The influence of variable amounts of irrigation water and nitrogen fertilizer and their interaction on the development, growth, grain yield and nitrogen uptake of grain sorghum were studied under monocrop (May 21 planting) and simulated double crop (July 1 planting) in the 1985 growing season and under monocrop in the 1986 growing season. Six grain sorghum hybrids, three of which had a higher grain yielding ability and the other three with a lower grain in yielding ability, were used in this study conducted at the University of Arizona, Marana Agricultural Center. All six hybrids were grown under two planting dates (May 21, July 1), two levels of irrigation water (dry, wet), and two levels of nitrogen fertilizer (0, 112 kg N/ha) in the 1985 growing season. In the 1986 growing season, two hybrids were grown under three levels of irrigation water (dry, medium, and wet) and three levels of nitrogen fertilizer (0, 84, 168 kg N/ha). Planting on May 21 (monocrop) had more days to 50% bloom, leaf area, heads number, grain yield and total dry weight than the July 1 planting (double crop). However, planting on July 1 produced a longer head exsertion (peduncle length) compared to May 21 planting. Head length, plant height, 500 seed weight, and grain volume-weight were not affected by planting date. Water stress reduced head exsertion, head length, plant height, head number, 500 seed weight, grain yield and total dry matter. However, numbers of days to 50% bloom were increased by dry treatment. Leaf area and grain volume-weight were not significantly affected by water levels. Under the conditions of this study, nitrogen fertilizer rates did not produce an effect on most of the agronomic characteristics of grain sorghum hybrids studied in this experiment. However, increased nitrogen fertilizer rates increased the uptake and nitrogen concentration in all growth stages of hybrids in the 1986 growing season.

A two-year fertilizer study on a mature vineyard of Vita vinifera, C. V. Cabernet Sauvignon and Sauvignon blanc, has been conducted on White House sandy loam (fine, mixed, thermic Ustollic Haplargid), at Page Ranch, International Agricultural Center. Furthermore, eleven different varieties grown at Page Ranch and treated with different levels of nitrogen fertilizer were tested for total P content in plant tissue and NO₃-N. Moreover, in another site with similar soil, a Cabernet Sauvignon grown at the Vina Sonoita Vineyard was treated with both soil and foliar applications of P fertilizer, and was tested for total P content in plant tissue. Soil phosphorus (P) fractions of the White House soil were determined in order to evaluate the various forms of soil P and determine the most important form which contributes most to the availability index. The objectives of this study were to study the various inorganic P forms of White House soil, compare two methods of extracting available P (Olsen and Bray P.), and examine the relationships between soil pH, extractable Al, Fe, Mn, and Zn with the availability index of soil P. Furthermore, the effect of P rates and placement on the P status of plant tissue, grape yield, wine quality and petiole-P to blade-P ratio had been investigated. Three different placements of surface, 25 and 50 cm depth at rates of 88 g of P and 80 g of N per vine, were in RCB design in 1987. In 1988, three P rates of 0, 88, and 176 g of P and 207.5 g N per vine, and the two mentioned varieties CS and SB were arranged in RCB design with factorial type. The results showed that placements did not have a significant effect of P status in plant tissue and grape yield. Yet grapes showed a significant response to P fertilizer in terms of increasing P content in plant tissues and grape yield. Petiole P to Blade P ratios were calculated for the CS, and SB grown at Page Ranch, as well as for CS grown at Sonoita vineyard. This ratio is a good indicator for diagnosis of P status in a given vineyard. Nitrogen stress had its clear and profound effect on P content of grape petioles.

Jojoba cuttings were fertilized during rooting under mist. Rooted cuttings were evaluated for growth and element concentrations. Also investigated were: CO₂ exchange during rooting; media, light and nutrition effects on nursery growth; and nutrition effects on field establishment. Fertilizer formulations used were: Peter's soluble, Osmocote, IBDU, and SCU. Rooting was depressed at 5.46 kg m⁻³ IBDU. High rates of either Osmocote or Peter's increased root weights over controls in spring. Osmocote-treated cuttings were greater than controls in nodes, fresh weight and succulence. Initial leaf concentrations of N, P and K were lower in spring than in summer and greater at lining-out for fertilized cuttings. Leaf N and K were positively related to root and shoot growth in spring and to shoot growth in summer. Leaf Zn was positively related to shoot and root growth in spring. Treatment differences in leaf element concentrations vanished after 3 months in the nursery. Differences in growth persisted for up to six months. Fertilization during rooting did not effect CO₂ exchange processes. Apparent photosynthesis (AP) declined until rooting and then rose with root growth as did root respiration. Dark respiration (Rd) dropped to a stable rate and did not increase as fast as AP upon rooting. During rooting AP, Rd and leaf succulence were well correlated. New nodes for liners grown in media with air porosities of 18.5 and 27.6 percent were equivalent. Nodes, fresh and dry weight, leaf area and specific leaf weight were greater for sun-grown than for 50 percent shade-grown liners. Shade-grown liners were more succulent. Plants grown in Osmocote amended media produced more nodes, leaves and flowers than did controls. Plants unfertilized during rooting grew fastest when grown with Osmocote in the nursery media, but were smaller at 3 months than plants fertilized during roots. Field survival after five months was not significantly affected by nutritional treatments. Growth after transplanting was significantly greater for plants fertilized in the nursery. Rooting stage fertilization is beneficial if plants are not held too long in the nursery. Nursery stage nutrition is very important for good stand establishment and growth of jojoba transplants.

The yield, fruiting habits, plant nitrogen uptake, dry matter production, and boll and fiber properties were studied in relation to nitrogen fertilizer and water application rate interactions in trickle-irrigated cotton. Nitrogen applications did not significantly increase yields because of high initial soil nitrogen and nitrogen added with the irrigation water. Significant yield differences did exist between the 60% consumption use (CU) irrigation level and the 90% and 120% CU irrigation levels. The 60% CU level resulted in appreciable plant water stress and appreciably lower yields. Nitrogen additions significantly increased seasonal plant petiole NO₃-N values as well as the number of flowers produced during the growing season. Increased water application rate lengthened the periods of peak flowering and peak boll production but had no effect on petiole NO₃-N. Increased water application rate did not significantly increase boll production, but an increasing trend of increased boll production with increasing water application rates was evident. Nitrogen applications did not significantly increase boll production, but percent boll set for the control treatment was higher. Both nitrogen additions and increased water application rates increased plant nitrogen uptake, which ranged from 163 kg N/ha to 242 kg N/ha for the water levels and 188 kg N/ha to 220 kg N/ha for the nitrogen treatments. Increased water application rates significantly increased dry matter production during the growing season. Nitrogen and water application rates affected only a few boll and fiber properties. Average boll size was increased significantly with increasing water application rates. This partially accounted for the higher yield observed at the higher irrigation levels.

No description available.

No description available.

Vita. / Digitized by Kansas Correctional Industries

Orientador: Magali Leonel / Banca: Adalton Mazeti Fernandes / Banca: Thaís Paes Rodrigues dos Santos / Banca: Emerson Loli Garcia / Banca: Anna Claudia Sahade Brunatti Abrão / Resumo: O Brasil tem o agronegócio como base da sua economia, devido às características de clima, solo, disponibilidade de água e de áreas. Uma das culturas de maior importância econômica e social para o país é a mandioca, a qual apresenta aspectos de grande importância como alimento e, também, como matéria - prima industrial. A mandioca é cultivada em todos os estados brasileiros e apresenta-se como a segunda maior fonte de amido comercial no país. O amido tem um mercado bastante diversificado e de elevado valor econômico, o que faz com que a busca por amidos com características específicas para atender este setor em constante inovação seja contínua. Um aspecto determinante no cultivo da mandioca, objetivando a obtenção de amidos com características diversas, é o estabelecimento de técnicas de cultivo que proporcionem não somente elevados rendimentos em produtividade de amido, mas também, que possam proporcionar a ampliação de usos desses amidos. Considerando que para fins industriais a mandioca permanece no campo por até 24 meses, e que a nutrição mineral adequada da planta é um dos fatores essenciais para aumentar o crescimento e o acúmulo de massa seca, a compreensão da interferência da fase de desenvolvimento da planta e das condições de cultivo torna-se essencial para a geração de informações determinantes para a produção de amidos nativos de mandioca com propriedades diferenciadas. Diante da importância do fósforo na maioria das transformações energéticas dos processos vitais ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Brazil, has agribusiness as the basis of its economy, due to the characteristics of climate, soil, availability of water and areas. One of the most important economic and social crops for the country is cassava, which presents aspects of great importance as food and also as an industrial raw material. Cassava is grown in all Brazilian states and is the second largest source of commercial starch in the country. The starch has a very diversified market and of high economic value, which makes that the search for starches with specific characteristics to serve this sector in constant innovation is continuous. A determinant aspect in the cultivation of cassava in order to obtain starches with different characteristics is the establishment of cultivation techniques that provide not only high yields of starch / hectare, but also, that can provide the amplification of uses of these starches. Considering that for industrial purposes cassava remains in the field for up to 24 months and that adequate mineral nutrition of the plant is one of the essential factors to increase the growth of the plant and the accumulation of dry water; the understanding of the interference of the development stage of the plant and the conditions of cultivation becomes essential for the generation of information determinant for the production of native starches of cassava with differentiated properties. Faced with the fundamental importance of phosphorus in most of the energy transformations of the vital processes of plants, as well as in the synthesis of starch and in the technological properties of this carbohydrate; The objective of this work was to evaluate the interferences of the stage of development of the cassava plant and the level of phosphate fertilization on the characteristics of form and size of starch granules, X-ray diffraction pattern, crystallinity, amylose content, phosphorus content, swelling power, solubility, ... / Doutor

Digitized by Kansas Correctional Industries

Digitized by Kansas Correctional Industries