Characterization of livestock manures biochar and their effect on soil chemical properties and crop growth under glasshouse conditions
- Authors: Dzvene, Admire Rukudzo
- Date: 2017
- Subjects: Biochar Soil fertility
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/9863 , vital:35091
- Description: Biochar is being promoted as an amendment to improve soil properties, crop productivity, and carbon sequestration. In Africa, biochar adoption is hindered by production systems which include technology and feedstocks availability. However, little research has been published on the influence of biochar incorporation on soil chemical properties and early crop establishment. The aim of this study was to characterize biochar from cattle, goat, sheep and poultry kraal manures and their effect on soil properties and crop growth. This was guided by the following specific objectives, (i) to explore the mixed-farming system of Raymond Mhlaba Municipality on availability and utilization of livestock kraal manures (ii) to characterize biochar samples produced from cattle, goat, sheep and poultry kraal manures (iii) to determine the nutrient release patterns of biochars amended in a degraded soil (iv) to determine the effectiveness of converting manure to biochar and cattle manure on maize early development and, (v) to determine the effects of biochar type and application rate on early maize development. The farming system was surveyed to identify quantities of livestock manure, its availability and utilization for soil fertility amendment in cropping in the Raymond Mhlaba Municipality. The emerging results across all the villages revealed that, the mean livestock numbers were, 9.24±8.21 sheep, 9.37±8.15 goats, 7.95±7.66 cattle and 9.02±9.47 chickens. The findings revealed that 94 (82.4percent) of the respondents had access to cropland allocations in the form of outfields and homegardens. However, only 55 (48.2percent) of the respondents were currently cropping their fields. Maize was the most common crop grown followed by butternuts and potatoes. The application of manure by the respondents currently cropping their lands was only 40 (35.1percent) and the quantities used ranged from 210-1450 kg ha-1. The results further showed that the estimated total manure production was 2.9 t year-1, 0.82 t year-1, 0.04 t year-1, and 0.8 t year-1 from cattle, goats, chicken, and sheeps respectively. Drum retort method of slow pyrolysis at a temperature of 400°C was used to produce biochar from cattle, goat, sheep and poultry manure feedstocks. The biochar yields were 63percent, 72percent, 61percent and 83percent on a weight basis for the different feedstocks. The chemical properties of the biochar were significantly different from those of the manure from which they were made. Biochars that were high in Ca and K such as poultry manure biochar and sheep manure biochar indicated higher pH and electrical conductivity values. For instance, sheep manure biochar was (8.1 mS cm-1) and poultry manure biochar was (9.2 mS cm-1). The scanning electron microscopy (SEM) revealed that, the biochars had porous structures ranging from 1.23um to 5.23um in diameter which are important for water conductance and holding capacity. The target soil carbon level to determine the effects of biochar soil incorporation was 2percent and the soil had 0.7percent. Therefore, it was treated with four livestock manure biochars at application rates of 0; 53.2 t ha-1 (CMB); 48.1 t ha-1 (GMB); 50.7 t ha-1 (SMB); and 40.2 t ha-1 (PMB) based on their carbon content to supplement the soil carbon difference. The effect on soil pH was such that SMB increased to 6.44, PMB (6.45), CMB (6.54), and GMB (6.53) relative to the control which did not show any changes. An increase was also observed on Olsen P concentrations (mg P kg-1) which varied with biochar treatments: PMB (6.22), GMB (6.37), SMB (6.44) and CMB (6.44) and were significantly higher than the control. Ammonium-N(NH4+) concentrations (mg NH4+-N) were increased in biochar treatments but, no significant differences were obtained with sampling time. SMB released 7.95 mg kg-1, CMB 7.50 mg kg- 1, PMB 7.46 mg kg-1 and GMB 7.05 mg kg-1, compared to the control 3.23 mg kg-1. Maize growth in soil sampled from farmers fields in cultivation and abandoned treated with biochar without application of inorganic fertilizer did not differ with control (soil only) treatments. However, maize growth in soil treated with biochar and inorganic fertilizer was comparative to manure treatments. This resulted in a follow up study to elucidate the effects of biochar alone and was carried out with cattle, goat, sheep and poultry biochars at five application rates (0, 100, 200, 300, and 400 kg C ha-1) applied to a sandy loam and a clayey loam soil of the Oakleaf and Tukulu soil forms respectively. Post-harvest soil pH, electrical conductivity and Olsen P showed improvements in biochar treatments relative to the control. Improvements in the chemical parameters and plant growth increased simultaneously with biochar application rate. Maize growth was not affected by biochar application at different rates.
- Full Text:
- Date Issued: 2017
Characterization of maize biochars, their effects on soils, early maize growth and effectiveness of fertilizers
- Authors: Pinkson, Sibusisiwe
- Date: 2017
- Subjects: Soil fertility Crops and soils Biochar
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/9974 , vital:35211
- Description: The use of maize biochar in smallholder cropping systems of the Eastern Cape (EC) Province could be a strategy that helps mitigate a common challenge such as poor soil fertility in maize productivity. The current study investigated the following: a) comparison of maize biochars derived from the drum and pit kiln pyrolytic systems as soil amendments; b) effects of maize biochars on soil acidity and extractable nutrients of three arable soil types of the EC Province; c) effects of maize biochars on early maize growth and nutrient uptake; d) effect of maize biochars on the effectiveness of organic and inorganic fertilizers for improved soil quality and maize growth. Maize biochars were produced from two pyrolytic systems namely the pit and drum kiln, each maize biochar type was analyzed with respect to its chemical and physical characteristics to investigate its potential as a soil amendment. Both pyrolytic systems were monitored to identify optimum pyrolytic temperatures reached by each process. Observed peak pyrolytic temperature were 300 °C and 500 °C for the pit and drum pyrolytic systems respectively. Both maize biochar types were alkaline in nature with pH values of 8.36 (H2O) and 7.45 (KCl) and 8.95 (H2O) and 7.82 (KCl) for pit and drum biochar respectively. Electrical conductivity (Ec) of drum biochar was 199 mS /m and that of pit biochar 186 mS /m. Generally, there were no differences in the chemical compositions of the two biochar types. However, in most analysis drum biochar gave higher values in nutrient composition compared to the pit biochar. Moreover, according to SEM analysis both biochar materials consisted of an increase in pore size distribution compared to the original feedstock material. In addition, an increase in nutrient composition in the two biochar types compared to the original feedstock was also observed. In an incubation experiment, potential effects of the two maize biochar types derived from the pit and drum kiln pyrolytic systems on soil acidity and nutrients were investigated on three arable soil types of the EC Province. Three soil types investigated were obtained from the University of Fort Hare (UFH), Phandulwazi (PND) and Msobomvu (MSV). The UFH soil was a sandy loam of the Oakleaf form or Eutric Cambisol, the PND soil was a sandy loam over sandy clay a Haplic Luvisol, while the MSV soil was a clay loam of Westleigh form a Ferric luvisol. Both maize biochar types significantly (p< 0.05) increased soil pH of the three soil types in the incubation study from an average of 4.68- 7.5. Soil pH improvement was in the following order pit biochar> drum biochar> control. Also, the two maize biochar types significantly (p< 0.05) increased the release of cations namely Ca, Mg and Na however, some decrease in nutrient concentrations were observed due to increase in pH levels at the later stage of the study. Biochar incorporation increased extractable P release from 30- 40 mg P/kg to an average range of between 120- 160 mg P/kg across all soil types. A glasshouse study was also conducted investigating the effect of different biochar rates of the two maize biochar types used in the previous studies on early maize growth and nutrient uptake, same soil types were used as those in the incubation study. Biochar was applied at application rates of 0, 100, 200 and 300 kg C/ha of biochar. The glasshouse experiment consisted of two cycles, each with a six week period of monitoring maize seedling growth development. Generally, a significant increase in maize growth parameters such as plant height, stem girth, number of leaves and leaf area increased after biochar additions compared to the control. Both biochars significantly improved maize seedling growth at an application rate of 200 kg C/haHowever, the two biochar types displayed varying impacts on maize growth due to influence of soil type and biochar application rates. Nutrient- uptake of Ca, P, Na and Mg showed to improve at an application rate of 200 kg C/ha for both biochar types showing a 50 percent increase compared to the control. Nutrient- uptake patterns for P, Ca, Mg and Na differed across all soil types, mainly due to changes in pH and Na levels which were influenced by increased biochar concentrations resulting in nutrient deficiency. Another glasshouse experiment aimed at investigating the effects on the two maize biochar types on influencing the effectiveness of both organic and inorganic fertilizers for improved early maize growth and soil productivity. Biochar was applied at an application rate of 400 kg C/ha of biochar, fertilizer was applied at application rates of 0, 10, 20, 30 and 40 kg N/ha and manure at 0, 10, 20, 30 and 40 t/ha respectively. The glasshouse experiment consisted of two cycles, each with a six week period of monitoring maize seedling growth development. In the 1st cycle, manure rate of 40 t/ha resulted in the highest plant height of maize seedlings grown in the glasshouse, biochar type also showed to influence plant height. After the 1st harvest Mg, K and P levels improved at 30 t/ha, Na at 20 t/ha and Ca 40 t/ha of manure. Plant height and stem girth improved at 30 kg N/ha of fertilizer, however, nutrient levels for Ca, K and Mg decreased after the 1st harvest, while Na levels increased. Nutrient uptake was the highest for Mg and Na at 40 kg N/ha while for Ca at 30 kg N/ha of fertilizer. During the 2nd cycle plant height was the highest at 30 t/ha of manure, and effect of manure rate was significant (p<0.05) for number of leaves, plant height and biomass. Whereas, manure rate and biochar type effect were insignificant (p>0.05) for pH, Ec and nutrient uptake changes. Maize seedling showed significant response to fertilizer 40 kg N/ha for most of the growth parameters measured (P<0.05), except for germination percentage. All treatments investigated had no effect on germination percentage. The two biochar types showed significant (p<0.05) effects on soil pH and Ec. Drum biochar was slightly better performing than pit biochar. Results obtained from the various studies suggests that maize biochars derived from the pit and drum pyrolytic systems are potential soil amendments in correcting soil acidity and nutrient deficiency in the EC Province. Both biochar types have shown abilities to improve early maize growth and effectiveness of fertilizers in maize based systems of the EC Province. However, some variations in soil fertility and early maize growth were observed as a result of the soil type response towards the two biochar applications. This could also have risen as a result of a number of factors such as the nutritional composition of biochar material, initial soil type chemical composition, biochar and fertilizer application rates and time taken or period to complete each study. Therefore, further experiments should be conducted to validate these results, preferable having longer periods of study, moreover, field experiments. In addition, investigations on potential feedstock materials such as animal wastes used as biochar in the EC Province can be conducted.
- Full Text:
- Date Issued: 2017
Tillage and crop rotation effects on selected soil properties and wheat yield in a short term field experiment in the Eastern Cape province, South Africa
- Authors: Mtyobile, Mxolisi
- Date: 2017
- Subjects: Crop rotation -- South Africa -- Eastern Cape Cropping systems -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/13414 , vital:39659
- Description: Severe land degradation associated with current conventional production systems have resulted in low production amongst the small scale farmers in the Eastern Cape. Inappropriate management practices cause depletion of organic matter and other essential nutrients leading to a decline in crop productivity. There is growing evidence that conservation agriculture (CA) practices involving no-tillage (NT) coupled with crop rotation and surface residue retention increases soil organic carbon (SOC) and other essential nutrients and therefore has potential to alleviate soil quality deterioration. A study was carried out to investigate the effects of tillage and crop rotation with crop residue retention on selected soil properties and on wheat yield in the Alice Jozini ecotope of the Eastern Cape. Specific objectives were to determine (i) the effect of crop rotation and tillage on soil SOC, NH4, NO3, total N, P, K, Ca, Mg, Zn, soil pH and EC distribution at 0-5 cm, 5 cm -10 cm, 10 cm-20 cm (ii) the effect of crop rotation and tillage on soil bulk density, porosity and on soil water content (iii) the effect of crop rotation and tillage on wheat biomass and grain yield. Treatments were arranged as a split-split plot in a randomized complete block design with three replicates. Tillage treatments included no-tillage (NT) and conventional tillage (CT) and were applied on the main plots while crop rotation treatments were applied as subplots. Crop residue retention treatments were applied as sub-sub plots. The rotational treatments were maize-fallow-maize (MFM), maize-fallow-soybean (MFS), maize-wheat-maize (MWM) and maize-wheat-soybean (MWS). However, the current study focused on tillage and crop rotation treatments under residue retention to give 8 treatments. Data from the field trials showed that NT with residue retention had significantly (p < 0.05) higher SOC, Total N, P, K, Ca and EC relative to CT. The MWS rotation under no-tillage (NT) with residue retention followed by MFS resulted in the progressive improvement in soil nutrient status. The correlations of SOC with various soil nutrients under study showed that the nature of the relationships between SOC and nutrient availability was consistent. Results on soil physical parameters showed that tillage had no significant effect (p > 0.05) on soil bulk density (ρb) and porosity whereas a significant effect on soil water content under NT was observed. Crop rotation had no significant effects (p > 0.05) on soil bulk density, porosity and soil moisture across the tillage treatments. The MWS rotation registered an increase in soil porosity in comparison with the MWM and MFM. Tillage x crop rotation interaction effects were significant (p < 0.05) on the measured porosity and soil water content. Soil bulk density showed negative correlation with soil porosity and soil water content (SWC) whereas porosity had a positive correlation with SWC. On yield parameters, results revealed that no significant (P>0.05) interaction of main effects with respect to wheat biomass and grain yield. Tillage had a significant (P<0.05) effect on wheat biomass only in season 2. Tillage and crop rotation effects were not significant (P>0.05) with regards to grain yield throughout the experimental period. Higher grain wheat biomass and grain yield were found in MWS rotation under NT with surface residue retention although not statistically significant. Correlation analysis revealed that wheat yield was positively correlated to SOC, P, and Total N. Therefore, combination of NT with MWS rotation with residue retention has the potential to significantly improve soil chemical properties and wheat grain yield whereas MWM followed by MWS crop rotation under NT showed an increase in soil porosity and soil water content.
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- Date Issued: 2017
Crop rotation and crop residue management effects under no till on the soil quality of two ecotopes in the Eastern Cape, South Africa
- Authors: Isaac, Gura
- Date: 2016
- Subjects: Crop rotation Crops and soils Soil fertility
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/2934 , vital:28144
- Description: The degradation of soil quality due to undesirable farming practices has reached alarming scales in the Eastern Cape and this has had negative repercussions on soil productivity and the environment in general. There is growing evidence that conservation agriculture (CA) practices involving minimal mechanical disturbance, maintaining permanent surface cover and embracing diverse crop rotations increase soil organic carbon (SOC) and therefore has potential to mitigate soil quality deterioration. A study was carried out at two sites located in two ecotopes to investigate the effects of crop residue retention and crop rotations in a no till system on overall soil quality using the Soil Management Assessment Framework (SMAF) as the soil quality assessment tool. The CA study trials were laid out in 2012 at two different locations, one at the Phandulwazi Agricultural High school within the Phandulwazi Jozini ecotope and the other one at University of Fort Hare Research Farm within the Alice Jozini ecotope. The experiment was laid out as a split-split plot arrangement in a randomized complete block design with three replicates. Tillage treatments were applied on the main plots while crop rotation treatments were applied as subplots. Crop residue retention treatments were applied as sub-sub plots. The rotational treatments were maize-fallow-maize (MFM), maize-fallow-soybean (MFS), maize-wheat-maize (MWM) and maize-wheat-soybean (MWS). The initial assessment of the overall soil quality of the two ecotopes using the SMAF soil quality index (SQI) revealed that the soils at the Alice site were functioning at 80% while the soils at the Phandulwazi site were functioning at 79 percent of their optimum capacity. The slight difference in the soil quality of the two ecotopes could be attributed to their different soil organic C contents where the Alice Jozini ecotope had significantly higher soil organic C contents than the Phandulwazi Jozini ecotope. After 3 years of continuous treatment application, crop residue retention significantly improved most of the measured soil quality parameters. Generally across the sites, more soil organic C, microbial biomass C (MBC), ß-glucosidase (BG) activity, mineral N, extractable P and K, Cu, Zn, Mn, Fe, and macro-aggregates were recorded in treatments where crop residues were retained. Crop rotations alone did not have a significant impact on most of the measured soil quality indicators. The crop rotations influenced significantly the availability of mineral N across the two sites, highlighting the importance of using a legume in rotations on available N for the subsequent crops. Most of the measured soil attributes were not significantly influenced after 3 years of continuously applying combined treatment of CA components. Mineral N (NO3 + NH4), K, Zn and Fe were significantly impacted on by the interactions of CA components at the Phandulwazi site, while N, Cu, Zn and Mn were significantly increased at the Alice site. Low response of SOC to combined CA treatments in the short-term prompted the need to examine treatment effects on individual soil carbon fractions. The interaction of crop rotation and residue management techniques were significant on the fine particulate organic matter – C fractions and microbially respired C. These soil C fractions were more sensitive to short-term treatments of combined CA components than SOC and MBC, therefore they can be used as short-term indicators of CA effects on SOM. Soil organic carbon, MBC, extractable P and K, soil pH, EC, b, AGS (aggregate stability) and BG activity were measured and the Soil Management Assessment Framework (SMAF) used to calculate soil quality index (SQI) values for each treatment. The combination of the crop rotations with crop residue retention showed the potential to significantly improve SQI values in the long term. The highest soil quality improvement at both sites was achieved by the maize-wheat-soybean (MWS) rotation with crop residue retention.
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- Date Issued: 2016
Effects of BT Maize (MON810) crop and its residues on selected soil biological properties and N and P release in a sandy loam soil from Alice, Eastern Cape, South Africa
- Authors: Landzela, Besule
- Date: 2013
- Subjects: Bacillus (Bacteria) , Bacillus thuringiensis , Corn -- Planting , Biomass , Plant proteins , Enzymes , Soil fertility , Crop residue management
- Language: English
- Type: Thesis , Masters , MSc Agric (Crop Science)
- Identifier: vital:11870 , http://hdl.handle.net/10353/d1007542 , Bacillus (Bacteria) , Bacillus thuringiensis , Corn -- Planting , Biomass , Plant proteins , Enzymes , Soil fertility , Crop residue management
- Description: There are apprehensions that genetic modification of maize with Bacillus thuringiensis (Bt) may have negative effects on soil biodiversity, ecosystem processes and functions. This study aimed at determining the effect of Bt maize crop, Bt maize residues and its genetic modification on microbial biomass carbon (MBC), selected enzyme activities, vesicular arbuscular mycorrhizal (VAM) fungi and N and P release patterns. The study was conducted under field, glasshouse and laboratory conditions. In 2010/2011 season, four maize cultivars; DKC 61-25B (Bt), DKC 61-24 (non-Bt), PAN 6Q-321B (Bt) and PAN6777 (non-Bt) were planted. Determination of MBC, enzyme activities and fungal spore count was done at 42, 70, and 105 days after planting (DAP). A loam soil amended with Bt or non-Bt maize leaf residues from a study of 2009/2010 season was incubated to investigate effects of Bt maize residues on MBC and soil enzyme activities. Leaf residues of Bt and non-Bt maize cultivars (DKC 61-25B, DKC 61-24, PAN 6Q-321B and PAN6777) were used and soil without residues was used as a control. Samples were collected at 7, 28 and 56 days of incubation (DOI). An incubation study was also carried out in the laboratory to determine the effect of Bt maize residues (i.e. leaf, stem and root) and its genetic modification on N and P release patterns. Residues of DKC 61-25B, DKC 61-24, PAN 6Q-321B and PAN6777and soil without residues as a control were incubated in the laboratory. After destructive sampling at 0, 7, 14, 28, and 56 DOI, N in the form of NH4-N and NO3-N and P mineralisation were determined. Amendment of soil with residues enhanced MBC (p < 0.05) at all the sampling dates. For example MBC increased from 95 in the control to 146.3 mg/kg in the DKC 61-25B treatment at the end of the glasshouse trial. In the field DKC 61-25B had 9.1 mg/kg greater MBC than DKC 61-24, while PAN 6Q-321B had 23.9 mg/kg more MBC than PAN6777 at the end of the trial. However, no differences (p < 0.05) were observed in enzyme activities under field and glasshouse conditions except for dehydrogenase that had greater activity where DKC 61-25B and PAN 6777 were grown. There were no differences between the type of residues (Bt and non-Bt) on enzyme activities tested. However, differences were observed among the sampling dates. No effects of Bt maize crop on fungal spore count were observed. Similarly no differences were observed in leaf, stem and root tissues composition between Bt and non-Bt maize cultivars. Net N and P mineralisation from Bt maize cultivars did not differ from that of non-Bt maize cultivars. However, differences were observed among the cultivars. The results of this study suggested that Bt maize with Bt MON810 event can be grown in the central region of the Eastern Cape (EC), South Africa without affecting MBC, soil enzyme activities, VAM, and release of N and P nutrients from its residues.
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- Date Issued: 2013
Effect of BT maize on earthworm activity, silage quality and residue decomposition in the central Eastern Cape
- Authors: Kamota, Agathar
- Date: 2011
- Subjects: Corn -- South Africa -- Eastern Cape , Corn -- Silage , Bacillus thuringiensis , Earthworm culture , Biomass , Plant proteins
- Language: English
- Type: Thesis , Masters , MSc Agric (Crop Science)
- Identifier: vital:11863 , http://hdl.handle.net/10353/413 , Corn -- South Africa -- Eastern Cape , Corn -- Silage , Bacillus thuringiensis , Earthworm culture , Biomass , Plant proteins
- Description: There are concerns that genetic modification of maize with Bacillus thuringiensis may influence its structural and chemical composition which, together with the Cry1Ab proteins, may affect agro-ecosystem processes and feed quality. This study was aimed at investigating the expression of Cry1Ab protein in leaves, stems and roots of Bt maize and the effect of genetic modification (MON810) on activity of earthworms, silage quality and decomposition of residues in the field. In 2009/10 four maize cultivars; DKC61-25B, DKC61-24, PAN6Q-321B and PAN6777 were planted. Expression of Cry1Ab in leaves, stems and roots was analyzed at 6, 8, 10 and 12 weeks after planting (WAP). Earthworms were also sampled from the same treatments at 6, 9 and 18 WAP. Two silage experiments were conducted using maize cultivars, DKC80-12B and DKC80-10 produced in the 2008/09 season and DKC61-25B, DKC61-24, PAN6Q-321B and PAN6777, produced in 2009/10. The silage was sampled at 0, 2, 4, 8, 15 and 42 days in 2008/09 and 0, 8 and 42 days in 2009/10 and analyzed for Ash Free Dry Matter, Crude Fiber, Neutral Detergent Fiber, Acid Detergent Fiber, Acid Detergent Lignin, Crude Protein and Total Digestible Nutrients. Two litter-bag decomposition studies were also carried out (i) in 2008 (surface applied) using maize cultivars DKC80-12B, DKC80-10 and DKC6-125 residues and (ii) in 2009 (soil incorporated) using DKC75-15B, CRN3505, PAN6Q-321B v and PAN6Q-121. Ash-free dry matter and Cry1Ab protein were measured throughout the incubation time. There were no differences between DKC61-25B and PAN6Q-321B in terms of expression of Cry1Ab in leaves, stems and roots over time. The Cry1Ab expression levels were in decreasing order: leaves > stems > roots. No effects of Bt maize on earthworm numbers and biomass were observed. There were no differences in all silages parameters except NDF and ADF, which were higher in the Bt maize silage than that of the non-Bt maize from the 2008/09 season. The Cry1Ab levels were essentially not reduced during ensiling. The maize residues (both Bt and non-Bt maize) degraded to similar levels, either when surface-applied or incorporated into soil but soil-incorporated residues decomposed faster than surface-applied ones. Cry1Ab degraded as the plant matrix decomposed. The findings suggested that maize genetically modified with the Bt MON810 event can be grown in the Central Eastern Cape without affecting earthworm numbers and biomass, silage quality and decomposition of maize residues.
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- Date Issued: 2011
Improving sanitization and fertiliser value of dairy manure and waste paper mixtures enriched with rock phosphate through combined thermophilic composting and vermicomposting
- Authors: Mupondi, Lushian Tapiwa
- Date: 2010
- Subjects: Compost , Vermicomposting , Manures , Biodegradation , Waste paper -- South Africa -- Eastern Cape , Thermophilic bacteria , Fertilizers
- Language: English
- Type: Thesis , Doctoral , PhD (Soil Science)
- Identifier: vital:11961 , http://hdl.handle.net/10353/411 , Compost , Vermicomposting , Manures , Biodegradation , Waste paper -- South Africa -- Eastern Cape , Thermophilic bacteria , Fertilizers
- Description: Thermophilic composting (TC) and vermicomposting (V) are the two most common methods used for biological stabilization of solid organic wastes. Both have their advantages and disadvantages but the proposed method of combining composting and vermicomposting (CV) borrows pertinent attributes from each of the two methods and combines them to enhance overall process and product qualities. Dairy manure and waste paper are two wastes produced in large quantities at the University of Fort Hare. The study was carried out to address the following specific objectives, to determine (i) the effectiveness of combined thermophilic composting and vermicomposting on the biodegradation and sanitization of mixtures of dairy manure and paper waste, (ii) an optimum precomposting period for dairy manure paper waste mixtures that results in vermicomposts of good nutritional quality and whose use will not jeopardize human health, (iii) the effectiveness of phosphate rock (PR) in increasing available P and degradation and nutrient content of dairy manure-paper vermicomposts, (iv) the physicochemical properties of vermicompost substituted pine bark compost and performance of resultant growing medium on plant growth and nutrient uptake. Results of this study revealed that wastes with a C: N ratio of 30 were more suitable for both V and CV as their composts were more stabilized and with higher nutrient contents than composts made from wastes with a C: N ratio of 45. Both V and CV were effective methods for the biodegradation of dairy manure and paper waste mixtures with C: N ratio of 30 but the latter was more effective in the biodegradation of waste mixtures with a C: N ratio of 45. The combinination of composting and vermicomposting eliminated the indicator pathogen E. coli 0157 from the final composts whereas V only managed to reduce the pathogen population. iv A follow up study was done to determine the effects of precomposting on pathogen numbers so as to come up with a suitable precomposting period to use when combine composting dairy manure-waste paper mixtures. Results of this study showed that over 95% of fecal coliforms, E. coli and of E. coli 0157 were eliminated from the wastes within one week of precomposting and total elimination of these and protozoan (oo)cysts achieved after 3 weeks of precomposting. The vermicomposts pathogen content was related to the waste’s precomposting period. Final vermicomposts pathogen content was reduced and varied according to precomposting period. Vermicomposts from wastes precomposted for over two weeks were less stabilized, less humified and had less nutrient contents compared to vermicomposts from wastes that were precomposted for one week or less. The findings suggest that a precomposting period of one week is ideal for the effective vermicomposting of dairy manure-waste paper mixtures. Results of the P enrichment study indicated an increase in the inorganic phosphate and a reduction in the organic phosphate fractions of dairy manure-waste paper vermicompost that were enriched with PR. This implied an increase in mineralization of organic matter and or solubilization of PR with vermicomposting time. Applying PR to dairy manure-waste paper mixtures also enhanced degradation and had increased N and P contents of dairy manure-waste paper vermicomposts. Earthworms accumulated heavy metals in their bodies and reduced heavy metal contents of vermicomposts. A study to determine the physicochemical properties of vermicompost substituted pine bark compost and performance of resultant growing medium on plant growth and nutrient uptake was done. Results obtained revealed that increasing proportions of dairy manure vermicomposts in pine bark compost improved tomato plant height, stem girth, shoot and root dry weights. v Tomatoes grew best in the 40 to 60% CV substituted pine bark and application of Horticote (7:2:1 (22)) fertilizer significantly increased plant growth in all media. Progressive substitution pine bark with dairy manure vermicomposts resulted in a decrease in the percentage total porosity, percentage air space whilst bulk density, water holding capacity, particle density, pH, electrical conductivity and N and P levels increased. Precomposting wastes not only reduced and or eliminated pathogens but also improved the stabilisation and nutrient content of dairy manure waste paper mixtures. The application of PR to dairy manure waste paper mixtures improved the chemical and physical properties of vermicomposts. Earthworms bio-accumulated the heavy metals Cd, Cr, Cu, Pb and Zn whilst the contents of these in the vermicomposts declined. It is, therefore, recommended that dairy manure waste paper mixtures be precomposted for one week for sanitization followed by PR application and vermicomposting for stabilization and improved nutrients contents of resultant vermicomposts. Substitution of pine bark compost with 40 to 60 % PR-enriched vermicompost produced a growing medium with superior physical and chemical properties which supported good seedling growth. However, for optimum seedling growth, supplementation with mineral fertilizer was found to be necessary.
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- Date Issued: 2010
Tillage and crop rotation impacts on soil, quality parameters and maize yield in Zanyokwe Irrigation Scheme, South Africa
- Authors: Njaimwe, Arnold Ngare
- Date: 2010
- Subjects: No-tillage , Soil mechanics , Soils -- Quality , Cover crops , Corn -- Irrigation
- Language: English
- Type: Thesis , Doctoral , PhD (Soil Science)
- Identifier: vital:11962 , http://hdl.handle.net/10353/460 , No-tillage , Soil mechanics , Soils -- Quality , Cover crops , Corn -- Irrigation
- Description: Intensive tillage and monoculture cropping practices reduce soil C accumulation hence increasing soil vulnerability to chemical, physical and biological degradation. This study focussed on enhancing biomass production of wheat and oat winter cover crops as a means of increasing C sequestration in the low organic C soils of the central part of Eastern Cape Province. The specific objectives were (i) to evaluate the short-term effects of no till and cereal-fallow based crop rotations on; soil organic matter related parameters, pH and electrical conductivity, (ii) soil bulk density, water retention and aggregate stability, (iii) soil microbial biomass C and N, mineralizable N, soil respiration, and dehydrogenase enzyme activity, (iv) grain yield, soil nutrient concentration (N, P and K) and their uptake by maize, and (v) to identify soil parameters with high sensitivity to tillage under maize-fallow-maize, maize-wheat-maize and maize-oat-maize rotational cover cropping practices. The experiment was laid out as a split-plot arrangement in a randomized complete block design with 4 replicates. Tillage treatments (CT and NT) were applied on the main plots which measured 8 × 18 m while crop rotation treatments were applied in the subplots which measured 8 × 6 m. The rotation treatments were maize-fallow-maize (MFM), maize-wheat-maize (MWM) and maize-oat-maize (MOM). Weed control in NT plots involved preplant application of glyphosate to control mainly the grass weeds while post emergence weed management was done using Atrazine (485 atrazine and 15 g l-1 triazines). Initial weed control in CT plots was achieved through ploughing to a depth of 20 cm followed by disking while post emergence weed iii management was done by hand hoeing. Soil parameters measured were; (i) particulate organic matter (POM), soil organic carbon (SOC), total nitrogen (TN), pH and electrical conductivity (EC), (ii) soil bulk density (b), moisture at field capacity (FC), aggregate mean weight diameter (MWD) determined by fast wetting (FW), slow wetting (SW), mechanical breakdown by shaking (MB) and the stability index (SI), (iii) soil microbial biomass C (MBC) and N (MBN), mineralizable N (MN), soil respiration (SR), and dehydrogenase enzyme activity (DHEA). No-till increased POM and TN compared to CT in Lenye and Burnshill, respectively. The MWM and the MOM rotations increased TN relative to the MFM rotation in Lenye. The MWM and MOM rotations enhanced SOC relative to MFM in all sampled soil depths at Burnshill and similar observations were made under MOM rotation in the 5-20 cm depth in Lenye. The MWM and MOM rotations tended to depress soil pH relative to the MFM rotation in both sampled soil depths in Lenye while NT reduced soil pH relative to CT on the surface soil layer in Burnshill. Soil EC and pH varied with depth across tillage practices but both parameters remained within the ideal range for successful crop production over the study period. Soil stability index (SI) and aggregate MWD determined by FW, SW and MB were higher in Lenye compared to Burnshill. The MOM rotation enhanced the SI relative to MFM and MWM rotations at both sites. Scanning electron microscope (SEM) showed that more organic C was incorporated into the soil under NT and MOM rotation compared to CT and MFM rotation which had few organic coatings on the soil particles. Microbial properties varied with plant biomass input as influenced by tillage and type of rotational cover crop at both sites. Like in other past studies, NT showed higher levels of MBC, MBN, NM and SR at the soil surface layer compared to CT in Burnshill. No till increased MN iv relative to CT in both sampled soil depths in Lenye and resulted in higher DHEA compared to CT in Burnshill. The MOM rotation increased MBC, MBN, MN relative to MFM rotation especially within surface soil layer. Similar observations were made with respect to MN and SR in both sampled soil layers at Lenye. By contrast, the DHEA was higher under the MFM relative to the MWM and MOM rotations in Lenye but similar under the MFM and MOM rotations in Burnshill. Maize grain yield was not affected by both tillage and crop rotations but varied with cropping season. Comparable grain yields observed under the two tillage practices with similar fertilizer application rates indicated the advantage of NT over CT in saving on labour costs in maize production without compromising yields. High plant biomass retention under NT relative to CT contributed to high soil N and P levels under the former compared to the latter tillage practice especially on soil surface layer at both study sites. Principal component analysis (PCA) revealed that soil chemical and biological parameters closely linked to organic matter, namely SOC, MN, MBC and MBN showed the highest sensitivity to tillage and crop rotation treatments. Soil aggregate MWD determined by SW and b were the physical parameters which were highly altered by agronomic management practice. The MWM and MOM rotations were clustered together and clearly separated from the MFM rotation and this observed trend only applied to the 0-5 and 5-20 cm depths in Lenye site only. No till, MWM and MOM rotations enhanced POM, SOC and TN relative to CT and MFM rotation suggesting these practices have greater potential to improve soil chemical properties compared to intensive tillage and maize monoculture based production practices. Reduced soil b under MOM rotation and improved SI under NT compared to MFM and CT, respectively v indicate that these practices have the potential to improve degraded soils. Although not significantly different, NT values for MBC, MBN, MN, SR and DHEA were higher compared to CT indicating the potential of the practice to improve soil biotic activity relative to conventional tillage practices. No till enhanced surface soil nitrate N and extractable P compared to CT at both sites revealing the long-term potential of NT in improving the supply of these essential plant nutrients compared to CT. Principal component analysis showed that SOC, MN, K, P, MBC, MBN, soil aggregate MWD determined by SW and b were the most sensitive parameters to tillage and crop rotations. Therefore, these parameters could constitute the minimum data set for assessments of the impact of selected CA practices on soil quality attributes.
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- Date Issued: 2010
Bioconditioning and nitrogen fertility effects of selected cyanobacteria strains on two degraded soils in the Eastern Cape Province, South Africa
- Authors: Maqubela, Mfundo Phakama
- Date: 2009
- Subjects: Nostoc , Cyanobacteria , Soil fertility -- Testing , Soils -- Nitrogen content , Cyanobacteria -- Biotechnology
- Language: English
- Type: Thesis , Doctoral , PhD (Soil Science)
- Identifier: vital:11959 , http://hdl.handle.net/10353/558 , Nostoc , Cyanobacteria , Soil fertility -- Testing , Soils -- Nitrogen content , Cyanobacteria -- Biotechnology
- Description: Some cyanobacteria strains have biofertilization and bioconditioning effects in soils. The objective of this study was to identify cyanobacteria with potential to improve the N fertility and structural stability of degraded soils and evaluate their effectiveness in soils of the Eastern Cape, South Africa. Isolation and characterization of the indigenous cyanobacteria strains with desirable properties was first to be undertaken because their effects are known to differ from strain to strain. Cyanobacteria strains 3g, 3v, and 7e were identified from 97 strains isolated from selected soils. Nostoc strains 3g and 3v had greater ability to produce exocellular polysaccharides (EPS) but low potential to fix atmospheric N2 (4.7 and 1.3 nmol C2H4 μg chl-1 h-1, respectively). On the other hand, strain 7e had the highest capability to fix atmospheric N2 (16.1 nmol C2H4 μg chl-1 h-1) but had the least ability to produce EPS. Evaluation of the strains was done in glasshouse studies starting with Nostoc strain 9v isolated from a Tanzanian soil, followed by the indigenous strains isolated from soils in Hertzog and Qunu, South Africa. Inoculation was done by uniformly applying cyanobacteria on the surface of potted soils at a rate of 6 g m-2. First harvest and soil sampling took place after six weeks, and the top 25 mm of the soil was mixed, replanted, and sampled again after a further six weeks (second harvest). Inoculation with Nostoc strain 9v increased soil N by 40 percent and 17 percent in Guquka and Hertzog soils, respectively, and consequently increased maize dry matter yields by 40 and 49 percent. Soil C increased by 27 percent and 8 percent in Guquka and Hertzog soils, respectively, and this increase was significantly associated with that of soil N (R2 = 0.838). Higher contents of soil C, soil N and mineral N, however, were found in non-cropped soils. Scanning Electron Microscopy (SEM) revealed coatings of EPS on soil particles and fragments of non-cropped inoculated soils, with iii other particles enmeshed in networks of filaments, in contrast to cropped and/or non-inoculated soils. The proportion of very stable aggregates was increased by inoculation but cropping with maize reduced the aggregate stability. Inoculating Hertzog soil with indigenous strains 3g and 7e increased the nitrate N in the first cropping by 49 percent and 69 percent respectively, in cropped soils. In the second cropping increases in mineral N were 41 percent and 43 percent in 3g and 7e inoculated soils, respectively. Maize dry matter yields were higher on inoculated soils both in the first and second harvest in response to the improved N status of the soil. Increases in aggregate MWD in cropped soil as determined by fast wetting, mechanical breakdown and slow wetting were 85 percent, 33 percent, 33 percent, respectively, for 3g inoculation, 64 percent, 41 percent, and 41 percent, respectively, for 7e inoculation and 60 percent, 24 percent, 50 percent for inoculation with 9v. In non-cropped soil, increases in MWD as determined by fast wetting, mechanical breakdown and slow wetting were 11 percent, 0 percent, 7 percent, respectively for 3g inoculation, 21 percent, 11 percent, and 7 percent, respectively for 7e inoculation, and 25 percent, 36 percent, and 19 percent for strain 9v inoculation. Scanning electron microscopy observations, which were confirmed by chemical results, revealed that inoculated soils had high EPS and filaments that encouraged soil aggregation and improved aggregate stability. Results of this study show that cyanobacteria strains isolated and selected for their ability to fix atmospheric N2 and produce EPS improved the fertility status and aggregate stability of degraded soils from South Africa.
- Full Text:
- Date Issued: 2009
Evaluation of the effective micro-organisms (EM) on soil chemical properties and yield of selected vegetables in the Eastern Cape, South Africa
- Authors: Ncube, Lindani
- Date: 2008
- Subjects: Greenhouse management -- South Africa -- Eastern Cape , Butternut -- South Africa -- Eastern Cape , Microorganisms -- South Africa -- Eastern Cape , Sustainable agriculture -- South Africa -- Eastern Cape , Organic farming -- South Africa -- Eastern Cape , Tomatoes -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc Agric (Horticultural Science)
- Identifier: vital:11886 , http://hdl.handle.net/10353/86
- Description: Effective microorganisms (EM), a commercial concoction of microbes that includes yeasts, fungi, bacteria and actinomycetes, have been found to be effective in enhancing crop growth by a number of scholars. It is registered in South Africa, but it had not been thoroughly investigated. The present study investigated the effects of EM on growth, yield and quality of tomato (Lycopersicon esculentum Mill), butternut (Curcurbita moschata) and Swiss chard (Beta vulgaris), along with selected soil properties. In field-grown tomato it was observed that the application of EM caused a significant increase in the number of fruits at seven weeks after transplanting. However, plants treated with EM alone, or EM in combination with other amendments, subsequently produced lower yields owing to an outbreak of early and late blights which affected them the most severely. Combined applications of EM with organic amendments improved plant N content and increased soil N content above initial levels. The application of compost resulted in soil N and P concentrations higher than those of the control presumably due to nutrients being slowly released from the compost material. In a follow up greenhouse trial EM application had a negative effect on tomato leaf dry matter yield, number of leaves, number of trusses, fruit yield and number of fruits. The negative effects of EM were ascribed to N immobilization by the EM that could have resulted in reduced N availability to plants. The lower number of fruits associated with EM application resulted in improved average fruit weight of tomatoes grown in the greenhouse, possibly as a result of more assimilates being partitioned to the few fruits EM application also had a negative effect on field grown butternut as reflected by lower total yield, lower marketable yield and lower first grade yield. The results were attributed to immobilization of N induced by application of EM, and to the inability of EM to control pumpkin fly that attacked very young fruit, resulting in their failure to develop or resulting in the down grading of mature fruits. The application of EM alone had a positive but non significant effect on the yields of both the first and second harvests of Swiss chard. However, when applied with compost or goat manure, a non significant negative effect on yield was observed. When applied with inorganic fertilizer, EM had no effect on yield but tended to increase the uptake of nitrogen by Swiss chard. Though goat manure had a narrower C: N ratio than compost, it did not result in greater EM effectiveness as had been hoped. However, goat manure had a more positive effect on soil properties than compost. It increased the N, P, and K contents of the soil and resulted in a narrower C: N ratio of the soil compared to compost. Generally, the results of the four trials conducted with three different crops indicated that EM had inconsistent effects on crop performance.
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- Date Issued: 2008