Made available in DSpace on 2014-06-11T19:23:11Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-12-07Bitstream added on 2014-06-13T19:29:12Z : No. of bitstreams: 1 guimaraes_rcm_me_jabo.pdf: 325304 bytes, checksum: 6ae2c8d955c79599921ce2ff403b90bb (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O impacto dos resíduos orgânicos agroindustriais no ambiente pode ser reduzido pelo seu uso agrícola e, do ponto de vista da fertilidade do solo, o que se deseja com a aplicação dos resíduos é aumentar o teor de matéria orgânica do solo e fornecer nutrientes para as plantas. Com este trabalho objetivou-se avaliar o efeito do lodo biológico de indústria de gelatina em atributos químicos de dois Argissolos Vermelho-Amarelos (PVA-1, arenoso e PVA-2, textura média) e de um Latossolo Vermelho (LV, argiloso) e determinar as frações de mineralização do carbono e do nitrogênio no PVA-2. Todos os experimentos foram conduzidos em condições de laboratório, em delineamento experimental inteiramente casualizado, com seis doses de lodo (0; 100; 200; 300; 400 e 500 m3 ha-1) e três repetições. Após 120 dias de incubação, o lodo biológico aumentou o valor de pH, a CTC efetiva, os teores de P, Ca, Mg, Na e N-inorgânico, diminuiu os teores de Al e H+Al e não alterou os teores de matéria orgânica dos solos. O aumento nos teores de Ca, Mg e Na foi cerca de três vezes maior do que o da CTC efetiva, o que indica que a maior parte do aumento é devido ao acúmulo de sais em solução e, por isso, há potencial para perdas por lixiviação. A fração de mineralização do carbono foi superior a 100%, indicando efeito “priming”, ao final de 193 dias de incubação. A fração de mineralização do nitrogênio em 126 dias foi superior a 74% e a meia vida média foi de 8,7 dias, indicando que o N do resíduo é rapidamente disponibilizado para as plantas / The impact of agro-industrial organic wastes in the environment can be reduced by its use in agricultural systems and from the point of view of soil fertility increasing the soil organic matter content and providing nutrients to the plants are desirable. The objective of this study was to evaluate the effect of gelatin industry biological sludge in chemical attributes of two Ultisols (S1, sand and S2, loam) and a Oxisol (S3, clay) and to determine the carbon and nitrogen mineralization fractions in S2. The experiments were carried out under laboratory conditions, in a completely randomized design with six biological sludge rates (0, 100, 200, 300, 400 and 500 m3 ha-1) and three replicates. After 120 days of incubation, the biological sludge increased the value of pH, effective cation exchange capacity (ECEC), P, Ca, Mg, Na and inorganic N contents, decreased Al and H + Al contents, and did not affect organic matter content in soils. The increase in Ca, Mg and Na contents was about three times greater than the ECEC, indicating that most of this increase is due to salts accumulation in solution and therefore there is potential for leaching losses. Carbon mineralization fraction was greater than 100%, indicating priming effect at the end of 193 days of incubation. Nitrogen mineralization fraction in 126 days was greater than 74% and the half-life averaged was 8.7 days, indicating that the nitrogen in the biological sludge is readily available to the plants

Made available in DSpace on 2014-06-11T19:23:25Z (GMT). No. of bitstreams: 0 Previous issue date: 2002-10-31Bitstream added on 2014-06-13T20:30:08Z : No. of bitstreams: 1 mello_g_me_jabo.pdf: 2739688 bytes, checksum: 743e97d30e56d74696c18863b0b97333 (MD5) / Com o objetivo de avaliar a variabilidade espacial das propriedades físicas e químicas, do potencial natural de erosão (PNE), das perdas de solo (A) e do risco de erosão (RE) em duas regiões distintas, através de análises geoestatísticas, e visando fornecer subsídios para descrição de padrões de ocorrência de fertilidade e de erosão em duas áreas intensamente cultivadas, avaliou-se a dependência espacial das seguintes variáveis químicas: P, MO, K, Ca, Mg, pH, CTC e V%; físicas: areia, silte e argila; do PNE, da A e do RE. Coletaram-se amostras de solo em duas profundidades (0-0,2 e 0,6-0,8 m) situados em malha irregular de amostragem na região de Monte Alto (SP), num Argissolo Vermelho-Amarelo (PVA), sob diferentes manejos e relevo ondulado, perfazendo 88 pontos em uma área total de 1465 ha; e na região de Jaboticabal em Latossolo Vermelho (LV) cultivado com cana-de-açúcar em relevo suave, perfazendo 128 pontos, numa área total de 2597 ha. As propriedades químicas e físicas dos solos estudados apresentaram dependência espacial, com exceção da CTC na profundidade de 0,6-0,8 m para o solo LV; Ca e argila na profundidade de 0-0,2 m, e P, MO, K, Mg, areia e argila na camada de 0,6-0,8 m no solo PVA. As variáveis químicas e físicas estudadas ajustaram-se aos modelos esférico, exponencial, e algumas apresentaram semivariograma sem estrutura definida. O solo PVA apresentou maior variabilidade espacial das propriedades químicas e físicas, principalmente na profundidade 0,6 -0,8 m, camada que sofre menor influência antrópica. O solo LV apresentou zonas mais homogêneas de fertilidade e granulometria. O solo PVA apresentou maiores RE, devido ao relevo, uso atual e manejo. Para o solo LV os riscos são menos expressivos, devido tanto ao relevo quanto à utilização de práticas de uso e manejo mais adequadas. / With the aim to evaluate spatial variability of physical and chemical soil properties, natural erosion potential (NEP), soil losses (A) and erosion risk (ER) in two distinct regions through geostatistical analysis and to provide subsidies for description fertility and erosion standards in two intensively cultivated areas, was evaluated the spatial dependence of the following chemical variables: P, organic matter (OM), K, Ca, Mg, pH, cation exchange capacity (CEC) and base saturation (BS); physical variables: sand, silt and clay; NEP, A and ER. Were collected soil samples at two depth (0-0.2 and 0.6-0.8 m) located at irregular mesh of sampling in the region of Monte Alto (SP), in an Podzolic Yellow-Red (Alfissolo) (PVA), under different management and undulated topography resulting 88 points in 1465 ha of total area; and at the region of Jaboticabal in an Red Latosol (Oxissolo) (LV) cultivated with sugar cane on a smooth topography, resulting 128 points in 2597 ha of total area. The chemical and physical soil properties studied showed spatial dependence, except CEC at 0.6-0.8 m deep for LV; Ca and clay at 0-0.2 m deep and P, OM, K, Mg, sand and clay at 0.6-0.8 m deep for PVA. The chemical and physical variables studied were adjusted to spherical and exponential models and some showed semivariogram without defined structure. The PVA showed high spatial variability of chemical and physical soil properties, mainly at 0.6-0.8 m deep, layer with less antropic influence. The LV soil showed more homogenous zones of fertility and composition granulometric. The PVA soil showed high ER, due the relief, actual use and management. For LV soil the risks are less expressive due both the relief and the utilization of appropriated use and management practices.

O eucalipto apresenta bom crescimento em solos com alta acidez trocável e ativa, sendo a calagem uma prática realizada com o objetivo de fornecer Ca2+ e Mg2+. No entanto, o seu efeito fica restrito à camada superficial do solo devido à baixa solubilidade dos constituintes neutralizantes. A aplicação de gesso agrícola promove a movimentação de Ca2+ e SO4-2 no perfil do solo, possibilitando a melhora do subsolo para favorecer o crescimento radicular. A maioria das plantações de eucalipto no Brasil é estabelecida em solos de baixa fertilidade, verificando-se respostas significativas à fertilização com o fim de garantir a sustentabilidade da produção a longo prazo. O objetivo do presente estudo foi avaliar o crescimento da parte aérea e radicular do eucalipto em resposta à fontes e métodos de aplicação de cálcio em um Neossolo Quartzarênico. Para tal fim, foram mensurados: i) os teores de cálcio, magnésio e enxofre no solo e nas folhas; ii) a densidade de raiz fina (DRF) por biomassa ao longo do perfil e a umidade no solo, e; iii) o crescimento em altura e no diâmetro à altura do peito das árvores de Eucalyptus. A fertilização com calcário dolomítico e calcário calcinado em faixa promoveu aumento nos teores de Ca2+ e Mg2+ trocáveis no solo, especialmente nas camadas superficiais. Os teores foliares de Ca, Mg, K e S encontram-se na faixa adequada nas três datas de amostragem. O volume de tronco das árvores foi superior com a aplicação do calcário dolomítico em faixa comparativamente à aplicação de calcário dolomítico em área total ou incorporado. A mistura de calcário dolomítico com a maior dose de gesso aumentou os teores Ca2+ e Mg2+ trocáveis no solo nas camadas superficiais. A aplicação de gesso aumentou expressivamente os teores de SO42- abaixo dos 40 cm de profundidade. A DRF foi superior com a ausência da aplicação das fontes de cálcio. Com a aplicação de gesso agrícola misturado com calcário dolomítico se obteve um volume de madeira similar à aplicação de calcário dolomítico. / Eucalyptus plantations have a good development in soils with high exchangeable and active acidity, therefore, being the liming an activity done with the goal of providing Ca2+ and Mg 2+. However, its effect is restricted to the surface layer due to the low solubility of neutralizing constituents. The application of gypsum promotes the movement of Ca2+ and SO4-2 in the soil profile providing a more adequate root growth. Most eucalyptus plantations in Brazil were established in soils of low fertility, verifying significant responses to fertilization in order to ensure the sustainability of long-term production. The aim of this study was to evaluate the nutrition and aerial and root growth of eucalypts in response to different sources and methods of application of calcium in a Quartzipsamment. It was measured: i) calcium, magnesium and sulfur levels in soil and leaf; ii) Fine root density along the profile and soil moisture; iii) Growth in height and DBH of E. urophylla plantation. The fertilization with dolomitic and calcitic limestone in furrows promoted an increase in Ca2+ and Mg2+ levels in the soil, especially in surface layers. The Ca2+ and Mg2+ foliar levels found in the good range in three times. The volume of eucalypts was increased with dolomitic limestone in furrows comparatively broadcasted distribution and incorporation of dolomitic limestone. The mix of dolomitic limestone and the high gypsum level increases Ca2+ and Mg2+ levels in the soil in surface layers. Gypsum increases SO42- levels below 40 cm deep. The fine root density was higher without calcium fertilization. The volume wood with gypsum more dolomitic limestone applied was similar compared with dolomitic limestone applied.

Light availability in forest understories is a well recognized constraint on sapling growth, but limitations in soil nitrogen (N) availability, and the link to foliar photosynthetic capacity, typically receive less consideration in describing stand dynamics. My primary hypothesis is that light and soil N availability have species-specific effects on photosynthetic activity and growth, and that together these resources will better define understory development in complex forests. To test these relationships, I examined 1) soil N indices and the tradeoffs between soil fertility and light attenuation in old-growth forest understories; 2) the effects of light and N constraints on understory sapling foliar N concentration (N%), N per unit area (Na), and natural abundance of ¹³C; 3) the effects of light and soil N supply on species growth and photosynthetic activity in a factorial field experiment; and 4) the mechanisms responsible for the stagnation of understory saplings. Soil N indices incorporating dissolved inorganic N and organic N were useful in characterizing differences in N supply among contrasting sites. Understory light availability declined with increasing soil N supply, while understory Abies lasiocarpa had strong correlations between foliar N% and soil N availability, despite shading effects. In partial-cut forests, understory Tsuga heterophylla and Picea glauca x sitchensis had consistent foliar N% across gradients of light availability; in contrast, foliar N% of Betula papyrifera and Thuja plicata declined with increasing shade, which would distort assessments of soil fertility and perhaps contribute to increased mortality of these species in deep shade. Strong correlations between foliar Na and ¹³C or growth increment suggest foliar N per unit area is the simplest integration of light availability and N nutrition on leaf photosynthetic activity. Ontogenic interactions that occur among foliar attributes and tree size in forest understories, especially for saplings < 1 m in height, contribute to time effects on growth patterns and emphasize the need for long-term studies of species autecology and stand dynamics. My experimental manipulation of light and N supply on saplings was ineffective, and future research using natural gradients in site productivity may be more fruitful in defining species response to light and N interactions. / Forestry, Faculty of / Graduate

Understanding soil fertility issues in the Middle Mountains of Nepal requires interdisciplinary research, integrating biophysical and socio-economic factors. Soil degradation is associated with a wide range of human activities, natural processes, and the wider economic, political and social aspects of their setting. This study focuses on a in the Middle Mountains and addresses four research questions: What is the current soil fertility status? How is it changing? Why is it changing? and What are the implications for production, sustainability and management? Soil surveys, plot studies, nutrient balance modelling, household questionnaires and GIS mapping techniques are used to address these questions. The overall soil fertility conditions of the study area are poor and appear to be declining under most land uses. Soil pH averages 4.8 ± 0.4 and is below desirable levels for crop production. Soil carbon (0.99 ± 0.5 %) and cation exchange capacity (10.8 ± 4.1 cmol kg⁻¹) are low, and available phosphorus (16.6 ± 18.9 mg kg⁻¹) is a concern given the low pH. Land use is the most important factor influencing soil fertility with khet (irrigated agriculture) showing the best fertility status (pH 5.2, Ca 5.3 cmol kg⁻¹ and available P 21.6 mg kg⁻¹), followed by bari, and grassland, with forest soil fertility being the poorest (pH 4.2, Ca 0.9 cmol kg⁻¹ and available P 0.7 mg kg⁻¹). Soil type is the second most important factor influencing soil fertility, with red soils displaying significantly lower available P than non-red soils (9.8 versus 22.1 mg kg⁻¹). Phosphorus sorption studies indicate the high P fixation capacity of red soils, 1.2 g kg⁻¹ compared to 0.3 g kg⁻¹ calculated for non-red soils. Extrapolation from site specific data to a spatial coverage using statistical analysis and GIS techniques indicates that only 14% of the classified areas have adequate pH, available P and exchangeable Ca, and 29% of the area has a high P fixation capacity (>1.5 g kg⁻¹). Nutrient balance modelling provides estimates of nutrient depletion from the soil pool and raises concerns about the sustainability of upland farming, intensive vegetable crop production and forest nutrient cycling. Dryland maize production results in deficits of 188 kg N, 38 kg P205 and 21 kg Ca per ha furrow slice Rice-wheat cultivation on irrigated land appears to have limited impact on the soil nutrient pool, but the addition of premonsoon maize to the rotation results in deficits of 106 kg N and 12 kg P₂O₅ per ha furrow slice. Rates of soil fertility depletion estimated from differences in soil fertility between land uses indicate substantial N and Ca losses from forest land (94 and 57 kg ha per furrow slice respectively). Land use change, the impact on nutrient flows and relationships between nutrient inputs, crop uptake, nutrient balances and soil fertility provide an understanding of why soil fertility is changing. Historical forest cover data indicates substantial deforestation during the 1950-1960 period, a subsequent reversal in the 1972-1990 period associated with afforestation efforts, and renewed losses in the 1990s. Forest soils receive minimal nutrient inputs and large biomass removal results in a low soil fertility status. Expansion and marginalization of dryland agriculture were noted from 1972-1990, as former grazing, shrub and abandoned lands were terraced and cultivated. Nutrient fluxes indicate that inputs are insufficient to maintain the soil nutrient pool under dryland cultivation due to the high nutrient requirements of maize and nutrient losses through erosion. Nutrient balances for maize and wheat are positively correlated with nutrient inputs but relationships with soil fertility are weak. On irrigated khet lands, cropping has intensified and cash crop production has prompted the use of agrochemicals. Excess fertilization is leading to eutrophication and the high use of agrochemicals is a health concern. Nutrient fluxes on khet fields appear to be sustainable due to the addition of nutrients through irrigation and sediment trapping, but may be insufficient to maintain triple cropping. Grass and shrub land dynamics are characterized by minimal inputs and low productivity. The traditional farming system appears to have been sustainable, but triple cropping and increased vegetable production are threatening sustainability. The transfer of nutrients within the fanriing system is unbalanced. Under intensive production, nutrients on khet land are being depleted, poor farmers are shifting their limited compost inputs from bari to khet fields, and biomass collected from forests, disrupts the natural nutrient cycle. Population growth, land tenure, culture and poverty are the underlying socio-economic factors which influence farming system dynamics, directly impact nutrient inputs, and indirectly drive soil fertility degradation. Population growth rates of 2.6% have contributed to agricultural intensification and marginalization, and pressure on forest resources. The distribution of land is highly skewed with 15% of the surveyed households owning 46% of the land. Women play a central role in soil fertility management through their responsibilities for livestock care, litter collection and compost application, but increasing workloads related to commercial milk production, cash cropping and the off-farm employment of males are a major concern. Agricultural assets, farm gross margins, market oriented production, commercial milk production and off-farm employment provide indicators of economic well-being and are positively correlated with nutrient inputs. Total returns and gross margins are greatest for households growing vegetable crops as part of their rotation, and these households apply significantly more compost and fertilizer to both khet and bari land. Access to land is a key factor driving nutrient management and influencing economic well-being. Land is the main agricultural asset in the study area, khet land is the most productive and khet provides the greatest opportunity of cash crop production. However, given the increased labour demands for triple cropping, vegetable production and commercial milk production, the social sustainability is being threatened. Some 47% of the households were not able to fulfil their basic need requirements from the land they farm. They will have no alternative but to exhaust the capital stock of soil nutrients rather than investing in soil fertility. Maintenance of soil fertility is essential to meet the basic food and resource needs of the growing population. Organic matter management is critical, supplying macro- and micro nutrients, reducing acidification, maintaining soil structure and enhancing microbial activity. Water management and sediment trapping on lowland fields provide additional nutrients on khet land; soil acidity on upland fields and forest land needs to be better managed given the increased fertilizer use on bari and high biomass removal from forests; and the incorporation of N fixing species into agricultural production systems are an option which may provide additional animal fodder and help sustain soil fertility. / Graduate and Postdoctoral Studies / Graduate

Biochar’s high porosity and negative surface charge allows for numerous soil and plant benefits such as increased water retention, high nutrient availability, and plant growth. By analysing biochar’s effect of all of these factors, a system can be put in place in which soils can be remediated with the proper soil amendments. This report discusses and tests the effects of varying rates of biochar on pH levels, cation exchange capacity, and nutrient exchangeability (of calcium, magnesium, sodium, and potassium) in soil. Corn plants were also grown in soils of varying amendment types and analysed for plant growth and germination to determine soil effects on the plant. Testing showed significant differences between treatment types in all areas tested except plant germination. A 2:1 ratio of biochar to compost produced the best overall results for the soil used in testing. This treatment maintained acceptable levels of exchangeable nutrients while raising pH and cation exchange capacity, and also raised the plant growth in the soil by 30%. However, for added soil health, gypsum or calcium fertilizer should be added to the soil to remediate low calcium exchangeability. This testing confirmed that biochar does have a strong positive influence on soil and plant health when used in combination with compost.

No description available.

Rye seedlings grown on differently fertilized plats at Chatham, Virginia, and at Fishersville, Virginia, for the year 1928, and tested by the Neubauer seedling method for phosphorus gave no clue to the amount and availability of the phosphatic fertilizer added. Therefore, the Neubauer seedling method as devised by Neubauer did not prove to be of value in determining the phosphorus availability of Virginia soils under the conditions prevailing in 1928. / M.S.

Experiments were conducted to monitor nutrient dynamics in the forest floor of an upland Appalachian oak forest stands following clearcutting and whole-tree removal. Samples from the L, F, H, and A₁ layers were collected during June, August, and November of 1979 and 1980. Monthly litterfall was collected from October, 1979, through October, 1980. Soil solution samples were extracted on a biweekly basis from April, 1980, through March, 1981, and concurrent soil moisture and temperature determinations were made. All samples were collected from the clearcut area and an adjacent uncut area. Nutrient analyses included total N, P, K, Ca, and Mg, and pH, NH₄-N, and NO₃-N for the soil solutions only. Comparisons were made between nutrient contents in the forest floor and mineral soil from the clearcut and uncut areas, between nutrient contents within forest floor layers within each area, and between nutrient contents collected over time within each area. Similar comparisons were made using litterfall nutrient contents and soil solution nutrient concentrations. Immediate clearcutting effects were most pronounced on the L layer of the forest floor, due to the logging slash input. Immediately after cutting the L layer in the cut area had a dry weight over 9,500 times that of the L layer in the uncut area. This logging slash rapidly became incorporated into the forest floor of the cut area, and after 15 months, the cut area had a forest floor slightly higher in dry weight and nutrient content than did the uncut area. Slash inputs accounted for these increases, since over the course of the study the cut area received only 14% of the litterfall that occurred in the uncut area. Soil temperature, moisture, and soil solution NH₄-N concentrations were all higher in the clearcut area. Soil solution NO₃-N concentrations were variable but generally the same in both areas. After 15 months following clearcutting and whole-tree removal, the forest floor in the clearcut area was slightly higher in dry weight and nutrient content than an adjacent uncut area, and no site degradation was noted. / Ph. D.

The foregoing paper reports a study on the effect of various organic compounds on the growth of Azotobacter. The study was induced by the theory that the soil contains organic substances which are deleterious to plant growth and which are important factors in influencing soil fertility. It is, therefore, interesting to determine if this toxicity extends to the lower plants. The Azotobacter was chosen as a representative of the soil flora since it is of recognized importance in the maintenance of the soil fertility and its growth may be accurately measured by analytical means. The compounds used were those likely to be constituents of the soil. The results of the study indicate that fixation of nitrogen by Azotobacter is only slightly influenced by most of the compounds investigated. A depression is noted in many cases but it is usually the result of a relatively high concentration of the compound used. Hydroquinone and Salicylic Aldehyde revealed the most toxic properties of any compounds studied. Esculin, Quinic Acid, and Borneal afforded marked stimulation to the growth of the organism. The effects of the compounds on Azotobacter are not, as a rule, in accord with what has been reported of their action on the higher plants. In concentrations which are fatal to certain higher plants, many of the compounds only slightly depressed fixation. A number of nitrogenous bodies were investigated. Such compounds as Nicotine, Picoline, and Skatol exhibited toxic properties commensurate to those usually ascribed to these substances. Caffeine appeared to stimulate the growth of the organism. Many of the nitrogenous compounds used which have been reported as beneficial to higher plants exercised a marked depression on fixation. It appears that the simpler compounds were more pronounced in this respect than were the more complex ones. It is suggested that this condition is not one of toxicity but that the nitrogen of the compounds was utilized by the Azotobacter in preference to that of the atmosphere. Urea, Glycocoll, Formamide, and Allantoin were especially active in depressing fixation. / Master of Science