The last irrigation of wheat can be applied at the soft dough stage or for a sandy loam soil according to crop water use calculations. The purpose of this study is to verify at what stage the last irrigation of wheat should be applied. Studies were conducted on 7 commercial fields where the last irrigation was applied at the soft dough stage or about 10 to 14 days after soft dough. Applying the final irrigation after the soft dough stage does not appear to increase yield on average according to the results of this study.

A study was done on durum wheat and barley to determine the economical consequences of irrigation scheduling. Delays of 3 days and 7 days were applied after AZSCHED software called for irrigations to similate a wait for water from the irrigation canal. Yields were reduced by the delays, but with the crop values reduced by the cost of irrigation no money was lost in delaying irrigations on the durum wheat and $8-9 per acre was lost on the barley.

A field study was conducted for two years in three semi-arid regions of Syria in order to define, under field conditions, the wheat (Triticum aestivum L.) yield response function to irrigation water salinity and to study the process of soil salt accumulation. The three regions experience similar climatic conditions (semi-arid Mediterranean climate) but have different soil textures, varying from sandy loam to clay. The study involved 74 farms all of which had been irrigating for more than 3 years prior to this study, with well water of different salinity values (0.44 to 14.1 dS/m). All of these farms operated with similar cultural practices. / Results indicate that the wheat yield response function to irrigation water salinity differs between the three regions. The irrigation water threshold salinity value beyond which wheat yield started to decline, was found to be 6.5 dS/m, 3.5 dS/m and 1.2 dS/m in the Khabur low plains; Aleppo south plains and Shedadeh area respectively. Wheat was more salt tolerant to irrigation water salinity in sandy loam soils than clay loam soils. The three threshold values obtained in this study are different from the "universal" value of 4 dS/m which is proposed in current literature. The "universal" value was obtained from artificially salinized field plots seeded under non-saline conditions. / In addition, it was found that salt accumulation in the soil profile increases as soil clay content increases. / The results demonstrate the necessity of establishing regional water quality criteria when planning the use of saline water sources for irrigation in semi-arid regions.

Made available in DSpace on 2014-06-11T19:32:43Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-01-28Bitstream added on 2014-06-13T20:23:54Z : No. of bitstreams: 1 oliveira_la_dr_botfca.pdf: 1868550 bytes, checksum: 015aee7eda860c293d1c4629b6294c11 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Universidade Estadual Paulista (UNESP) / Foram conduzidos dois experimentos: I. em vasos construídos com anéis de PVC, de diâmetro nominal de 0,15m e altura de 0,07m, unidos para proporcionar quatro alturas: 0,21 m, 0,35 m, 0,49 m e 0,63 m, correspondendo aos seguintes níveis freáticos: 0,17 m, 0,31 m, 0,45 m e 0,59 m de profundidade, a fim de estudar seus efeitos na produção de matéria seca e evapotranspiração real em cinco cultivares de trigo, IAC 24, IAC 350, IAC 364, IAC 375 e BR 18. No experimento II, utilizaram-se vasos plásticos de cor preta com capacidade de cinco kg de solo, com objetivo de avaliar os efeitos de quatro níveis de potencial mínimo de água no solo: Capilaridade (CC), - 0,035 MPa, - 0,070 MPa, -1,50 MPa para as mesmas variáveis e variedades. Foi utilizado o delineamento experimental em blocos casualizados nos dois experimentos, com três repetições, totalizando 60 parcelas em cada um. Os experimentos I e II foram instalados em ambientes protegidos e condições diferentes, e permitiram inferir as seguintes conclusões: Os tratamentos intermediários do Experimento I (profundidades de lençol 0,31 m e 0,45 m) mostraram tendência de maiores perdas de água que os de 0,17 m e 0,59 m. Houve também maiores valores para os teores relativos de água (TRA) nos tratamentos intermediários e as cultivares BR 18 e IAC 375 tiveram maiores TRA para todos os tratamentos, evidenciando terem tendência a maior tolerância à seca para as mesmas condições de umidade do solo. No Experimento I, a produção de matéria seca da parte aérea e 2 de grãos foi mais elevada na cultivar BR -18 em relação as IAC - 24 e IAC - 364 e semelhante as IAC - 350 e IAC - 375. Os tratamentos 0,31 m e 0,45 m mostraram maior produção para as duas variáveis citadas em relação aos tratamentos 0,17 m e 0,59 m. Não houve diferença estatística entre os tratamentos e os cultivares para matéria seca das raízes, apenas para... / Two experiments were conducted: I. in pots built with PVC rings, with nominal diameter of 0.15 m and height of 0. 07 m, attached to provide four heights: 0.21 m, 0.35 m, 0.49 m and 0.63 m, corresponding to the following water level depths: 0.17 m, 0.31 m, 0.45 m and 0,59m, in order to study their effects on dry matter production and real evapotranspiration in five varieties of wheat, IAC 24, IAC 350, IAC 364, IAC 375 and BR18. In the experiment II , were used black colored plastic pots with five kilograms of soil capacity, to evaluate effects of four minimum soil water potential levels: Capillarity (CC), -0,035 MPa, -0,070 MPa and -1.50 MPa for the same variables and varieties. It was used a block experimental design randomized in the two experiments, with three repetitions. The experiments I and II have been installed in different protected environments and allowed infering the following conclusions: The experiment I, intermediary treatments (0.31 m and 0.45 m) showed trend to a greater water loss than 0.17 m and 0.59 m. There were also greater values for relative water content (RWC) in intermediary treatments, and varieties BR - 18 and IAC - 375 had larger RWC for all processing, showing a tendency to a greater tolerance to drought; In experiment I, the dry matter production from air part and grain was higher in varietie IAC - 18 comparing to the varieties IAC - 24 and IAC - 364 and similar to the IAC - 350 and IAC - 375. The treatments 0.31 m and 0.45 m showed greater productionfor the two variables listed before for treatments 0,17 m and 0,59 m. There was no statistical difference among treatments and crops related to the dry matter of roots, only in water depth 0.31 m, the BR - 18 stood out with larger values comparing to the others. In experiment II, treatments with greater minimum water potentials showed the greatest evapotranspiration values, considering in order of decreasing... (Complete abstract click electronic access below)

Orientador: Antônio Evaldo Klar / Banca: João Carlos Cury Saad / Banca: Dinival Martins / Banca: Maria Fraga Soares Muçouçah / Banca: Helton Rogério Mazzer / Resumo: Foram conduzidos dois experimentos: I. em vasos construídos com anéis de PVC, de diâmetro nominal de 0,15m e altura de 0,07m, unidos para proporcionar quatro alturas: 0,21 m, 0,35 m, 0,49 m e 0,63 m, correspondendo aos seguintes níveis freáticos: 0,17 m, 0,31 m, 0,45 m e 0,59 m de profundidade, a fim de estudar seus efeitos na produção de matéria seca e evapotranspiração real em cinco cultivares de trigo, IAC 24, IAC 350, IAC 364, IAC 375 e BR 18. No experimento II, utilizaram-se vasos plásticos de cor preta com capacidade de cinco kg de solo, com objetivo de avaliar os efeitos de quatro níveis de potencial mínimo de água no solo: Capilaridade (CC), - 0,035 MPa, - 0,070 MPa, -1,50 MPa para as mesmas variáveis e variedades. Foi utilizado o delineamento experimental em blocos casualizados nos dois experimentos, com três repetições, totalizando 60 parcelas em cada um. Os experimentos I e II foram instalados em ambientes protegidos e condições diferentes, e permitiram inferir as seguintes conclusões: Os tratamentos intermediários do Experimento I (profundidades de lençol 0,31 m e 0,45 m) mostraram tendência de maiores perdas de água que os de 0,17 m e 0,59 m. Houve também maiores valores para os teores relativos de água (TRA) nos tratamentos intermediários e as cultivares BR 18 e IAC 375 tiveram maiores TRA para todos os tratamentos, evidenciando terem tendência a maior tolerância à seca para as mesmas condições de umidade do solo. No Experimento I, a produção de matéria seca da parte aérea e 2 de grãos foi mais elevada na cultivar BR -18 em relação as IAC - 24 e IAC - 364 e semelhante as IAC - 350 e IAC - 375. Os tratamentos 0,31 m e 0,45 m mostraram maior produção para as duas variáveis citadas em relação aos tratamentos 0,17 m e 0,59 m. Não houve diferença estatística entre os tratamentos e os cultivares para matéria seca das raízes, apenas para... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Two experiments were conducted: I. in pots built with PVC rings, with nominal diameter of 0.15 m and height of 0. 07 m, attached to provide four heights: 0.21 m, 0.35 m, 0.49 m and 0.63 m, corresponding to the following water level depths: 0.17 m, 0.31 m, 0.45 m and 0,59m, in order to study their effects on dry matter production and real evapotranspiration in five varieties of wheat, IAC 24, IAC 350, IAC 364, IAC 375 and BR18. In the experiment II , were used black colored plastic pots with five kilograms of soil capacity, to evaluate effects of four minimum soil water potential levels: Capillarity (CC), -0,035 MPa, -0,070 MPa and -1.50 MPa for the same variables and varieties. It was used a block experimental design randomized in the two experiments, with three repetitions. The experiments I and II have been installed in different protected environments and allowed infering the following conclusions: The experiment I, intermediary treatments (0.31 m and 0.45 m) showed trend to a greater water loss than 0.17 m and 0.59 m. There were also greater values for relative water content (RWC) in intermediary treatments, and varieties BR - 18 and IAC - 375 had larger RWC for all processing, showing a tendency to a greater tolerance to drought; In experiment I, the dry matter production from air part and grain was higher in varietie IAC - 18 comparing to the varieties IAC - 24 and IAC - 364 and similar to the IAC - 350 and IAC - 375. The treatments 0.31 m and 0.45 m showed greater productionfor the two variables listed before for treatments 0,17 m and 0,59 m. There was no statistical difference among treatments and crops related to the dry matter of roots, only in water depth 0.31 m, the BR - 18 stood out with larger values comparing to the others. In experiment II, treatments with greater minimum water potentials showed the greatest evapotranspiration values, considering in order of decreasing... (Complete abstract click electronic access below) / Doutor

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Call number: LD2668 .T4 1985 M49 / Master of Science

Wheat irrigations were scheduled using two computer models and an infrared thermometer using two critical threshold values. Yields from these plots were compared with plots scheduled by the farm manager. The highest yield was obtained by the computer model using evapotranspiration data taken from the local AZMET station; the plots scheduled by the infrared thermometer (using the low threshold value) ranked a close second.

Thesis (M.Sc. (Agronomy)) --University of Limpopo, 2013 / In South Africa, wheat ranks first among the winter cereal crops produced and plays an important role in the country’s economy. The study was conducted to evaluate different South African wheat cultivars under irrigation for quality and yield parameters in Limpopo province. A field experiment was conducted during 2011 winter growing season under irrigation at the University of Limpopo experimental farm (Syferkuil). Eight wheat cultivars namely: Olifants, CNR 826, SST 347, Baviaans, Duzi, Steenbrass, SST 356 and Krokodil were laid out in a randomized complete block design with four replications for evaluation of yield and quality. The results showed that the highest grain yield obtained was 2372 kg/ha by CNR 826, and the lowest 311 kg/ha by SST 347. Flour yield, break flour yield, flour protein and mixogram development time and water absorption were not significantly different among cultivars. The highest hectolitre mass was 75.13 kghl-1for CNR 826 and the lowest 72.20 kghl-1 for Olifants. The highest falling number obtained was 187.00 sec for SST 347 and the lowest was 81.50 sec for Steenbrass. Cultivars CNR 826, SST 347, Steenbrass and SST 356 showed a good potential on protein content but Krokodil, Olifants and Baviaans had poor protein contents at 9.63%, 9.73% and 10.24% respectively. These results showed that wheat cultivars evaluated were within the requirements of the grading systems of South Africa as regards hectolitre mass and protein content. All these cultivars did not reach the required grade of 220 seconds in falling numbers with Olifants (97.50 sec), CNR 826 (103.50 sec), SST 347 (187.00 sec), Baviaans (146.75 sec), Krokodil (139.50 sec), Steenbrass (81.50 sec) and Duzi (50.25 sec), but only SST 356 met the requirement for utility grade with164.50 seconds. Olifants, CNR 826, Krokodil and Steenbrass yielded above 1500 kgha-1thus showing good potential under Limpopo conditions. These cultivars could be included in future performance evaluations in Limpopo.

Wastewater has become a vital new supply for irrigation; however, concerns are mounting about environmental and health hazards related to heavy metals present in wastewater. Experiments were conducted to evaluate wheat ( Triticum aestivum L.) and buckwheat (Fagopyrum esculentum L.) uptake of copper (Cu) and zinc (Zn). / Some 15 plants per pot were allowed to establish themselves in the greenhouse for 4 and 6 weeks for buckwheat and wheat, respectively. Plants were then transferred to one of two growth chambers differing in the vapor pressure deficit (VPD), creating conditions for two different transpiration rates to occur: high (HT) and low (LT). A total 48 pots for each crop were seeded in order to evaluate the effect of 8 treatment combinations of Cu and Zn (0/0, 5/0, 15/0, 30/0, 0/25, 5/25, 15/25, 30/25) levels (mg L-1). Treatments were laid out in a completely randomized design within each growth chamber. / Three plants were harvested from each pot at days 10 and 20 for wheat, and days 6, 12 and 18 days for buckwheat to measure dry mass and Cu and Zn content in different plant parts. Heavy metal treatments had no significant effect on transpiration rate for either crops. The higher transpiration rate increased Cu/Zn uptake. A Zn amendment in the absence of Cu had a beneficial effect on buckwheat growth, whereas with Cu at 15 mg Cu L-1 or 30 mg Cu L-1 the lowest dry weights were recorded, regardless of the transpiration rate. Roots contained greater concentrations of Cu and Zn, irrespective of the treatment level and transpiration rate, than did stems, leaves or grain. High retention of heavy metals in the roots of cereal crops may be desirable because these parts are not generally utilized as food or feed.