• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 5
  • 4
  • 4
  • 1
  • Tagged with
  • 18
  • 18
  • 18
  • 5
  • 5
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Properties of an Orthic Black Chernozem after 5 years of liquid and solid pig manure applications to annual and perennial crops

Adesanya, Theresa 09 January 2016 (has links)
Soil physical and chemical properties determine a soil's crop production potential and the sustainability of a production system. The objective of this study was to determine the effect of solid and liquid pig manure application on the physical and chemical properties of soil after 5 years of manure application. Solid pig manure increased saturated hydraulic conductivity (Ksat) by 110%, aggregate stability by 30%, available and total phosphorus by 471% and 52% respectively, available nitrogen by 38%, organic carbon by 29% and exchangeable K by 308%, and reduced soil bulk density by 14%. Liquid pig manure (LPM) also increased aggregate stability by 21%, exchangeable K by 45%, available P and total P by 258% and 27%, respectively and, reduced bulk density by 6%. An important finding was the 33% decrease in the concentration of exchangeable Ca in LPM-amended soils. Significant manure by cropping system interaction was also obtained for water retention parameters and available water, total nitrogen and electrical conductivity. There was no effect of pig manure on pH and exchangeable Mg concentrations. Soils under perennial vegetation had 31% greater Ksat, 26% increase in available N, 31% greater available P, 15% greater total P and 12% lower bulk density compared with those under annual crops. Our results show that SPM has a potential as a better organic amendment in improving physical and chemical properties of surface soils. / February 2016
2

Effects of municipal wastewater on soil chemical properties in cultivating turfgrass using subsurface drip irrigation

Tabatabaei, Sayyed-Hassan, Mousavi, Seyyed Mohammad, Mirlatifi, Seyed Majid, Sharifnia, Rezvan Sadat, Pessarakli, Mohammad 04 January 2017 (has links)
Knowing the concentrations of the nutrient elements in soils is important due to their toxic effect on humans and the environment. The aims of this study were to assess the effects of water quality, depths and distances of lateral installation on soil chemical properties during turfgrass cultivation. A field experiment was conducted using a Split Split Plot design based on the Randomized complete Block (RCB) with two treatments (well’s and wastewater), and eight sub-treatments (45 and 60 cm distance of the laterals and 15, 20, 25, and 30 cm depths of laterals) in three replicates on a sandy-loam soil, in Shahrekord, Iran. Soil samples were collected from 0-30 and 30-60 cm depth for measuring nitrate (NO3-), electrical conductivity (EC), and pH at the end of the experiment. During the experiment, fecal coliform (FC) were also measured at the soil surface. Results indicated that by increasing lateral distance, NO3- level increased in both layers. With installing laterals in deeper levels, NO3- concentration decreased at the beginning, then increased in the first layer, whereas in the second layer NO3- concentration decreased. In addition, installing laterals in deeper depth, caused an increase in soil EC in the top layer, but a decrease in the lower layer. However, the results showed that there was no significant effect of experimental factors on soil pH. The results also show that with increasing laterals depth, Fc level decreased at the soil surface.
3

Soil conditions and early crop growth after repeated manure applications

Japp, Mitchell Thomas 31 July 2007
Development of the swine and cattle industries has led to an increase of manure application to agricultural lands in Saskatchewan. Studies have been conducted to determine the nutrient benefits of swine manure application. However, a need was also identified for information on the effects of manure application on soil physical and chemical properties. The objective of this study was to examine the effect of repeated applications of manure on soil physical and chemical properties and to relate those effects to early plant growth and development.<p>Four experimental sites were used, representing the Dark Brown (Plenty), Brown (Riverhurst irrigated), Black (Dixon) and Gray (Melfort) Soil Zones of Saskatchewan, where liquid swine manure had been applied for four to seven years. At each site, treatments were 1) a control treatment, 2) a nitrogen based agronomic rate of manure application, 3) a high rate of manure application (2-4x the agronomic rate) and 4) a urea fertilizer treatment. At the Dixon site, the same two manure treatments with cattle manure were also examined.<p>Soil strength, as determined by penetration resistance measurements and barley (<i>Hordeum vulgare</i>) emergence were measured at two experimental sites (swine and cattle manure trials at Dixon, SK) in a field study. Penetration resistance was measured at 5, 10, 15 and 20 cm depths, 20, 39 and 123 days after seeding using a recording cone penetrograph. Twenty days after seeding, there were no significant differences among treatments at the 10, 15 and 20 cm depths. But, at the 5 cm depth, the control treatment had soil strength 0.11 MPa lower than the two manure rates. The manure treatments were not significantly different from the urea treatment. Thirty-nine days after seeding, the soil strength of the low rate manure treatment was 1.1 MPa greater than the control at the 10 cm depth, but not significantly different from the urea treatment. One hundred and twenty three days after seeding, the control treatment had greater soil strength than the high rate of manure at 5 and 10 cm depths by 0.28 and 0.71 MPa respectively. At the 20 cm depth, the high rate of manure had the greatest soil strength. Barley emergence on the two manured treatments did not differ significantly from the control. Aggregate size was measured in field samples collected from all sites. Aggregate size for the manured treatments did not differ from the control at any site.<p>Soil crust strength, flax emergence, infiltration rate, salinity, sodicity, coefficient of linear extensibility (COLE) and modulus of rupture were measured under controlled conditions in intact cores of soil removed from all five experimental sites. All soils were treated with a simulated rainfall from a Guelph Rainfall Simulator II. Following the simulated rainfall, crust strength was measured with a hand-held penetrometer. Soil crust strength was measured daily for 10 days as the cores dried. Repeated applications of liquid swine manure at either low or high rates decreased soil strength in the Plenty, Riverhurst and Melfort soils, and increased soil strength in the Dixon soil. Repeated applications of liquid swine manure at low rates caused flax emergence to decrease for the Riverhurst soil compared to its control and had no significant effect at the other sites. There were no notable differences in infiltration rates among treatments. Repeated applications of liquid swine manure caused salinity (EC) to increase slightly for the Plenty and Riverhurst soils, and sodicity (ESP) to increase slightly for the Melfort and Dixon soils relative to their control. The COLE and modulus of rupture measurements indicated no significant effects and were inconclusive due to difficulties in measurement. <p>None of the properties measured in any of the treatments exceeded threshold values for soil productivity, or where plant injury might be considered an issue. It is concluded that repeated (four to seven) annual applications of liquid swine or cattle manure would not cause any large alterations in soil strength, aggregation, infiltration, salinity, or sodicity that would affect early plant growth and development. This was supported by field and lab measurements of emergence that showed limited effect.
4

Soil conditions and early crop growth after repeated manure applications

Japp, Mitchell Thomas 31 July 2007 (has links)
Development of the swine and cattle industries has led to an increase of manure application to agricultural lands in Saskatchewan. Studies have been conducted to determine the nutrient benefits of swine manure application. However, a need was also identified for information on the effects of manure application on soil physical and chemical properties. The objective of this study was to examine the effect of repeated applications of manure on soil physical and chemical properties and to relate those effects to early plant growth and development.<p>Four experimental sites were used, representing the Dark Brown (Plenty), Brown (Riverhurst irrigated), Black (Dixon) and Gray (Melfort) Soil Zones of Saskatchewan, where liquid swine manure had been applied for four to seven years. At each site, treatments were 1) a control treatment, 2) a nitrogen based agronomic rate of manure application, 3) a high rate of manure application (2-4x the agronomic rate) and 4) a urea fertilizer treatment. At the Dixon site, the same two manure treatments with cattle manure were also examined.<p>Soil strength, as determined by penetration resistance measurements and barley (<i>Hordeum vulgare</i>) emergence were measured at two experimental sites (swine and cattle manure trials at Dixon, SK) in a field study. Penetration resistance was measured at 5, 10, 15 and 20 cm depths, 20, 39 and 123 days after seeding using a recording cone penetrograph. Twenty days after seeding, there were no significant differences among treatments at the 10, 15 and 20 cm depths. But, at the 5 cm depth, the control treatment had soil strength 0.11 MPa lower than the two manure rates. The manure treatments were not significantly different from the urea treatment. Thirty-nine days after seeding, the soil strength of the low rate manure treatment was 1.1 MPa greater than the control at the 10 cm depth, but not significantly different from the urea treatment. One hundred and twenty three days after seeding, the control treatment had greater soil strength than the high rate of manure at 5 and 10 cm depths by 0.28 and 0.71 MPa respectively. At the 20 cm depth, the high rate of manure had the greatest soil strength. Barley emergence on the two manured treatments did not differ significantly from the control. Aggregate size was measured in field samples collected from all sites. Aggregate size for the manured treatments did not differ from the control at any site.<p>Soil crust strength, flax emergence, infiltration rate, salinity, sodicity, coefficient of linear extensibility (COLE) and modulus of rupture were measured under controlled conditions in intact cores of soil removed from all five experimental sites. All soils were treated with a simulated rainfall from a Guelph Rainfall Simulator II. Following the simulated rainfall, crust strength was measured with a hand-held penetrometer. Soil crust strength was measured daily for 10 days as the cores dried. Repeated applications of liquid swine manure at either low or high rates decreased soil strength in the Plenty, Riverhurst and Melfort soils, and increased soil strength in the Dixon soil. Repeated applications of liquid swine manure at low rates caused flax emergence to decrease for the Riverhurst soil compared to its control and had no significant effect at the other sites. There were no notable differences in infiltration rates among treatments. Repeated applications of liquid swine manure caused salinity (EC) to increase slightly for the Plenty and Riverhurst soils, and sodicity (ESP) to increase slightly for the Melfort and Dixon soils relative to their control. The COLE and modulus of rupture measurements indicated no significant effects and were inconclusive due to difficulties in measurement. <p>None of the properties measured in any of the treatments exceeded threshold values for soil productivity, or where plant injury might be considered an issue. It is concluded that repeated (four to seven) annual applications of liquid swine or cattle manure would not cause any large alterations in soil strength, aggregation, infiltration, salinity, or sodicity that would affect early plant growth and development. This was supported by field and lab measurements of emergence that showed limited effect.
5

Estudo do uso de lodo de estações de tratamento de água e de esgoto urbano nas propriedades químicas do solo

Laperuta Neto, Jayme [UNESP] 25 August 2006 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:26:46Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-08-25Bitstream added on 2014-06-13T19:34:36Z : No. of bitstreams: 1 laperutaneto_j_me_botfca.pdf: 1510258 bytes, checksum: f88f2af3fb61d4a1517b0357317acec0 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Universidade Estadual Paulista (UNESP) / No ano de 2005 foi realizado, em área da Estação de tratamento de Esgoto da Fazenda Experimental Lageado, campus da Universidade Estadual Paulista - Botucatu, SP, experimento com lodos de esgoto, proveniente da própria estação do Lageado, da estação de tratamento de esgoto da SABESP, no município de Franca-SP, e com lodo do tratamento de água, proveniente da Estação de Tratamento de Água da SABESP no município de Botucatu-SP, tendo por objetivo, a avaliação dos efeitos causados pela aplicação desses resíduos em Neosolo Quartzarênico e Latossolo Vermelho Distroférrico , irrigados com água tratada fornecida pela SABESP e por água residuária da própria estação de tratamento do Lageado. As variáveis analisadas foram : pH, acidez potencial, matéria orgânica, capacidade de troca de cátions (CTC), soma de bases (SB), saturação em bases (V%), P(resina), Al3+, K, Ca, Mg, S, B, Cu, Fe, Mn e Zn. O experimento foi constituído de tratamentos, os quais foram montados ao acaso, em esquema fatorial 3x2x3x2, sendo 3 épocas, dois tipos de solo, 3 tipos de lodo, 2 tipos de água, com 3 repetições por tratamento, resultando no total 108 amostras. Os tratamentos foram preparados em recipientes de 9,50 litros, contendo uma mistura de 70% do volume de solo e os 30 % restantes de lodo. 2 O lodo da ETE-Lageado apresentou para a maioria dos elementos estudados, teores médios maiores, que os do lodo da ETE-Franca e ETA-Botucatu que foram semelhantes. Os teores da maioria dos elementos variam com a época, para os três lodos, sendo seus comportamentos explicados por modelos polinomiais de segunda ordem na quase totalidade. Os lodos podem ser aplicados ao solo, uma vez que os níveis dos nutrientes, foram considerados de médio para alto de acordo com Raij et al. (1996), e os níveis de Cu e Zn não se apresentaram tóxicos (U.S.EPA,1996). / An experiment using sludge from Lageado sewage farm, from SABESP sewage farm in the city of Franca-SP and sludge from SABESP waterworks in the city of Botucatu-SP was carried out in Lageado Experimental Farm, campus of Universidade Estadual Paulista, Botucatu-SP in the year of 2005, with the purpose of assessing the effects caused by the application of these residues to quartzose sand and oxisol irrigated with purified water supplied by SABESP and residuary water from Lageado waterworks. The analysed variables were: pH, potencial acidity, organic matter, cation exchange capacity (CEC), base addition (BA), base saturation (V%), P(resin), Al+3, K, Ca, Mg, S, B, Cu, Fe, Mn and Zn. The experiment consisted of treatments, which were assembled at random, in a 3x2x3x2 factorial scheme, being respectively: 3 time, 2 types of soil, 3 4 types of sludge, 2 types of water, with three repetitions for each treatment, resulting in a total of 108 samples. The treatments were prepared in 9,5 liter containers with a mixture of 70% of the soil volume and 30 % of sludge. The sludge from the Lageado sewage farm presented, for most of the analysed elements, higher average contents than the ones from Franca sewage farm and Botucatu waterworks that were both similar. The amount of most elements varies according to time for all of 3 types of sludge, their behavior being explained through second order polynomial models almost in its totality. The sludges may be used as a soil conditioner, since the levels of the nutrients were considered as average to high according to Raij et al. (1996) and Cu an Zn levels havenþt showed as being toxic (USEPA, 1996). 1 1 kKey words: sludge; soil - chemical properties, wasted waters, sanitation.
6

Greenhouse evaluation of maize performance and changes in chemical properties of soil following application of winery solid waste composts

Masowa, Manare Maxson January 2015 (has links)
Thesis (M.Sc.(Soil Science)) -- University of Limpopo, 2015 / Winery solid waste materials namely, wine filter materials (FM), grape marc (berry stalks, skins and seeds) and chopped grapevine pruning canes were composted in heaps through a thermophilic process. The filter materials were mixed with the grape marc and grapevine prunings at five rates (10%, 25%, 50%, 75% and 100%) to produce five composts herein designated as C10FM, C25FM, C50FM, C75FM and C100FM, respectively. A laboratory incubation study was thereafter carried out to determine the nutrient release potential of the composts using two soil types with varying textural characteristics. Each compost was mixed with soil at a rate equivalent to 200 kg N ha-1 and the mineral N, available P and exchangeable K content determined over 42 days incubation period. Results revealed that the composts possess high C content and low C:N ratios; and released significantly higher NH4-N and K concentration relative to un-amended control. The differences in the amount of P mineralised among the five compost treatments were not significant while significantly higher amount of K was mineralised at higher FM mix rates. The composts were applied to maize cv. SNK2147 on sandy soil in a greenhouse pot study at five rates (5, 10, 20, 40 and 80 t ha-1) to determine their effects on crop growth and yield as well as on selected soil chemical properties. An un-fertilised control and NPK fertiliser treatments were included for comparison. The pots were arranged in a completely randomized design, with each treatment replicated four times. The C50FM, C75FM and C100FM treatments applied at 80 t ha-1 gave significantly higher maize dry matter yield than the NPK fertiliser treatment. Quantitative estimates of the optimum compost rate for dry matter production ranged from 450 to 1842 g pot-1. Application of these composts significantly increased dry matter yield, plant height, stem diameter and the number of functional leaves per plant compared to the un-fertilised control. The K content of shoot from composts treatments exceeded the critical nutritional level of 3.3%. Plant tissue Zn content from C10FM, C25FM and C50FM treatments exceeded the critical nutritional level of 15 mg kg-1 while the residual soil K, Na and Zn contents after crop harvest were significantly increased following compost application. Similarly, the residual P was significantly increased in C25FM, C75FM and C100FM treatments after harvest. In conclusion, application of these composts exerted beneficial effects on maize performance and soil. Field studies under variable conditions are recommended to validate these findings. Keywords: wine, compost, nutrient release potential, maize, soil chemical properties
7

Estudo do uso de lodo de estações de tratamento de água e de esgoto urbano nas propriedades químicas do solo /

Laperuta Neto, Jayme, 1979- January 2006 (has links)
Orientador: Raimundo Leite Cruz / Banca: Roberto Lyra Villas Bôas / Banca: Tarlei Arriel Botrel / Resumo: No ano de 2005 foi realizado, em área da Estação de tratamento de Esgoto da Fazenda Experimental Lageado, campus da Universidade Estadual Paulista - Botucatu, SP, experimento com lodos de esgoto, proveniente da própria estação do Lageado, da estação de tratamento de esgoto da SABESP, no município de Franca-SP, e com lodo do tratamento de água, proveniente da Estação de Tratamento de Água da SABESP no município de Botucatu-SP, tendo por objetivo, a avaliação dos efeitos causados pela aplicação desses resíduos em Neosolo Quartzarênico e Latossolo Vermelho Distroférrico , irrigados com água tratada fornecida pela SABESP e por água residuária da própria estação de tratamento do Lageado. As variáveis analisadas foram : pH, acidez potencial, matéria orgânica, capacidade de troca de cátions (CTC), soma de bases (SB), saturação em bases (V%), P(resina), Al3+, K, Ca, Mg, S, B, Cu, Fe, Mn e Zn. O experimento foi constituído de tratamentos, os quais foram montados ao acaso, em esquema fatorial 3x2x3x2, sendo 3 épocas, dois tipos de solo, 3 tipos de lodo, 2 tipos de água, com 3 repetições por tratamento, resultando no total 108 amostras. Os tratamentos foram preparados em recipientes de 9,50 litros, contendo uma mistura de 70% do volume de solo e os 30 % restantes de lodo. 2 O lodo da ETE-Lageado apresentou para a maioria dos elementos estudados, teores médios maiores, que os do lodo da ETE-Franca e ETA-Botucatu que foram semelhantes. Os teores da maioria dos elementos variam com a época, para os três lodos, sendo seus comportamentos explicados por modelos polinomiais de segunda ordem na quase totalidade. Os lodos podem ser aplicados ao solo, uma vez que os níveis dos nutrientes, foram considerados de médio para alto de acordo com Raij et al. (1996), e os níveis de Cu e Zn não se apresentaram tóxicos (U.S.EPA,1996). / Abstract: An experiment using sludge from Lageado sewage farm, from SABESP sewage farm in the city of Franca-SP and sludge from SABESP waterworks in the city of Botucatu-SP was carried out in Lageado Experimental Farm, campus of Universidade Estadual Paulista, Botucatu-SP in the year of 2005, with the purpose of assessing the effects caused by the application of these residues to quartzose sand and oxisol irrigated with purified water supplied by SABESP and residuary water from Lageado waterworks. The analysed variables were: pH, potencial acidity, organic matter, cation exchange capacity (CEC), base addition (BA), base saturation (V%), P(resin), Al+3, K, Ca, Mg, S, B, Cu, Fe, Mn and Zn. The experiment consisted of treatments, which were assembled at random, in a 3x2x3x2 factorial scheme, being respectively: 3 time, 2 types of soil, 3 4 types of sludge, 2 types of water, with three repetitions for each treatment, resulting in a total of 108 samples. The treatments were prepared in 9,5 liter containers with a mixture of 70% of the soil volume and 30 % of sludge. The sludge from the Lageado sewage farm presented, for most of the analysed elements, higher average contents than the ones from Franca sewage farm and Botucatu waterworks that were both similar. The amount of most elements varies according to time for all of 3 types of sludge, their behavior being explained through second order polynomial models almost in its totality. The sludges may be used as a soil conditioner, since the levels of the nutrients were considered as average to high according to Raij et al. (1996) and Cu an Zn levels havenþt showed as being toxic (USEPA, 1996). 1 1 kKey words: sludge; soil - chemical properties, wasted waters, sanitation. / Mestre
8

Direct and residual effects of organic and inorganic fertilizers on soil chemical properties, microbial components and maize yield under long-term crop rotation

Asfaw Belay, Tedla 11 March 2002 (has links)
Management-induced degradation of soil chemical and microbial quality is one of the most pressing concerns and a considerable threat to the sustainability of agroecosystems. However, information on this important issue is limited and largely based on short-term studies. A long-term experiment initiated in 1939 at the University of Pretoria provided a unique opportunity to assess the direct and residual effects of manure and inorganic fertilizers on soil chemical properties, microbial components and maize yield in rotation with field pea. Long-term addition of manure resulted in increased total organic C (TOC), total N and available P levels in the soil. Seasonally, these nutrients exhibited variations that appeared to be related to influences of crop rotation. Soil N content in an adjacent native site remained relatively constant but tended to increase in the control and manured plots. Soil microbial biomass C, N and P and microbial populations were affected by previous manure application as well as by crop rotation. Microbial biomass and numbers were generally higher in the manured plots. Manure application also had substantial residual effects and resulted in maize grain yields higher than in the control. Long-term NPK application resulted in decreased TOC and basic cation contents, and lowering of soil pH. The decrease in TOC was greater in single fertilizer treatments whereas basic cation contents and pH declined more in the balanced fertilizer treatments. Soil microbial biomass and numbers were influenced by, and exhibited qualitative changes in response to, long-term fertilization. Crop rotation also exerted effects on chemical and microbial properties of the soil. Maize grain yield showed significant increases in response to balanced fertilizer treatments. Response of maize to simple fertilizer applications was not beneficial in terms of yield returns. These results suggest that judicious use of inorganic fertilizers may, in the long-term, maintain soil quality and productive capacity. A comparison of the effects of residual manure and NPK fertilizers on the content of selected nutrients, microbial properties, C and N inputs, tissue nutrient concentration and crop yield showed differences due to treatments. TOC, total N and available P levels were increased due to residual manure alone or in combination with NPK fertilizers. C and N inputs and tissue P concentration were also generally higher in manured than in the NPK treatment. However, the higher increase in nutrient contents of manured plots was not reflected in microbial properties of the soil. Despite lower nutrient levels, the NPK treatment resulted in relatively greater increases in microbial properties of the soil. The differential responses were largely due to differences in quality and decomposability of organic material. Organic material in the NPK treatment appeared to have a higher decomposition and turnover rate than in other treatments, suggesting that C limitation in soils of low C but good nutrient supply may be compensated by high turnover rates of the available organic materials. The beneficial effect of residual manure on microbial properties and crop yield was decreased by application of supplemental N fertilizer but remained unaffected by application of supplemental K fertilizer. The depressive effect of excess soil P levels on soil microbial properties and crop yield was exacerbated by supplemental N fertilizer and mitigated by supplemental manure and K fertilizer applied to residual P. The decrease in available P levels due to supplemental K application implies that this may serve as a viable alternative to ameliorate soils with excess P levels. / Thesis (PhD (Plant Production and Soil Science))--University of Pretoria, 2003. / Plant Production and Soil Science / unrestricted
9

Direct and residual effects of organic and inoganic fertilizers on soil chemical properties, microbial components and maize yield under long-term crop rotation

Tedla, Asfaw Belay 05 July 2010 (has links)
Management-induced degradation of soil chemical and microbial quality is one of the most pressing concerns and a considerable threat to the sustainability of agroecosystems. However, information on this important issue is limited and largely based on short-term studies. A long-term experiment initiated in 1939 at the University of Pretoria provided a unique opportunity to assess the direct and residual effects of manure and inorganic fertilizers on soil chemical properties, microbial components and maize yield in rotation with field pea. Long-term addition of manure resulted in increased total organic C (TO C), total Nand available P levels in the soil. Seasonally, these nutrients exhibited variations that appeared to be related to influences of crop rotation. Soil N content in an adjacent native site remained relatively constant but tended to increase in the control and manured plots. Soil microbial biomass C, Nand P and microbial populations were affected by previous manure application as well as by crop rotation. Microbial biomass and numbers were generally higher in the manured plots. Manure application also had substantial residual effects and resulted in maize grain yields higher than in the control. Long-term NPK application resulted in decreased TOC and basic cation contents, and lowering of soil pH. The decrease in TOC was greater in single fertilizer treatments whereas basic cation contents and pH declined more in the balanced fertilizer treatments. Soil microbial biomass and numbers were influenced by, and exhibited qualitative changes in response to, long-term fertilization. Crop rotation also exerted effects on chemical and microbial properties of the soil. Maize grain yield showed significant increases in response to balanced fertilizer treatments. Response of maize to simple fertilizer applications was not beneficial in terms of yield returns. These results suggest that judicious use of inorganic fertilizers may, in the long-term, maintain soil quality and productive capacity. A comparison of the effects of residual manure and NPK fertilizers on the content of selected nutrients, microbial properties, C and N inputs, tissue nutrient concentration and crop yield showed differences due to treatments. TOC, total N and available P levels were increased due to residual manure alone or in combination with NPK fertilizers. C and N inputs and tissue P concentration were also generally higher in manured than in the NPK treatment. However, the higher increase in nutrient contents of manured plots was not reflected in microbial properties of the soil. Despite lower nutrient levels, the NPK treatment resulted in relatively greater increases in microbial properties of the soil. The differential responses were largely due to differences in quality and decomposability of organic material. Organic material in the NPK treatment appeared to have a higher decomposition and turnover rate than in other treatments, suggesting that C limitation in soils of low C but good nutrient supply may be compensated by high turnover rates of the available organic materials. The beneficial effect of residual manure on microbial properties and crop yield was decreased by application of supplemental N fertilizer but remained unaffected by application of supplemental K fertilizer. The depressive effect of excess soil P levels on soil microbial properties and crop yield was exacerbated by supplemental N fertilizer and mitigated by supplemental manure and K fertilizer applied to residual P. The decrease in available P levels due to supplemental K application implies that this may serve as a viable alternative to ameliorate soils with excess P levels. / Thesis (PhD)--University of Pretoria, 2010. / Plant Production and Soil Science / unrestricted
10

Integrated evaluation of the capacity and main properties of gleyic luvisols with different fertilization systems / Glėjiškųjų išplautžemių (gleyic luvisols) pagrindinių savybių ir našumo, taikant skirtingas tręšimo sistemas, integruotas vertinimas

Mačiulytė-Mikučionienė, Romutė 31 May 2010 (has links)
In the long-term fertilization experiment on the light sandy loam over moraine clay (Calc(ar)i-Epihypogleyic Luvisols) there were the integrated evaluation of the changes in arable layer done and the estimation of the tendencies and consistent patterns in the productivity of crop plants performed. The obtained research results of the organic, organic-mineral and mineral fertilization impact on the Gleyic Luvisols bulk density, porosity and composition of aggregates, the changes in qualitative composition of organic matter and humus, the phosphorus and it fractions, the soil nitrogen accumulation, the potassium and also the productivity of crop plants in 4-year crop rotation are novel. The performed research also gained the knowledge on the main properties and productivity of the Gleyic Luvisols and on the technology patterns within the soil-fertilisers-plant systems evaluation. The mentioned aspects are actual in the agriculture within the tendencies of decreasing in the extent of fertile soil sources. On the bases of the long-term researches in the Calc(ar)i-Epihypogleyic Luvisols there were either determined the proper fertilisation systems not only for the obtaining of the consistent crop plant productivity but also for the estimating the certain stabilisation and improving of soil use and productivity parameters. The estimated consistents could be further used in performing the fertilisation recommendations, thus, the fertilisation then could correspond the requirements... [to full text] / Daugiamečiame tręšimo bandyme, karbonatingame sekliau glėjiškame išplautžemyje, taikant skirtingas tręšimo sistemas, kompleksiškai ištirti armens pokyčiai bei sėjomainos augalų derlingumo tendencijos bei dėsningumai. Gauti nauji tyrimų duomenys apie organinių, organinių-mineralinių ir mineralinių trąšų poveikį glėjiškųjų išplautžemių tankiui, poringumui ir struktūriniams agregatams, organinės medžiagos ir humuso kokybinės sudėties pokyčiams, fosforo ir jo frakcijų pasiskirstymui, o taip pat jo azotingumui, kalingumui, bei augalų derlingumui keturlaukėje sėjomainoje. Šiais moksliniais tyrimais pagilintos žinios apie glėjiškųjų išplautžemių pagrindines savybes bei našumą, išsiaiškintos technologinių grandžių reikšmė apytakos procesų cikle dirvožemis-trąšos-augalas, kas yra aktualu mažėjant žemės ūkio paskirties derlingos žemės ištekliams. Karbonatingajame sekliau glėjiškame išplautžemyje daugiamečių tyrimų pagrindu išaiškintos tinkamiausios tręšimo sistemos ne tik pastoviam žemės ūkio augalų derliui gauti, bet ir užtikrinančios racionalų šio dirvožemio naudojimą bei jo našumo parametrų stabilizavimą ir gerinimą. Nustatytus dėsningumus galima taikyti rengiant rekomendacijas tręšimui, kurios atitiktų keliamus reikalavimus siekiant užtikrinti taršos mažinimą iš žemės ūkio šaltinių bei palaikytų ir gerintų glėjiškųjų išplautžemių derlingumą.

Page generated in 0.1169 seconds