Water treatment residue (WTR), a by-product of the water treatment process, consists primarily of precipitated hydroxides of the coagulants used in the water treatment process, along with sand, silt, clay, humic compounds, and dissolved organic matter. It is usually disposed of by landfill, a technology with numerous problems that include dwindling landfill capacity, extensive dewatering requirements for the WTRs, high costs of transportation, and potential liability for landfill clean-up. Therefore, land disposal (or land treatment) presents a popular alternative disposal method based on the principle that the physical, chemical, and microbial properties of the soil can be used to assimilate applied waste without inducing any negative effects on soil quality. The objective of this study was to investigate the effects of land disposal of the WTR generated by Umgeni Water, a local water treatment authority, on soil quality. These effects were investigated using depth samples from soil profiles of Westleigh and Hutton soil forms at field trials located at Ukulinga Research Farm, near Pietermartizburg and Brookdale Farm, Howick, KwaZulu-Natal, South Africa, respectively. Four rates of WTR (0, 80, 320, and 1280Mg ha-1 incorporated into the soil) were investigated at both trials, in addition to mulched treatments at rates of 320 and 1280Mg ha-1 at Brookdale only. Sampling of plots was carried out in September 2001 and May 2002, and all treatments were investigated under fallow and grassed cultivation. Laboratory measurements used to assess soil quality included pH, electrical conductivity (EC), organic carbon (QC), and microbial activity using f1uorescein diacetate (FDA) hydrolysis. At both trials in September 2001 WTR-amended plots displayed higher pH in the 0-200mm soil in comparison to the controls, whereas by May 2002 pH had returned to the condition of the controls. Addition of WTR at Ukulinga resulted in higher QC in September 2001, but in May 2002 this was similar to the controls. However, at Brookdale QC was unaffected by WTR. At Ukulinga and Brookdale the effect of WTR on EC was variable, and microbial activity in the soil profile was unaffected by WTR addition. Observations at Ukulinga and Brookdale reflected long term changes (3 and 5 years, respectively) to soil quality following WTR addition. To examine the initial changes in soil quality a laboratory experiment was set up using the field trial soils. Research objectives were also extended to include WTRs from Rand Water (Johannesburg), Midvaal Water Company (Stilfontein), Amatola Water (East London), and two samples from the Faure Water Treatment Plant (near Cape Town). The second Faure sample (Faure2 ) was collected when blue green algal problems were experienced at the plant. The measurements used to investigate these short term effects on soil quality were soil pH, EC, and microbial activity as indicated by respiration rate. Each of the WTRs added to the Hutton and Westleigh soils increased soil pH by varying increments, and the higher the WTR application rate, the higher was the pH recorded. With the exception of the Rand and Umgeni WTRs that clearly increased soil EC, the effect of the otherWTRs on EC was variable. The Faure1 and Amatola WTRs appeared to have no effect on microbial activity, whereas the Umgeni, Rand, Midvaal, and Faure2 WTRs stimulated microbial activity by Day 2 following the addition of WTR, but this had declined by Day 14. As for pH, higher microbial activity was recorded at higher WTR application rates. Changes in microbial community structure of the Hutton soil only, following the addition of WTR were examined using denaturing gradient gel electrophoresis (DGGE) analysis. Community profiles of the different WTRs proved to be markedly different. However, WTR-amended soil retained banding patterns consistent with the control soil indicating that dominant populations in the Hutton soil had been retained. The field trials indicated that long term effects of land disposal of WTR were not detrimental to the measured indicators of soil quality namely, pH, EC, QC, and microbial activity. The laboratory assessments of the short term response of the Hutton and Westleigh soil forms to WTR addition suggested that the tested variables were altered by WTR, but not significantly changed to the detriment of soil quality. Microbial community analysis indicated that the community structure of the Hutton soil was not significantly altered by WTR amendments. Present findings provide no evidence to suggest that land disposal of WTR is detrimental to soil quality. It is therefore regarded as a feasible disposal option although there are some aspects that should be investigated further. These include investigations into rhizosphere/microbial interactions and the feasibility of growing cash crops. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2003.

Eight fertilization treatments were applied in May 1987 to two sugar maple stands. This was followed by soil and foliar sampling and decline evaluation in mid-summer 1987 and foliar sampling and decline evaluation in mid-summer 1988. / Trees selected for sampling purposes on average showed evidence of light to moderate decline. Foliar nutrient status was found to be poor at both sites, with Ca, Mg, K and P at or very near to deficiency levels although foliar molar ratios for Ca/K, Ca/Mg and Ca/Al were well within their respective critical ranges. / Fertilization had significant effects on several elemental concentrations of the soil and foliage at the Entrelacs sites. Effects in general showed an increase in base cation concentrations when those elements were supplied in high enough quantities in the fertilizers. Fertilization had no significant effect on decline levels. / Positive correlations were obtained between soil B horizon levels and foliar Ca, Mg and K and between soil FH horizon levels and foliar K and Al.

Der Anbau von Zwischenfrüchten leistet einen enormen Beitrag zur Erhaltung der Bodenfruchtbarkeit sowie zur Konservierung von Nährstoffen in der Zeit zwischen Ernte der Hauptfrucht und Aussaat der Folgekultur. Zwischenfrüchte sowohl in Reinsaat als auch im Gemenge wurden diesbezüglich auf Feldversuchsanlagen untersucht und ausgewertet. Im Vordergrund stand im Jahr 2013/14 der Einsatz von organischem und mineralischem Stickstoffdünger zur besseren Bestandsetablierung. Der Bericht dokumentiert die Ergebnisse. Zudem werden verschiedene Aussaattechniken ökonomisch bewertet und Anbauempfehlungen gegeben.

Phosphorus uptake cassava (Manihot esculanta Crantz) were tested using on thirty-six plants per plot under dryland conditions at four different sites selected Bioresource group 1 (BRG 1) of northern KwaZulu-Natal of South Africa, which is described as Moist, Coastal Forest, Thorn and Palm veld, exhibiting sub-tropical characteristics. Soils in this region are very low in Phosphorus (P) due to high fixation by iron and aluminium oxides. With its high root yields coupled with efficient nutrients miner, cassava removes large quantities of N, P, K and Mg. With the ever-increasing prices of P fertilizer, which impact on the socio-economic livelihood of smallscale farmers, there is the need to look into improving the P uptake by the crop by alternative means apart from using mineral fertilizers. The objective of this study was to investigate the use of Arbuscular Mycorrhizal Fungi (AMF) to improve P uptake by cassava in agricultural soils. Laboratory studies were conducted at Soil Fertility and Analytical Services in Cedara (Pietermaritzburg). A Latin Square design (LSD) was used. Four treatments used were Untreated (Control), P-fertilizer, AMF, and P + AMF. Correlation and path-coefficient (probabilities) were computed. The P + AMF were significantly (p<0.05) taller than those in P-fertilizer treatment plots but were significantly (p<0.05) similar to those in Control and AMF-treated plots. Percent leaf P was statistically similar at the four sites with grand mean of 0.4%. Adding AMF and P+AMF to the soil substantially increased leaf P concentration to 0.5%. Tubers collected from P+AMF-treated plots were significantly (p<0.05) the longest, while those from Control plots were the shortest. P, and AMF-treated plots increased tuber length relative to the Control. All soil treatments significantly (p<0.05) increased tuber yields over the Control-treatment plots. However, AMF and P+AMF treated plots were significantly higher than P and control plots. This study suggests that using AMF or P+AMF can improve cassava yield as compared P alone or control – untreated cassava plants. Cassava producers in northern KwaZulu- Natal should consider using AMF or P+AMF to optimize tuber yield. A further study into the economic implications of the use of AMF is recommended. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2014.

Forest ecosystems undergo both natural and human induced disturbances. Depending on disturbance type, soil physical and chemical parameters show different response patterns during the recovery phase. An added level of complication is the ecological site types occurring throughout a forested area. The identification of indicators of soil fertility and the successful emulation of a natural disturbance regime were the scope of this research. / The research presented herein took place in the Manitoba Model Forest (MBMF), located in eastern Manitoba, where the natural disturbance regime is wildfire. Timber harvest strategies used in the area are designed to emulate a wildfire (5% retention of standing timber and extensive slash inputs) and clearcut harvesting. The objective of this study was to document changes in forest floor and soil properties prior to and following harvesting, and to compare these properties to those found in a small wildfire that burned in the MBMF in late summer 1998, which serves as a benchmark to the harvest. In the two study areas, both thin mineral soil (5--20 cm) and moderately deep mineral soil (20--100 cm) ecosite types were monitored at four dates over a two year period for soil physical and nutritional response patterns.

Promotion of agroforestry practices in sub-Sahara Africa may help sustain subsistent food and wood production by integrating trees and crops on farmlands to replenish soil fertility and improve crop yield. Using rotational woodlot and pigeonpea intercropping systems in semi-arid Tanzania as case studies, my research screened suitable tree species to increase fuelwood supply and examined mechanisms for reducing tree-crop competition. By adopting nutrient use efficiency (the ratio of biomass yield to nutrient uptake) as a criterion, I found that selecting tree species of low wood nutrient concentrations would minimize nutrient exports by 42 – 60 %, thus reducing soil nutrient depletion while concurrently sustaining local fuelwood supply harvested from rotational woodlots. Currently smallholder farmers cannot afford to replenish soil fertility because of high fertilizer costs. However, 5-year tree fallowing raised soil N and P levels for maize culture as high as those from recommended fertilizer applications. Post-fallow maize yield was also increased significantly over natural fallow practices. Apparently there is a trade-off between yields of maize and fuelwood under rotational woodlot culture providing farmers the choice to proportion tree and crop composition based on priority demands. An alternative practice of intercropping pigeonpea with maize may also rapidly replenish soil fertility as well as enhance maize yield when competitive interactions between trees and crops are controlled. Vector analysis revealed that such interactions suppressed biomass yields of maize and pigeonpea by 30 % and 60 %, respectively, due to limited soil nutrients and/or moisture. Optimizing yields of both crops would require prescribed fertilizer addition when intercropped, but dose rates can be lowered by half under the improved fallow system due to alleviating interspecific competition. My findings form the basis of a plea for greater use of rotational woodlot and pigeonpea intercropping systems in semi-arid areas. I conclude that smallholder farm management of rotational agroforestry systems can be significantly improved by refining tree selection criteria and mitigating nutrient competition between trees and crops to maintain food and fuelwood production.

The soils of Australia have extensive macro and micronutrient disorders varying greatly in their capacities to provide the chemical nutrients essential for plant growth. Assessment of nutrient availability in soils is important in order to maximise fertilizer efficiency and crop yields and to minimise environmental pollution associated with over fertilisation. Nutrient availability has proven difficult to assess due to the complexity of trace element soil chemistry and plant uptake mechanisms. The relatively new method, Diffusive Gradients in Thin Films ( DGT ), provides the potential to become an alternative soil test that could accurately predict nutrient availability. To date, DGT technology has only been designed for separate assessment of anionic and cationic species in waters or soils typically at concentrations characteristic of highly contaminated systems. In this study a new mixed binding gel ( MBL ) was developed capable of simultaneous assessment of cations and anions in a single assay at concentrations more representative of uncontaminated agricultural soils, sediments and waters. The MBL has the potential to eliminate measurement errors associated with very fine spatial scale changes in element concentrations in these environments. The MBL consisted of ferrihydrite and Chelex - 100 cation exchange resin combined together in a binding gel. Results from the MBL were comparable to experiments performed using individual Chelex gels and ferrihydrite gels that have been shown to work successfully for DGT methodology. To facilitate combined analysis of P and cations by ICP - MS, HCl ( 1 M ) was used for gel elution to minimise interferences from [superscript 14] N [superscript 16] OH or [superscript 15] N [superscript 16] O on [superscript 31] P. All elements tested ( Cd, Cu, Mn, Mo, P and Zn ) were bound successfully to the MBL. DGT measurements obtained using the MBL on agricultural soils correlated well ( r ? = 0.95 ) with measurements obtained using pure Chelex and ferrihydrite binding layers. This suggests that the MBL could be used for simultaneous measurement of cationic and anionic element availability in soils. Performance of the Diffusive Gradient in Thin Films ( DGT ) technique was compared with three other common testing methods ( Colwell, Olsen, Resin ) for available soil P in terms of the ability of each to predict wheat, canola, lupin and barley responsiveness to applied P on 21 Australian agricultural soils. DGT accurately predicted plant responsiveness in > 90 % of the soils used. In contrast the other soil testing methods failed to correctly predict plant response to P on numerous occasions. These observations reveal that the DGT technique with the newly developed MBL can predict plant available P on these soils with greater accuracy than other traditional soil P testing methods and could become a useful tool for predicting P fertilizer requirements. The DGT method using the MBL was also used to test Zn deficiency thresholds for canola and wheat in a manufactured soil ( acid washed sand ). DGT successfully determined the threshold for Zn deficiency in this soil, overcoming detection limit issues usually accompanying such low levels of Zn. This method also provides that potential to assess other micronutrients ( Mn, Cu ) and with further modification potentially assess K. Before DGT can become established as an alternative soil testing method, validation of the performance is required under field conditions. This study has shown that it out performs current common soil testing methods in glasshouse conditions but questions still remain if this will be reflected out in the field. / Thesis (Ph.D.)-- University of Adelaide, School of Earth and Environmental Sciences, 2007.

Thesis (Ph. D.)--Ohio State University, 2008. / Title from first page of PDF file. Includes bibliographical references (p. 122-143).

Thesis (M.S.)--Oregon State University, 2008. / Printout. Includes bibliographical references (leaves 46-55). Also available on the World Wide Web.

Diss. (sammanfattning) Umeå : Sveriges lantbruksuniv., 2007. / Härtill 3 uppsatser.