Transformation and loss of excretal nitrogen under winter management systems : a thesis submitted in partial fulfilment of the requirements for the degree of Master of Science in Soil Science at Massey University, Palmerston North, New Zealand

Excreta from cattle animals contain large amounts of nutrients, particularly nitrogen, which could lead to substantial gaseous losses of ammonia and nitrous oxide to the atmosphere, as well as nitrogen leaching. These losses are greatest during wet conditions in winter. However, the situation could be improved through moving cows off grazing paddocks to a stand-off pad or housing system. Therefore, it is necessary to quantify ammonia emissions and evaluate denitrification potential (which leads to emission of N₂O) through various winter management systems in order to determine methods and technologies for efficient and effective mitigation of gaseous emissions. To understand the mechanism of nitrogen transformation and of reduction on gaseous emission from excreta in various winter management systems, a series of incubation studies and a field study were carried out investigating the suitability of several natural materials with absorbent properties, as media to reduce gaseous emission of ammonia and nitrous oxide. The incubation studies were undertaken using cow excreta that consisted of a 1:1 (v:w) mixture of fresh urine and dung collected from a dairy farm. A lab incubation study was conducted using excreta, and excreta amended with soil and sawdust treatments. A further lab incubation study was carried out using different levels of natural materials. The field study consisted of two stand-off pads in which crushed pine bark or sawdust were used as bedding materials. In the incubation study, ammonification was rapid in the case of excreta, compared to excreta amended with addition of natural materials. Whereas nitrification was very slow in the all treatments, only a small amount of nitrate ions could be detected till the end of incubation study. In the incubation study, both soil and sawdust appeared to significantly reduce ammonia emission. In comparison to excreta, amendment with soil (excreta: soil=1:2, w:w) and sawdust (excreta: sawdust=1:2, w:v) reduced ammonia loss by 32.9% and 19.5%, respectively. Excreta amended with a combination of soil and sawdust (1:1:1, w:w:v) was most effective, reducing ammonia emission by 34% under aerobic conditions. Nitrate concentration was found to be the crucial limiting factor affecting the denitrification rate in the incubation studies. When KNO₃ was added to the excreta, the denitrification rate was 43.8µg N₂O-N/g excreta/hour. However, the denitrification rate of the excreta amended with both glucose-C and KNO₃ was 114.4µg N₂O-N/g excreta/hour. Denitrification potential followed: excreta> excreta with sawdust> excreta with soil. On a field-scale stand-off pad, the carbon-rich natural materials pine bark and sawdust were shown to retain nitrogen effectively. After nine months of use, the bark retained 78% of the deposited excreta-N, while the sawdust pad retained 51%. Therefore, it can be concluded that reduction of nitrogen losses can be achieved by using stand-off pad or housing systems (herd homes) which incorporate the use of a carbon rich natural material or soil in winter

Human faeces as a resource in agriculture

Human excreta are a valuable source of nutrients. Their use should be promoted in order to replace some of artificial fertilisers used in agriculture. For the time being, there are many unanswered questions which need to be researched before human excreta can be widely used in plant production

Improving and disaggregating N2O emission factors for ruminant excreta on temperate pasture soils

pre-printCattle excreta deposited on grazed grasslands are a major source of the greenhouse gas (GHG) nitrous oxide (N2O). Currently, many countries use the IPCC default emission factor (EF) of 2% to estimate excreta-derived N2O emissions. However, emissions can vary greatly depending on the type of excreta (dung or urine), soil type and timing of application. Therefore three experiments were conducted to quantify excreta-derived N2O emissions and their associated EFs, and to assess the effect of soil type, season of application and type of excreta on the magnitude of losses. Cattle dung, urine and artificial urine treatments were applied in spring, summer and autumn to three temperate grassland sites with varying soil and weather conditions. Nitrous oxide emissions were measured from the three experiments over 12 months to generate annual N2O emission factors. The EFs from urine treated soil was greater (0.30–4.81% for real urine and 0.13–3.82% for synthetic urine) when compared with dung (− 0.02–1.48%) treatments. Nitrous oxide emissions were driven by environmental conditions and could be predicted by rainfall and temperature before, and soil moisture deficit after application; highlighting the potential for a decision support tool to reduce N2O emissions by modifying grazing management based on these parameters. Emission factors varied seasonally with the highest EFs in autumn and were also dependent on soil type, with the lowest EFs observed from well-drained and the highest from imperfectly drained soil. The EFs averaged 0.31 and 1.18% for cattle dung and urine, respectively, both of which were considerably lower than the IPCC default value of 2%. These results support both lowering and disaggregating EFs by excreta type.This research was financially supported under the National Development Plan, through the Research Stimulus Fund, administered by the Department of Agriculture, Food and the Marine (Grant numbers RSF10/RD/SC/716 and 11S138)

Ecological sanitation - Implementation, opportunities and challenges in Chikwawa

Ecological sanitation (EcoSan) in not a new technology but rather a recognition that human excreta is a valuable natural resource (not a waste to be disposed of), containing plant nutrients which after containment and sanitization can be recycled in agriculture to enhance food production, with minimal risk of pollution of the environment and with minimal threat to human health. Various organizations are implementing EcoSan technologies in Malawi. Chikwawa is a rural district that is currently implementing EcoSan initiatives with resources from the Scotland Chikwawa Health Initiative and the US Ambassador’s Self Help Fund. The benefits from EcoSan are clear. For example, EcoSan systems help reduce the risk of spreading diseases by containing and treating human excreta before collecting it; minimising surface and groundwater contamination and recylcing the nutrients found in excreta and returning them to soil to enhance food production. However, EcoSan poses some challenges in its implementation such as a correct utilization, acceptability and sustainability of the concept

Dietary habits of urban pigeons (Columba livia) and implications of excreta pH – A review

Pigeons are considered to be urban pests, causing untold damage to buildings and potentially impacting the health of humans who come into contact with them or their faeces. Pigeon faecal matter has been implicated in both health impacts and building damage, with the acidity of the excreta playing an important role. Purpose of the Review. This paper is a wide-ranging review of the chemical processes of excreta in the pigeon to aid our understanding of the potential problems of pigeons to buildings and human amenity in the urban space. The natural pH of pigeons is shown to vary based on the bird’s and age as well as reproductive stage. Key findings of the review. The influences of the altered diet between the rock dove (the wild progenitor of the feral pigeon) and the feral pigeon are detailed, indicating that the human-based diet of urban pigeons most likely causes the feral pigeon excreta to be more acidic than the rock dove excreta. This higher acidity is due in part to diet, but also to potential increases in faecal and/or uric acid volumes due to the low quality of humanbased diets. Again, this area of interest is highly data deficient due to the few number of studies and unspecified dietary intake before pH measurement. Implications of the review. Humans are increasingly concerned about pigeon populations (and presumably their accumulated faeces) in the urban space, and control comprises a large part of the interaction between humans and feral pigeons. This review provides a greater understanding of feral pigeons and the true effects of their excreta

Health Risk Perception on Excreta Reuse for Peri-urban Agriculture in Southern Ghana

Access to proper sanitation and disposal sites for faecal sludge is problematic in Ghana, particularly in peri-urban communities. Using a cross-sectional household-level survey data, this study investigates farmers’ perceptions on the health risks of excreta reuse for peri-urban agriculture in Shai-Osudoku district in Ghana. It was found that a majority of the farmers ‘disagree’ that excreta are a waste and are willing to use excreta as fertilizer, albeit a majority ‘agreeing’ perception that excreta reuse can pose health risks. Empirical results from an ordered probit model show that the decision to use excreta as fertilizer is more related to perceptions on excreta as a resource rather than personal and farm characteristics. However, there is some relationship between personal and farm characteristics and perceptions on the health risks of excreta reuse for agricultural purpose. There is also a strong relationship between the perception that excreta are a waste and perceptions on the health risks of excreta reuse. Programmes aimed at promoting improved sanitation should consider the reuse potential of excreta in agriculture, as attested by the farmers as a resource for crop production. There is the need to educate farmers on how excreta could properly be handled and used in agriculture. Other policy options toward risk reducing strategies that involve relevant government institutions and the local media should also be considered to avoid any health hazards associated with excreta reuse in agriculture. Keywords: Sanitation, Excreta reuse, Health risk perception, Peri-urban agriculture, Ghana 1. Introductio

The effect of dietary composition on the water balance of laying hens

12 experiments measured quantitatively the response in excreta moisture of laying hens to dietary concentrations of nutrients and non nutrient components which met or exceeded recommended requirements. Experiments 1-4 measured the response in excreta moisture to dietary sodium, potassium, phosphorus and calcium. Experiment 5 examined the response to 2 sodium salts (bicarbonate or chloride) and for phosphorus x sodium interactions. Linear increases in excreta moisture were produced with increased dietary sodium (Y=719.65+8.12+-1.55X) potassium (Y=570.76+11.95+-2.01X) and phosphorus (Y=723.50+5.59+-0.308X). Dietary calcium concentration had no effect on excreta moisture. Experiments 6-9 measured the response in excreta moisture to dietary crude protein, lysine, methionine and amino acid availability. There were linear increases in excreta moisture with crude protein (Y=410.85+1.32+-0.076X) and lysine (Y=S97.10+0.526+-0.073X). Methionine concentration had no effect on excreta moisture. Reduced amino acid availability gave a linear decrease in excreta moisture (Y=595.93+0.154+-0.048X). Experiments 10-11 measured the response in excreta moisture to dietary resistant starch, differing cereal sources and wheat bran concentration. Linear increases in excreta moisture (Y=679.97+0.170+-0.029X) were produced with increased dietary resistant starch. Cereal source had no effect but wheat bran increased excreta moisture. Experiment 12 measured the response in excreta moisture to dietary fat concentration, saturation and oxidation. There were no effects on excreta moisture. An experiment involving 1440 caged laying hens aimed to describe the change in dirty egg numbers with increases in excreta moisture. Raised excreta moisture gave linear increases in dirty egg numbers (Y=-19.92+0.0367+-0.00430X). A quantitative model was developed using experimental data to attempt prediction of dirty egg numbers from dietary nutrient composition. The nutrient composition of commercial feed samples were fitted and dirty egg numbers predicted. Predicted and commercially determined dirty egg numbers for each feed were incorporated in a regression analysis to validate the model. There was a significant linear relationship between predicted and commercially determined dirty egg numbers. Variation in dietary composition is therefore a major factor effecting excreta moisture and dirty egg output of caged laying hens

Helminth eggs die-off and nutrients : human excreta storage experiment

Are the current practices of handling human excreta for agricultural purposes by farmers in Vietnam good enough?This study set up an excreta storage experiment to research how to inactivate Ascaris lumbricoides eggs and stillmaintain the nutrient value of human excreta

Rethinking Sanitation: Lessons and Innovation for Sustainability and Success in the New Millennium

This report highlights some of the key lessons learned from the past about sustainable sanitation solutions, new thinking emerging from consolidated learning and innovative experimentation on-the-ground, and some of the conditions necessary for success if real improvements in sanitation are to be achieved and sustained in rural and urban areas. Special attention is placed on the shift from supply-led sanitation projects to demand-led and market-oriented projects. The report concludes that with much deeper attention and broadened interest in sanitation, a more realistic view of the complexity, time, resources and effort needed to meet the challenge of large-scale sustainable changes in sanitation at the household level