Made available in DSpace on 2014-06-11T19:22:16Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-07-22Bitstream added on 2014-06-13T20:28:26Z : No. of bitstreams: 1 costa_chmc_me_botfca.pdf: 444896 bytes, checksum: 79a884c18686d0a77b3357b8cbc1bcfb (MD5) Bitstreams deleted on 2015-08-07T12:19:54Z: costa_chmc_me_botfca.pdf,. Added 1 bitstream(s) on 2015-08-07T12:20:56Z : No. of bitstreams: 1 000678831.pdf: 1444305 bytes, checksum: d3e614871d6cd55de66eda01f9f2bdd0 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / No sistema plantio direto praticamente não há revolvimento do solo e o consequente acúmulo de fertilizantes na superfície acelera o processo de acidificação, contínuo e acentuado que ocorre naturalmente em solos de regiões úmidas, onde, geralmente, é observada baixa disponibilidade de nutrientes e elevados teores de alumínio. Assim, da mesma forma que no sistema de cultivo convencional, no sistema plantio direto também existe a necessidade de aplicação de insumos em superfície, especialmente, materiais corretivos de acidez. Dentro deste enfoque, o trabalho foi desenvolvido na Fazenda Experimental Lageado, pertencente à Faculdade de Ciências Agronômicas – UNESP, Campus de Botucatu (SP), dando continuidade a um projeto de pesquisa que vem sendo conduzido desde 2002, com o objetivo de avaliar o efeito residual da aplicação superficial de corretivos na correção da acidez do solo, bem como na nutrição, na produtividade das culturas da soja e do sorgo e na produção de matéria seca e acúmulo de nutrientes da aveia-preta em região de inverno seco. O delineamento experimental utilizado foi em blocos casualizados em parcelas subdivididas, com 4 repetições. As parcelas foram constituídas por quatro doses de calcário (0, 1000, 2000 e 4000 kg ha-1) e as subparcelas por duas doses de gesso agrícola (0 e 2100 kg ha-1), aplicado em novembro 2004. Como cultura de verão foi utilizada a cultura da soja e na entressafra as culturas da aveia-preta e sorgo granífero. A aplicação de calcário em superfície promoveu diminuição da acidez e elevação nos teores de fósforo, cálcio, magnésio e matéria orgânica, em praticamente todo perfil do solo. A aplicação de gesso agrícola promoveu aumentos nos 2 teores de Ca trocável e S-SO42-, e diminuição no teor de Al trocável no solo... / In no tillage system the absence of soil mobilization consequently decreases places fertilizers on surface, affecting the acidification process. Like in conventional system, in no tillage it is also necessary input application, especially materials for acidity correction. The experiment was carried out in an experimental area, in the city of Botucatu (SP, Brazil), continuing a research project that has been conducted since 2002, to evaluate the long-term effects of surface application of lime and gypsum on acidity correction, nutrition, yield of soybean and sorghum, and dry matter production and nutrients accumulation on black oat in a dry winter region. The experimental design was the completely randomized with subdivided plots and four replications. The mains plots consisted of four dolomite limestone levels (0, 1000, 2000 e 4000 kg ha-1) and the subplots consisted areas with and without gypsum (0 and 2100 kg ha-1), applied in November 2004. Soybean was the summer crops and the off-season crops are black oat and grain sorghum Lime surface application reduced soil acidity and increased phosphorus, calcium, magnesium and organic matter, practically all the soil profile. Phosphogypsum application promoted increasing exchangeable Ca and S-SO42- contents, and decreased exchangeable Al in the soil, favoring the effects of surface liming on soil properties, mainly the surface layer (0-0.20 m). Base saturation values obtained at a depth of 0-0.20 m with liming were lower than those estimated by BS method, even with phosphogypsum application. Liming increased, on soybeans, foliar contents of N, P, Ca, Mg and S in 2008/09, and N, Ca and Mg, in 2009/10. In the presence of phosphogypsum increased the levels of N In no tillage system the absence of soil mobilization consequently... (Complete abstract click electronic access below)

The effects of surface applications of poultry manure on pH, exchangeable AI, exchangeable Al saturation and levels of available macronutrients in the surface and subsurface layers were investigated in some acid soils from the KwaZulu-Natal Midlands. Three field sites with a history of long-term applications of poultry manure were compared with adjacent fields where no manure had been applied. Results generally showed an increase in pHwater, pHKCI, exchangeable Ca, Mg, and K and extractable P and a decrease in exchangeable Al and exchangeable Al saturation in the surface soil to the depth to which the manure had been incorporated. Results also provided evidence for substantial downward movement of Ca and Mg into the subsoil layers (i.e. 30-60 cm) and their accumulation in exchangeable forms. There was a concomitant general increase in pHKcl and pHwater and decrease in exchangeable Al and exchangeable AI saturation in the subsoil layers. These results demonstrate that, under field conditions, surface applications of poultry manure can cause the amelioration of subsoil acidity. This is an extremely important finding since subsoil acidity is characteristically extremely difficult and costly to ameliorate. A leaching column study was subsequently conducted to investigate the mechanisms by which surface applications of poultry manure ameliorate both top- and subsoil acidity. The soil used, originating from one of the field sites, had not previously been treated with poultry manure and had a subsoil pHKCI of 4.25 and an exchangeable acidity concentration of 1.79 cmolJkg. Three forms of poultry manure (layer, broiler and free range) were incorporated into the surface 5 cm of soil columns at rates equivalent to 5, 10 and 30 Mg/ha. Columns were maintained in glasshouse conditions for a period of 108 days and over that period they were leached on four separate occasions (receiving a total of 825 mm of simulated rainfall). At the conclusion of the experiment, the soil columns were cut into sections for chemical analysis. Applications of poultry manure to the surface soil markedly increased pHwater, pHKcl, exchangeable Ca, Mg, K and Na concentrations and decreased exchangeable Al levels in the surface 5 cm layer. They also increased the concentrations of soluble C, soluble salts, total Al and organically-complexed Al in soil solution. These effects were most pronounced with layer manure and greater at the higher rate of application. The manure-induced decrease in exchangeable AI, but increase in total AI, in soil solution was attributed to soluble salts, originating from the manure, displacing exchangeable Al into solution where it was subsequently complexed by soluble organic matter. Analysis of subsoil layers (5-15, 15-25, 25-35 and 35-45 cm) at the conclusion of the experiment showed that surface applications of poultry manure decreased concentrations of exchangeable Al in the subsoil but had no effect on pHKCl and depressed values for pHwater. It was suggested that manure-derived urea leached into the subsoil and was then hydrolysed causing an increase in pH and precipitation of exchangeable Al as insoluble hydroxy-AI oxides. Towards the conclusion of the experiment nitrification began to proceed, causing subsoil pHKCl values to decrease back to their original values. Analysis of the inorganic-N content of leachates and soil layers provided circumstantial evidence for this mechanism. High concentrations of soluble salts in the subsoil layers (caused by leaching from the manure) resulted in displacement of exchangeable A13+ and W into soil solution so that the electrical conductivity and concentrations of total and monomeric Al were elevated and pHwater was depressed in the subsoil (15-45 cm) of poultry manure-treated columns. It was concluded that the results underline the opposing effects that poultry manure applications have on (i) raising soil pH and lowering exchangeable Al but at the same time (ii) greatly increasing soluble salt concentrations and thus displacing At3+ and H+ back into soil solution. They also have suggested the importance of the release of N during manure decomposition in influencing soil pH (through the processes of ammonification, urea hydrolysis and nitrification) and therefore other soil chemical properties. It is, however, clear that the long-term effect of surface applications of poultry manure is generally to ameliorate subsoil acidity by raising subsoil pH and lowering exchangeable Al concentrations. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2001.

Magistro darbe tiriamas skirtingų kalkinių medžiagų poveikis dirvožemio potencialiajam rūgštingumui ir judriajam aliuminiui. Darbo objektas – keturios kalkinės medžiagos: malta kreida, „Agrokalkės” (klinčių ir nedegtų kalkių miltelių mišinys), dolomitmičiai (dolomito atsijos), ir granuliuota kalkinė medžiaga „Kalktrąšė”. Darbo metodai – kalkinėmis medžiagomis buvo pakalkintos dvi, pasotinto balkšvažemio Dystric Albeluvisol ir nepasotinto balkšvažemio Eutric Albeluvisol, lauko bandymų aikštelės; dirvožemio potencialusis rūgštingumas nustatytas laboratorijoje elektroniniu pH-metru, judriojo aliuminio kiekis Sokolovo metodu; gauti duomenys palyginti tarpusavyje matematiniais-statistiniais metodais. Darbo rezultatai. Atlikus tyrimus nustatyta, kad efektyviausiai, bei statistiškai patikimai (p<0,05) dirvožemio rūgštingumą sumažino dulkios kalkinės medžiagos – kreida ir „Agrokalkės”. Stambesnės frakcijos, trupintos kalkinės medžiagos – dolomitmičių statistiškai patikimas poveikis nustatytas tik antrojoje bandymų aikštelėje nepasotintame balkšvažemyje Eutric Albeluvisol praėjus aštuoniolikai mėnesių po kalkinimo. Granuliuota kalkinė medžiaga „Kalktrąšė“ statistiškai nepatikimai veikė dirvožemio rūgštingumą. Efektyviausiai (99%) statistiškai patikimai (p<0,05), judriojo Al kiekį sumažino „Agrokalkės“. Taip pat efektyviai, kreida 97% ir dolomitmilčiai 79%, statistiškai patikimai (p<0,05) sumažino judriojo Al kiekį dirvožemyje. „Kalktrąšė“ iš visų tirtų kalkinių medžiagų prasčiausiai... [toliau žr. visą tekstą] / The Master Thesis analyses the impact of different liming materials on potential soil acidity and mobile aluminium. Object – four liming materials: powder chalk, agrolime (mixture of limestone and uncalcined lime powder), dolomite powder (dolomite siftings), and pelletized lime fertilizer “Kalktrąšė”. Methods – two experimental field plots, Dystric Albeluvisol and Eutric Albeluvisol, had been limed using four different liming materials; potential soil acidity had been determined in the laboratory by the electronic pH-metre, the amount of mobile aluminium was estimated by Sokolov method; the obtained data were inter-compared by the mathematical-statistical methods. Results. The research demonstrated that the use of powdered lime materials, i.e. chalk and agrolime, resulted in the most effective and statistically reliable (p<0.05) reduction of soil acidity. A statistically reliable impact of dolomite powder, a crushed lime material of larger fractions, was recorded only in the second testing ground, Eutric Albeluvisol, eighteen months after liming. Moreover, the effect of pelletized lime fertilizer “Kalktrąšė” on soil acidity was not statistically reliable. In contrast, agrolime was the most effective (99%) and statistically reliable (p<0.05) in reducing the amount of mobile aluminium. A similar, statistically reliable (p<0.05) impact was caused by chalk 97% and dolomite 79% powder (p<0.05), what reduce mobile Al in soil. Among all liming materials “Kalktrąšė” resulted in the... [to full text]

Thesis (M.Sc.) - University of KwaZulu-Natal, Pietermaritzburg, 2008. / Full text also available online. Scroll down for electronic link.

Thesis--Stockholms Högskola, 1922. / Chapter 7-8 in German. "Särtryck ur Meddelanden från Statens Skogsförsöksanstalt, häft. 19, 1922." Includes bibliographical references (p. 201-208).

Ph. D.

Soil acidity is a major cause of low yields of alfalfa (Medicago sativa L.) in the southeastern United States. Two field experiments were conducted on an Ernest silt loam soil (fine—loamy, mixed, mesic Aquic Fragiudult) to determine what conditions are necessary for optimal alfalfa growth in an acid soil environment. In the first experiment alfalfa was no—till planted to evaluate the influence of surface applied dolomitic limestone at 0 and 6.7 Mg/ha either 8 or 20 months before planting and at planting on alfalfa performance under acidic conditions. Yield increases, greater than two fold, resulted from surface application of limestone regardless of time of application. In the second field experiment treatments included surface and incorporated dolomitic limestone at either 6.5 or 13.0 Mg/ha, gypsum at 13.0 Mg/ha, foliar Mo at 560 g/ha and N as a split. Yields increased in response to surface and incorporated lime, Ca, Mo and N application, possibly as a result of Al activities in soil solution being as low as 0 and 0.05 uM in the surface and 1 m depth samples, respectively, for the surface limed soils. Low activity of Al in soil solution may explain why subsurface acidity was not toxic to alfalfa grown on these soils. This study showed that surface limestone at half the recommended rate is adequate for the growth of alfalfa under acidic conditions. The implanted soil mass technique was used to evaluate the influence of subsurface amendments (Ca, N, Ca and N, KOH and Ca(OH)2) on alfalfa root growth and N fixation on soils that received either 0 or 6.7 Mg/ha surface applied limestone. Of the various subsurface amendments the Ca(OH)2 treatment produced the most root growth and N fixation. This study showed that both the reduction in acidity and the availability of Ca are necessary for optimal N fixation and root growth. In vitro studies conducted in growth pouches showed that pH 4.5 nutrient solution was not ·detrimental to alfalfa growth unless A1 was present. Addition of 3.0 mM Ca to a nutrient solution containing 0.08 mM Al alleviated toxic effects of Al on alfalfa growth. No-till alfalfa can thus be grown on acid soils with surface lime by providing Ca and reducing acidity. / Ph. D. / incomplete_metadata

The biodegradation potential of two subsurface soils was characterized by monitoring the biodegradation of short-chain fatty acids in anaerobic soil microcosms. Valerate, butyrate, propionate, and acetate concentrations were monitored independently using separate microcosms. The effect of sulfate on the microbial communities was also investigated. One soil, from Newport News, Virginia, consisted of a sandy loam collected beneath a low lying, grassy field. The microcosms containing the soil were characterized by: a neutral pH, the utilization of sulfate with concomitant precipitation of iron sulfide , an increase in the degradation rate as a result of sulfate addition, and a production of bicarbonate directly related to acid mineralization. Another soil, from Blacksburg, Virginia, consisted of a silty-clay collected beneath a wooded hilltop. Microcosms containing the soil were characterized by : a pH between 4 and 5, little sulfate utilization with no visible iron sulfide precipitation, an increase in degradation rates upon the addition of sulfate, and little or no accumulation of bicarbonate. These results indicate that short-chain fatty acids are readily degraded in subsurface anaerobic soil systems and that these rates are dependent on the availability of electron acceptors and the diversity of the indigenous population. / Master of Science

Thesis (MSc. Agriculture(Soil Science) -- University of Limpopo, 2018 / Soil acidity is one of the abiotic stress factors that greatly limit the productivity of crops on farmers’ fields. A greenhouse study was carried out over two summer growing seasons to evaluate the effect of lime and phosphorus (P) application rates on the growth, yield and root attributes of a determinate cowpea variety on acid soil. The experiment was laid out as a 4x5 factorial arrangement with 4 replications. Treatment factors comprised of variable rates of Vaalburg dolomitic lime (0, 2, 4 and 6 t ha-1) and P (0, 15, 30, 45 and 60 kg ha-1) using single super phosphate, 10.5% P. The two treatment factors were combined resulting in a total of 20 treatment combinations. Data collected included cowpea growth parameters, crop phenology, yield attributes and root characteristics. While cowpea plants with no P application consistently gave the least plant height, stem diameter, number and length of trifoliate leaves, the 6 t ha1 lime rate appears to be completely disadvantaged for all measured parameters with generally lower values than in soil filled pots without lime application. Results showed that soil pH was increased with 6 t ha-1 lime application while soil electrical conductivity (EC), percent of organic matter (OM) and total organic carbon (TOC) were all increased with increasing P and lime rates. All measured cowpea growth attributes such as plant height, stem diameter, number of trifoliate leaves, and leaf area were significantly increased (p≤0.05) with increasing P and lime rates. During the two planting seasons, P and lime application resulted in reduced (p≤0.05) duration to flowering, pod formation and physiological maturity. The 6 t ha-1 lime application produced higher number of pods (2.50) compared to the other rates. Application rates of 45 kg P ha-1 and 6 t ha-1 of lime produced superior number of seeds per pod with high values of (13.71) and (12.85), respectively. However, cowpea root attributes namely number of nodules per plant, the third branching root diameter, angle of adventitious root, tap root diameter at 5 and 10 cm, shallow and deep score were significantly increased at moderate P rate of 30 kg P ha-1. Overall, findings of this study revealed that application of both P fertiliser and lime were able to ameliorate the negative effect of P deficiency from soil acidity on the evaluated cowpea variety and promoted increased yield. Keywords: Acid soil, grain cowpea, P fertiliser, lime, growth, root characteristics, yield / National Research Foundation (NRF) and Department of Agriculture, Forestry and Fisheries (DAFF)

Thesis (M.Eng.)--University of Wollongong, 2006. / Typescript. Includes bibliographical references: leaf 174-183.