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Spring barley (Hordeum vulgare L.) is an important cereal crop in Quebec, where it is used as a crop for swine and poultry. Since barley is a better source of energy than protein, a protein supplement must be added to the feed. Consequently, the production of barley with high protein concentration in the grain (GPC) is desirable. Studies on intensive cereal management (ICM) practices in other countries have shown that high yields can be combined with a high GPC. From 1987 to 1990 three field experiments were conducted to evaluate the effects of ICM on the yields and GPC of six-rowed spring barley in Quebec. Our results describe the effects of individual ICM components (N fertilizer application, fungicide, and plant growth regulator) on the development of yield components and on GPC. In general, N had little effect on main stem yield spike$ sp{-1}$ and on tiller spikes m$ sp{-2}$. Possibly, plant density or environmental conditions may have imposed greater limitations on yield rather than N. Nitrogen treatments increased GPC generally by increasing the amount of protein grain$ sp{-1}$. Nitrogen treatments which increased the amount of protein grain$ sp{-1}$ increased the lysine and cyst(e)ine concentrations of the grain but decreased their concentration in the grain protein. The plant growth regulator ethephon increased GPC by increasing the amount of protein grain$ sp{-1}$, by decreasing the nonprotein content grain$ sp{-1}$, or by altering final grain size distribution. Ethephon often had damaging effects on yield. Large genotypic variation was observed for GPC, but could not be related to genotypic differences in N harvest index, total N accumulation, protein yield or post-anthesis N uptake and assimilation. Grain yield was weakly correlated with GPC. Examination of the cultivars grown from 1910 to 1988 showed that increases in grain yield were accompanied by increases in harvest index, total dry matter, and lodging resistance. Plant height was reduced over tim

An experiment was conducted for two years to determine the effect of seeding rate, and nitrogen fertility on the yield and quality of hard red spring wheat (Triticum aestivum L.) in Quebec. The experiment was conducted on a Ste-Rosalie series soil (humic gleysol), in the St-Hyacinthe region, 50 km east of Montreal. The design of the experiment was a split-plot design. The treatments in the main plots were the plant densities while the nitrogen treatments (rate of nitrogen, number and timing of the applications and formulation of fertilizer nitrogen) were applied to the sub-plots. Nitrogen had a significant effect on yields in 1987, but not in 1986. Maximum yield was 6838 kg ha$ sp{-1}$ in 1986 and 3807 kg ha$ sp{-1}$ in 1987. Protein concentration was increased by higher nitrogen rates in both years. The yield and protein concentration were affected by low precipitation in 1987. Applying the nitrogen later in the season increased the protein concentration in both seasons. It also decreased yield in 1987, but this was caused by lack of water in late June and July 1987. Formulation of nitrogen fertilizer did not have an effect on yield and protein content of the crop.

The objectives of this study were to evaluate the effects of earlier corn (Zea mays L.) harvest, on corn yield, intercrop growth, and soil N levels, and to evaluate the effects of red clover (Trifolium pratense L.) compared to ryegrass (Lolium multiflorum Lam.) as intercrops on corn yield and soil N levels. / After two years, earlier corn harvest did not result in greater intercrop growth or higher soil N levels compared with later corn harvest and there was no significant soil N contribution by legume intercrops in either harvest period. Thus, no soil N benefit was found from using intercrops in earlier harvest for silage compared to later harvest for grain corn, nor from using red clover compared to ryegrass as an intercrop. / In the early harvested silage system, a quadratic corn yield response to added N suggested that near-maximum corn dry matter yields were obtained at the rate of 140 kg N ha$ sp{-1}$. Maximum total dry matter yields were not obtained in the late harvest grain system in any site-year. Legume and non-legume intercrop species had similar effects on corn yield.

Agriculture remains a dominant economic sector in many developing countries. Rice constitutes a staple food for more than half of the world's population and is the main meal of all Lao people (FAO, 2005). However, rice production faces many problems, including the effects of floods, drought and poor soil quality. These challenges combine to reduce rice productivity below what might be possible. However, before new agricultural policies are put in place, it is important to identify the factors associated with rice production efficiency. This thesis analyses technical and socio-economic factors that influence rice production and estimates the level of technical efficiency of individual rice farmers in Ban Home, Laos. / Survey data were collected in the region in 2003, for both wet season and dry season rice production. Using these data, a Cobb-Douglas frontier production function was estimated for each season using two approaches, deterministic and stochastic. During the wet season, several factors were statistically significant and positive in their effect on rice yield: area in rice production, level of fertilizer use, total labour, the use of a modern variety, sandy soil and contact with a professional agricultural advisor. During the dry season, only area in rice production and fertilizer were significant. Based on the frontier production functions, it is possible to conclude that the average technical efficiency of farmers is higher during the dry season than the wet season, for both the deterministic and stochastic approaches. / However, socio-economic factors were unable to explain the level of technical efficiency among farmers, when evaluated using a standard regression approach. By using a simple t-test to compare the mean level of efficiency of different groups of farmers, some significant differences emerged. Farmers who used credit were found to be more efficient than those who did not. Moreover, experienced farmers were more efficient than less experienced farmers. Also, farmers with less than 7 years of education were more efficient than more educated farmers.

Typescript. / Thesis (Ph. D.)--University of Hawaii, 1967. / Bibliography: leaves 156-169. / 169 l

Thesis (D.Phil.(Agricultural extention))-University of Pretoria, 2007. / Includes bibliographic references (leaves 191-199).

Minor Thesis (Ph. D.)--Cornell University, June 1912. / Typescript.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1970. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliography.

Thesis--Auburn University, 2009. / Abstract. Vita. Includes bibliographical references (p. 65-71).