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3 pp. / The optimum planting by elevation is presented for small grains in Arizona. The influence of planting date on crop development, grain yield and frost risk is discussed.

Potential impacts of climate change on grain sorghum (Sorghum bicolor) productivity were investigated using the CERES-sorghum model in the Decision Support System for Agrotechnology Transfer v4.5. The model was first calibrated for a sorghum cultivar grown in a free air CO2 enrichment experiment at the University of Arizona, Maricopa, Arizona, USA in 1998. The model was then validated with an independent dataset collected in 1999. The simulated grain yield, growth, and soil water of sorghum for the both years were in statistical agreement with the corresponding measurements, respectively. Neither simulated nor measured yields responded to elevated CO2, but both were sensitive to water supply. The validated model was then applied to simulate possible effects of climate change on sorghum grain yield and water use efficiency in western North America for the years 2080-2100. The projected CO2 fertilizer effect on grain yield was dominated by the adverse effect of projected temperature increases. Therefore, temperature appears to be a dominant driver of the global climate change influencing future sorghum productivity. These results suggest that an increase in water demand for sorghum production should be anticipated in a future high-CO2 world.

Thesis (M.Sc. (Agronomy)) --University of Limpopo, 2015 / Soybean (Glycine max (L.) Merrill) is considered to be an important grain legume and an oil crop. It is also important in livestock feeding and improvement of soil fertility through biological nitrogen fixation (BNF). Until recently, soybean was not widely grown by smallholder (SH) farmers in Africa. This has led to breeding of promiscuous varieties to ensure wide adoption of the crop by SH farmers, without the use of inoculants or expensive nitrogen fertilizers. Field and glasshouse experiments were conducted during 2012/2013 growing season. One commercial (specific) variety Dundee and three naturally-nodulating (promiscuous) soybean varieties (TGx-1937-1F, TGx-1740-2F, TGx-1835-10E) were evaluated in a field trial for their growth, nodulation and yield response to B. japonicum strain WB74 inoculation. Seed inoculation in the field enhanced chlorophyll content, number of nodules, nodule dry weight, and the percentage of active nodules, number of pods, hundred seed weight, shelling percentage and grain yield. Varietal differences exerted significant (P≤0.05) effect on all field parameters evaluated except on nodule number and percentage of active nodules. TGx-1937-1F achieved the highest number of nodules (28 per plant) while the highest percentage of active nodules (69%) was achieved by TGx-1740-2F. Huge effect of inoculation was observed on Dundee variety, and resulted in significant grain yield increases (237.8%) while smaller gain increases were observed in TGx-1740-2F (43.9%) and TGx-1835-10E (38.7%). The yield of TGx-1937-1F did not respond to inoculation. Two promiscuous (TGx-1937-1F and TGx-1740-2F) varieties and one commercial (Dundee) variety were evaluated in a glasshouse trial for their growth and nodulation response to inoculation in different soil types (sandy clay loam, sandy loam, loamy sand) of Limpopo Province. In the glasshouse inoculation showed effect on chlorophyll content only, and effect of soybean variety was found to be significant on days to flowering, chlorophyll content, plant height, number of nodules and root dry weight. Soil type showed significant effect on all parameters evaluated in the glasshouse study except on nodule dry weight. Loamy sand soil from Ga-Molepo gave tallest plants and highest nodule number at 61 cm and 29 nodules/plant compared to other soils. All soils evaluated in the study resulted in percent active nodules ranging from 74.5% to 77.4% showing possibility of presence of cowpea-type rhizobia in Limpopo soils capable of fixing atmospheric nitrogen. Inoculation x variety interaction was significant on days to flowering, plant height and chlorophyll content. Inoculant application in TGx-1740-2F variety reduced the number of days it took to flowering from 61 to 54 days and increased its plant height by 57% from 44.8 to 67.9 cm. Eighty three percent (83%) increase on chlorophyll content of variety Dundee was observed due to effect of inoculation. Inoculation x soil type interaction had significant effect on plant height and dried plant biomass. Varity x soil type interaction influenced chlorophyll content, while the interactive effects of inoculation x variety x soil type were significant on chlorophyll content only. The study showed that it is beneficial to inoculate the soybean varieties studied, especially the commercial variety Dundee, in order to enhance their growth, nodulation and yield. / Department of Agriculture Forestry and Fisheries

Made available in DSpace on 2014-06-11T19:30:25Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-09-14Bitstream added on 2014-06-13T19:00:33Z : No. of bitstreams: 1 cantanhede_isl_dr_botfca.pdf: 282689 bytes, checksum: dd38b2f155b6e8aa6283f11edddce736 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O objetivo deste trabalho foi avaliar o desempenho de novos híbridos de mamona no período de safra e safrinha em relação às características produtividade de grãos (PG), altura média da planta (AP), teor de óleo das sementes (TO), diâmetro do caule (DC), altura de inserção do racemo primário (altura do caule - AC), número de nós do caule (NN), número de racemos (NR), massa de 100 grãos (M100), número de frutos (NF) e número de sementes (NS). O experimento foi instalado no município de Bariri, SP, no ano agrícola 2007/2008. Foram avaliados 29 híbridos de mamona mais os híbridos comerciais Sara e Lyra como testemunha, conduzido em blocos ao acaso com 4 repetições. Foram realizadas as análises de variância individuais e conjuntas para cada característica avaliada. As avaliações realizadas no período de safra com relação a características produtividade de grãos e teor de óleo, verificaram que os híbridos 16 e 21 foram os mais produtivos, com médias de 1452,8 kg.ha-1 e 1347,0 kg.ha-1, respectivamente, e os híbridos 16, 15, 11, 27, 10, 5, 28, 29, 2, 9, 20, 30 e 3 apresentaram rendimentos médios superiores à média geral. A média geral de teor de óleo no período da safra foi de 40% para os 32 híbridos estudados. O híbrido 21 destacou-se tanto em teor de óleo (45,52 %), apresentando maior valor, quanto em produtividade de grãos (1347,0 kg.ha-1) segundo maior valor. Para a época de safrinha, concluiu-se que os híbridos 30, 14, 25, 12, 27, 18, 16, 26, 11, 5, 17, 31, 23 e 32, obtiveram rendimentos superiores a média geral. O híbrido testemunha 30 apresentou a maior produtividade (1272,6 kg.ha-1) e apresentou o terceiro maior valor de teor de óleo (43,65%). A média geral foi de 39,03% para teor de óleo. Verificou-se que o híbrido 21 foi o que apresentou... / The objective of this study was to evaluate the performance of castor bean new hybrids during the main harvest and the second harvest with regard to the following characteristics: grain yield (PG), average height of the plant (AP), seed oil content (TO), stem diameter, (DC), height of insertion of the primary raceme (height of the stem, AC), number of stem nodes (NN), number of raceme (NR), mass weight of 100 grains (M100), number of fruits (NF) and of seeds number (NS). The experiment was done in Bariri, Sao Paulo (SP), during the agricultural year 2007/2008, and it was evaluated 29 castor bean hybrids as well as the commercial castor bean hybrids, Sahara and Lyra, as control; the experiment was carried out randomly in blocks and tested with four replications. It was analyzed individual and joint variances for each feature assessed. The evaluations were performed taking into account the harvest season with respect to grain yield and oil content; it was found that the hybrids 16 and 21 were the most productive ones, with averages of 1452.8 kg ha-1 and of 1347.0 kg ha-1, respectively, and the hybrids 16, 15, 11, 27, 10, 5, 28, 29, 2, 9, 20, 30 and 3 had an average yield above the overall average. The overall average of oil content during the harvest period was 40% for the 32 hybrids studied. The hybrid 21 revealed more prominent among the other hybrids in regard to both oil content (45.52%), with higher value, as to grain yield (1347.0 kg ha-1), the second largest value. During the second harvest, it was found that the hybrids 30, 14, 25, 12, 27, 18, 16, 26, 11, 5, 17, 31, 23 and 32, had yields above the overall average. The control hybrid 30 had the highest yield (1272.6 kg ha-1) and had the third highest amount of oil content (43.65%). The overall average was 39.0% for oil content. It was found... (Complete abstract click electronic access below)

The southern region of Mozambique is characterized by arid to semi-arid climatic conditions with soils of poor fertility and low water retention capacity. The rainfall season is from September to April. In some areas, the rain season accommodates two production cycles, which is augmented by extended or unexpected rains in May and June. Maize is the main crop in this region. The major limiting factors for maize production in the Chókwè District under rainfed agriculture are rainfall amount and its distribution and soil fertility. Water productivity in this region is very low. The Challenge Program on Water and Food (CPWF), for which the slogan was “more crop per drop”, has attempted to identify and address water productivity constraints throughout the Limpopo River Basin (LRB). This study considers the water productivity in dryland areas, assuming that yields may not be only limited by water, but also by soil fertility. The study was aimed at investigating the improvement of water productivity by correcting nutrient deficiencies and recommending strategies to mitigate these deficiencies. A field experiment was conducted at Chókwè Agrarian Research Centre with maize cultivar (cv. Matuba). Matuba was selected because of its high tolerance to drought. Treatments were based on the most limiting soil nutrients at the experimental site. Crop parameters measured included total dry matter, fractional interception of photosynthetically active radiation (FIPAR), leaf area and grain yield. In addition, the Soil Water Balance (SWB) model was used to simulate potential yields with no nutrient limitations. Results of this study illustrated that the application of N resulted in improvements in total dry matter yield, leaf area index (LAI), FIPAR and water use efficiency (WUE). Application of both N and P improved the grain yield, leaf area duration (LAD) and WUE. SWB model simulations indicate that in only 1 out of 5 years in Chókwè District, the simulated yields were not higher compared to actual yields (0.2 - 1 ton ha-1). In conclusion, grain yield improvements are expected if nutrition is kept at optimum levels. This implies that in most years dryland yields are in fact nutrient limited and better nutrition can be used as a strategy to improve water productivity (WP) and grain yield / Dissertation (MSc Agric)--University of Pretoria, 2011. / gm2014 / Plant Production and Soil Science / unrestricted