so one man can plant more acres in a day. Besides getting bigger, planters are also getting able to accurately plant faster. Today many of the new planters are “high speed,” meaning they are able to plant at speeds of 7 to 10 mph. The typical research and discussions of high speed planters tend to focus on the speed effects on the seed placement, emergence, planting rates, active downforce systems, metering systems etc. There is little discussion on the effects these higher planting speeds have on the draft requirements of the row unit itself. There needs to be more knowledge about the relationship between soil and planting tools in order to optimize power and performance of the tools to minimize fuel consumption, labor, and soil compaction. In order to test the draft forces of various tillage and planting tools in different field conditions there needs to be a machine that can repeatedly test multiple tools in multiple field conditions over a wide range of speeds. This paper is about the development of such a machine. The Cultivation Assessment Test Apparatus (CAT App.) is a device used to pull tillage and planting tools at a consistent depth at different speeds measuring the draft and downforce requirements during tests.

Master of Science / Department of Agronomy / Ignacio Ciampitti / Genotype by seeding rate interaction can play a critical role in wheat (Triticum aestivum L.) yield potential. The objectives of this study were to i) quantify wheat yield response and ii) early-season plant establishment related to the planting technology under diverse seeding rates and with contrasting varieties relative to their tillering ability. Four studies were established at two locations during two growing seasons (2015-16 and 2016-17) at Ashland Bottoms (dryland and conventional till in the first year and no-till in the second year) and at Topeka (irrigated and no-tillage for both years) field research stations (KS, US). Two winter wheat varieties were planted with two different planting systems (singulated and conventional drill) at four different seeding rates (45, 90, 135, and 180 kg ha⁻¹). Early-season measurements consisted of stand counts, canopy coverage (estimated via imagery collection via small-unmanned aerial vehicle systems - sUAVS), determination of early-season gaps within the stand of plants, and spacing between plants. Early season measurements (emergence progression, stand count, and canopy coverage) and biomass did not present differences among treatments. At Ashland, across 2-yrs, single factors seeding rate and genotype significantly impacted yields. Seeding rate factor positively affected yields, ranging from 4.7 to 5.4 Mg ha⁻¹ with seeding rates going from 45 to 135 kg ha⁻¹, respectively. For the genotype factor, the variety WB Cedar (high-tillering) presented an overall yield of 605 kg ha⁻¹ greater than WB 4458 (low-tillering). Across locations, the seeding system did not influence yields for both years of the study. At Topeka, the seeding system significantly influenced yields in 2017, with singulation outyielding the drill system, in 161 kg ha⁻¹. Further research is needed at a farmer-scale testing more winter wheat varieties and focusing on lower seeding rates to better understand the potential benefits of the implementation of this new technology.

Experiments were conducted to evaluate the most profitable and effective management practices for non-irrigated soybean production. Common production practices were compared side by side to evaluate yield response and economic returns. Combinations of row spacings and planting dates were evaluated to determine interactions between the two factors and also the effects on yield. Lastly, the effectiveness of various iron sources was examined in iron deficiency chlorosis (IDC) susceptible soybeans when applied foliar, inurrow at planting, and a split application. These data suggest that in non-irrigated soybeans, “low input management” practices do not maximize yields, but can be more profitable, depending on soybean market price and input costs, when compared to “full management”. Results also reveal that no interaction between row spacing and planting date occurred with respect to soybean yield. However, planting date did influence soybean yield with the earlier planting dates, mid-April, and mid-May providing the greatest yield. When examining row spacing, soybean grown on rows spaced 38.10 cm apart resulted in greater yield when compared to those grown on 96.52 cm rows. The iron product that consistently provided the greatest visual reduction of IDC symptoms was Sequestar 6% EDDHA chelate applied at 0.20 and 0.27 kg ai ha-1. This treatment was only effective when applied inurrow at planting. However, it was found that soybean yield was not influenced by any iron product or application timing, indicating that visual symptoms of IDC may be managed, but that the visual reduction in symptoms does not translate into yield.

High tunnels have been used for many years worldwide. However, there has been limited research about use of high tunnel technology in the southeastern United States and its popularity has recently increased in Mississippi. A planting date study of 'Roma'' tomato, 'Legend' tomato, 'Ichiban' eggplant, 'Sweet Banana' pepper, ‘Benary’s Giant’ zinnia and ‘Potomac Red’ snapdragon was conducted in spring 2010 in three high tunnels in Starkville, Mississippi. Results showed for most cultivars (tomatoes, eggplant and pepper) a 12 Mar. 2010 planting date did not differ in marketable yield from planting on 2 Apr. 2010. In 2011, a fertilizer study on Encore lettuce mix and Ovation green mix was conducted both in high tunnel and in the field. Results indicated there was no effect of vermicompost tea or fertilizer treatments on yields of salad mixes.

Three types of oak planting stock were evaluated to determine their influence on survival and initial growth. Planting stocks utilized include conventional containerized seedlings with a 240 cm3 container, 1-0, bare-root seedlings, and Root Production Method (RPM™) seedlings with a 11.4 L container. Initially after outplanting and at the conclusion of the first and second growing seasons, height, groundline diameter (GLD), and survival were assessed. Study sites are located in southern Mississippi on lands disturbed by Hurricane Katrina. Species planted were swamp chestnut oak (Quercus michauxii Nutt.) and Nuttall oak (Q. texana Palmer). A total of 3,600 seedlings were planted in this study: 300 seedlings for each of the six planting stock/species combinations per site. Statistical comparisons of growth and survival among species and planting stock types were performed. RPM™ and bare-root planting stocks exhibited similar growth and survival, while the conventional container stock had significantly lower growth and survival.

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