No description available.

A field experiment was conducted on a Casa Grande sandy loam at the Maricopa Agricultural Center to 1) determine the optimum rates of late season N needed to achieve optimum yield and quality of irrigated dumm wheat in conjunction with varying rates of early season N, and 2) to evaluate the usefulness of stem NO₃⁻N analysis in predicting the late season N rates which optimize grain production but minimize the potential for nitrate pollution of groundwater. The application of 80, 195 and 350 lbs. N/a during vegetative growth resulted in wheat with deficient, sufficient and excessive N status at the boot stage as indicated by stem NO₃⁻N analysis. The application of 60 lbs. N/a at heading to N-deficient wheat and 15 lbs. N/a to N-sufficient wheat resulted in grain protein levels above 14% but had little effect on grain yield. Applications of N at heading to wheat which had previously received excessive N did not affect grain yield or quality. The use of stem NO₃⁻N analysis appears to be a useful tool in predicting the minimum N rate to be applied during the early reproductive period to insure acceptable levels of grain protein at harvest.

Seeding rates of wheat and barley varying from 50 to 250 pounds per acre were planted at four or five planting dates from the 1987-88 season to the 1989-90 season. Optimum seeding rates for wheat seemed to be near the upper limit whereas for barley it fell between 150 and 250 pounds per acre. This is considerably higher than what is commonly recommended in other parts of the state.

Canarygrass (Phalaris minor) has become an increasingly widespread weed in wheat grown in central and southwestern Arizona. Only two herbicides, Barban and Diclofop, have been used effectively to control this weed. The registration of Barban was dropped in 1989 and the labeled rate of Diclofop was lowered to marginal control levels in 1990. A test was conducted to evaluate potential new treatments for the control of canarygrass. One treatment; Puma at 1.14 lbs./A resulted in excellent control of this weed.

Four irrigation scheduling methods are compared over a three year period on the Safford Agricultural Center. A computerized checkbook method based on the consumptive water use curves of Erie, et al, updated with near real time evapotranspiration data from the AZMET system and utilizing empirical crop coefficients, produced the highest yields and with the highest water use efficiency. Scheduling irrigations with the IR thermometer produced yields higher than the Check when a Stress Index threshold of 2 (similar to a CWSI of 0.2) was used, but not with a threshold value of 3 nor 4. A method of irrigation scheduling using Erie's curves, but not updated for current weather values, yielded less than the check in all years of the study, and was not considered an acceptable method Irrigation inputs from the 1990 season were plugged into new near real time irrigation scheduling software which utilizes AZMET data to determine both evapotranspiration and crop coefficients. This method was found to track the field data quite well and will be utilized in future research.

Durum wheat (Triticum turgidum L. var. durum ) is grown as a winter annual crop, normally in rotation with cotton, and in 1989, comprised 121,500 acres in Arizona. Winter rainfall is insignificant, therefore water is supplied totally through surface irrigation. The relationship between the timing and amount of irrigation water applied and grain yields have not been well -defined Field plot studies were conducted in 1986 and 1987 to test the feasibility of using the Crop Water Stress Index (CWSI) to time wheat irrigations and also to determine the relationship among the CWSI, grain production, and water applied The study was repeated at the commercial production level with a grower cooperator in 1989 to determine the usefulness of CWSI scheduling on large farms. Highest grain production was attained when irrigations were scheduled when the CWSI averaged 0.37 and 0.30 units on small plots for 1986 and 1987, respectively. At the grower production level, highest yields were attained when irrigations were scheduled when the CWSI averaged 0.17 units. In 1986 and 1987 scheduling irrigations at lower CWSI values did not significantly increase grain production while requiring more applied water than the optimum CWSI values. Scheduling irrigations at CWSI's exceeding the optimum values did significantly reduce grain production from the optimum, but required less applied water in all three years.

Made available in DSpace on 2014-06-11T19:24:45Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-08-04Bitstream added on 2014-06-13T18:52:36Z : No. of bitstreams: 1 gomes_a_me_botfca.pdf: 192281 bytes, checksum: 3403a5d364ee53a8f4d39f93d481cb3e (MD5) / Os custos de produção na agricultura determinam o nível de rentabilidade econômica das atividades agrícolas desenvolvidas na propriedade rural, o que permite avaliar a eficiência do sistema de produção adotado pelo produtor ou empresário rural. O objetivo deste trabalho foi analisar e comparar economicamente as culturas de feijão, soja e milho em sistemas de produção irrigados e não irrigados. Os dados foram coletados em quatro propriedades rurais localizadas no município de Itaí, pertencente ao EDR de Avaré, região sudoeste do Estado de São Paulo, na safra 2005/06, no período de agosto de 2005 à julho de 2006. A partir desses dados foram estimados o custo operacional efetivo e o custo operacional total. Para análise da rentabilidade foram determinados os indicadores econômicos denominados de receita bruta, margem bruta, ponto de nivelamento, preço de equilíbrio, lucro operacional e índice de lucratividade. Partiu-se do pressuposto que o sistema de produção irrigado deveria apresentar o maior nível de produtividade e rentabilidade, entretanto os dados demonstraram que nas culturas de feijão e milho no sistema irrigado os resultados foram inferiores ao sistema não irrigado. A produtividade média do feijão não irrigado foi 29% superior e o índice de lucratividade médio foram 26% superior ao sistema irrigado. A soja irrigada apresentou produtividade e receita bruta média 19% superior ao sistema não irrigado, porém a cultura apresentou prejuízo nos dois sistemas, devido ao baixo preço de venda obtido pelo produtor. Em relação à combinação das culturas de feijão das águas e soja de verão e feijão das águas e milho safrinha, a sucessão feijão e milho não 2 irrigados, apresentaram a maior rentabilidade com índice de lucratividade de 45,26%, em 2° lugar irrigados, apresentaram a maior rentabilidade com índice de lucratividade de 45,26%, em... / The costs of production in the agriculture determine the level of economical profitability of the agricultural activities developed in the rural property, which allows evaluating the efficiency of the system of production adopted by the producer or rural businessman. The objective of this work is to analyze and compare economically the cultures of bean, soy and corn in systems of production irrigated or not. The data were collected in four farms located in Itaí, pertaining to the EDR of Avaré, south-west region of the State of Sao Paulo, in the harvest 2005/06, in the period of August of 2005 to the July of 2006. From these data were estimated the effective operational cost and the total operational cost. For the analysis of the profitability were determined the economic indicators of gross revenue, gross margin, break even point, balance price, operational profit and profitability rate (IL). It proceeded from the assumption that the system of production irrigated should present nigher productivity and profitability. From data it was observed that the bean and corn cultures under irrigated system the results were lower than the not irrigated system. The average productivity of the not irrigated bean was 29 % superior and the average rate of profitability was 26% superior to the irrigated system. The irrigated soy presented productivity and gross average profit 19% superior to the not irrigated system, however the culture presented loss in two systems, due to the low obtained sale price. Regarding to combination of the cultures of water bean, summer soy and corn safrinha, the succession bean and corn not irrigated,presented the biggest profitability with rate of profitability of 45,26 %, folowed by the bean and corn irrigated with 18,93 %, in 3rd place the bean and soy not irrigated with 6,67 % and at last the bean and soy irrigated at a loss of 7,35 %... (Complete abstract, click electronic access below)

Orientador: Silvio José Bicudo / Banca: Maura Seiko T. Esperancini / Banca: Ricardo Augusto Dias Kanthack / Resumo: Os custos de produção na agricultura determinam o nível de rentabilidade econômica das atividades agrícolas desenvolvidas na propriedade rural, o que permite avaliar a eficiência do sistema de produção adotado pelo produtor ou empresário rural. O objetivo deste trabalho foi analisar e comparar economicamente as culturas de feijão, soja e milho em sistemas de produção irrigados e não irrigados. Os dados foram coletados em quatro propriedades rurais localizadas no município de Itaí, pertencente ao EDR de Avaré, região sudoeste do Estado de São Paulo, na safra 2005/06, no período de agosto de 2005 à julho de 2006. A partir desses dados foram estimados o custo operacional efetivo e o custo operacional total. Para análise da rentabilidade foram determinados os indicadores econômicos denominados de receita bruta, margem bruta, ponto de nivelamento, preço de equilíbrio, lucro operacional e índice de lucratividade. Partiu-se do pressuposto que o sistema de produção irrigado deveria apresentar o maior nível de produtividade e rentabilidade, entretanto os dados demonstraram que nas culturas de feijão e milho no sistema irrigado os resultados foram inferiores ao sistema não irrigado. A produtividade média do feijão não irrigado foi 29% superior e o índice de lucratividade médio foram 26% superior ao sistema irrigado. A soja irrigada apresentou produtividade e receita bruta média 19% superior ao sistema não irrigado, porém a cultura apresentou prejuízo nos dois sistemas, devido ao baixo preço de venda obtido pelo produtor. Em relação à combinação das culturas de feijão das águas e soja de verão e feijão das águas e milho safrinha, a sucessão feijão e milho não 2 irrigados, apresentaram a maior rentabilidade com índice de lucratividade de 45,26%, em 2° lugar irrigados, apresentaram a maior rentabilidade com índice de lucratividade de 45,26%, em... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The costs of production in the agriculture determine the level of economical profitability of the agricultural activities developed in the rural property, which allows evaluating the efficiency of the system of production adopted by the producer or rural businessman. The objective of this work is to analyze and compare economically the cultures of bean, soy and corn in systems of production irrigated or not. The data were collected in four farms located in Itaí, pertaining to the EDR of Avaré, south-west region of the State of Sao Paulo, in the harvest 2005/06, in the period of August of 2005 to the July of 2006. From these data were estimated the effective operational cost and the total operational cost. For the analysis of the profitability were determined the economic indicators of gross revenue, gross margin, break even point, balance price, operational profit and profitability rate (IL). It proceeded from the assumption that the system of production irrigated should present nigher productivity and profitability. From data it was observed that the bean and corn cultures under irrigated system the results were lower than the not irrigated system. The average productivity of the not irrigated bean was 29 % superior and the average rate of profitability was 26% superior to the irrigated system. The irrigated soy presented productivity and gross average profit 19% superior to the not irrigated system, however the culture presented loss in two systems, due to the low obtained sale price. Regarding to combination of the cultures of water bean, summer soy and corn safrinha, the succession bean and corn not irrigated,presented the biggest profitability with rate of profitability of 45,26 %, folowed by the bean and corn irrigated with 18,93 %, in 3rd place the bean and soy not irrigated with 6,67 % and at last the bean and soy irrigated at a loss of 7,35 %... (Complete abstract, click electronic access below) / Mestre