Nutrient Flows and Balances in Mixed Farming Systems in Madagascar

Mixed farming systems are still prevalent in sub-Saharan Africa. In these systems, the recycling of nutrients through crop-livestock integration (CLI) practices is crucial for the sustainability of soil fertility and crop production. The objective of this study was to analyze nutrient (N, P, K) flows and balances of mixed farming systems to assess CLI contribution to the performance of those systems. We hypothesized that more intensive farms had a better nutrient balance at the farm level, and that improved biomass management methods improved their nutrient balance. Nine farms in the Madagascar highlands were selected, some corresponding to poor traditional farms with only draft cattle; some small or medium-sized, more intensive farms with a dairy herd; and some of the latter with some improvement to management methods of livestock effluents (manure composting, liquid manure collection). The nutrient balance of the farming systems was determined, and performance indicators were calculated at both farming, livestock, and CLI levels. Results showed that nutrient recycling through CLI is significant in the functioning of the systems studied, contributing primarily to circulating nutrient flows (up to 76%) and leading to greater efficiency and productivity. Nutrient flows resulting from these practices mainly concerned animal feeding (higher than 60% of nutrient flows), even if manure management was central for crop fertilization and that manure remained a desired animal product of these types of farms (up to 100% of animal products). Large negative balances of N and K (up to 80% of inputs) were observed in traditional livestock systems with draft cattle. They were smaller (39–68%) in more intensive dairy farms. Composting of manure did not decrease negative balances, whereas their magnitude was significantly reduced by the collection of liquid manure (19% for N; 42% for K). Better management of biomass at the farm level, in particular the collection of liquid manure, seemed to substantially reduce nutrient losses in MFS.

Emissions of carbon dioxide and methane from dairy cattle manure

There is an increasing interest in reducing production and emissions of greenhouse gases to combat global warming. Greenhouse gases can be produced through animal production operations. One of the major sources of greenhouse gases emitted from the animal farming is dairy cattle barns. This study measured the CH4 and CO2 emissions from dairy cattle manure decomposition trapped inside the static chambers through anaerobic digestion process by bacteria and at regular intervals by focusing on animal age and manure storage method. Samples were analyzed using gas chromatography for the estimation of CH4 and CO2 emissions. Four Friesian cows were used representing two stages of cow age (3 and 10 years old) and 1 kg of fresh manure samples were collected (feces and mixture of feces with urine). It was found that CH4 and CO2 emissions produced by cattle at the age of 3 years were higher than age of 10 years. In addition, gases emitted from fresh slurry feces were higher than liquid manure for both ages (3 and 10 years). This is due to the fact that the organic matter degradation in the feces and amount of fresh slurry feces is twice the amount of fresh slurry feces used in the liquid manure, as well as the organic matter in the manure mass for the age of 3 years is higher than for the age of 10 years. The findings from this study can provide information for improving manure management practices in animal farms.

Response Curves for Ammonia and Methane Emissions From Stored Liquid Manure Receiving Low Rates of Sulfuric Acid

Addition of sulfuric acid (H2SO4) to liquid dairy manure (slurry) reduces methane (CH4), nitrous oxide (N2O), and ammonia (NH3) emissions. There is interest in understanding how gaseous emissions respond to decreasing rates of acidification, to determine economically optimum application rates. Acidification rates were tested ranging from 0 to 2 g sulfuric acid (H2SO4) L−1 slurry in six meso-scale outdoor storage tanks, each filled with 10.6 m3 slurry and stored for 114 d. Results showed that the rate of acidification for maximum inhibition of CH4 and NH3 emissions varied markedly, whereas N2O reductions were modest. Reductions of CH4 increased with acid rate from 0 to 1.2 g L−1, with no additional response beyond >1.2 g L−1. In contrast to CH4, inhibitions of NH3 showed a linear response across all rates, although reductions were ≤ 30%. Thus, higher acidification rates would be required to achieve greater NH3 emission reductions. Our findings indicate that achieving >85% NH3 emissions reductions would require 4 × more acid than achieving >85% CH4 reductions. Decisions on optimum H2SO4 rates will depend on the need to mitigate CH4 emissions (the primary greenhouse gas emitted from stored liquid manure) or reduce NH3 emissions (which is regulated in some regions). These results will help develop guidelines related to the potential costs and benefits of reducing emissions through acidification.

MODELING THE INFLUENCE OF THE LIQUID MANURE MOISTURE ON THE LEVEL OF ITS SANITARY AND EPIDEMIOLOGICAL LOAD

Проблема и цель. Одним из перспективных факторов энергетически эффективного и экологически безопасного использования ресурсов является цифровизация процессов, позволяющая прогнозировать и оценивать состояние системы в зависимости от её исходных свойств. Утилизация бесподстилочного навоза тесно связана с этим фактором. Известно, что безопасно использовать энергетический потенциал бесподстилочного навоза невозможно без подавления имеющихся в нём патогенных биомасс, а выбор оптимального подхода к обеззараживанию во многом зависит от их исходной концентрации. Соответственно, исследование влияния технологических свойств бесподстилочного навоза – температуры, рН, влажности на число колониеобразующих единиц патогенов в нём является актуальной задачей для науки и техники. Целью настоящего исследования является разработка элементов системы цифровизированной оценки уровня экологической нагрузки животноводческих предприятий в зависимости от уровня влажности образуемых отходов на примере свиного бесподстилочного навоза. Методология. Использованы методы статистической обработки экспериментальных данных с учётом модели ферментативной кинетики патогенных биомасс в свином бесподстилочном навозе, произведена оценка достоверности полученных математических зависимостей. Результаты. Получены исходные данные в виде квадратичных уравнений, позволяющие прогнозировать уровень исходной концентрации колониеобразующих единиц (КОЕ) бактерий группы кишечных палочек (ОКБ), аэробных спорообразующих микроорганизмов (СПМО), стафилококков (СТФ), яиц аскариды, трихоцефала, эзофагоста, фасциола, личинок стронгилята, клещей (АСК), цист простейших и ооцистэймерий (ЦИО), а также энтерококков (ЭНТ) в зависимости от влажности бесподстилочного навоза. Заключение. На основании полученных математических зависимостей разработан элемент системы цифровизации оценки уровня экологической нагрузки, создаваемой свежим бесподстилочным навозом. Развитием полученных результатов будет являться разработка базы данных закономерностей технологических свойств бесподстилочного навоза и их влияния на концентрации патогенной биомассы, как элемента программной среды цифровизации и прогнозирования санитарно-эпидемиологической нагрузки, создаваемой им. Problem and purpose. One of the promising factors of energy efficient and environmentally safe use of resources is the digitalization of processes, which makes it possible to predict and evaluate the state of the system depending on its initial properties. Utilization of liquid manure is closely related to this factor. It is known that it is impossible to safely use the energy potential of liquid manure without suppressing the pathogenic biomasses present in it, therefore, the choice of the optimal disinfection approach largely depends on their initial concentration. Accordingly, the study and formalization of the influence of the technological properties of liquid manure of temperature, pH, humidity on the number of colony-forming units of pathogens in it is an urgent task for science and technology. The purpose of this study is to develop elements of a system for digitalized assessment of the level of environmental load of livestock enterprises depending on the level of moisture in the generated waste, using the example of liquid pig manure. Methodology. Methods of statistical processing of experimental data were used, taking into account the model of enzymatic kinetics of pathogenic biomasses in liquid pig manure, the reliability of the obtained mathematical dependencies was assessed. Results. Initial data were obtained in the form of quadratic equations that allow predicting the level of the initial concentration of colony-forming units of bacteria of the Escherichia coli group, aerobic spore-forming microorganisms, staphylococci, ascaris eggs, trichocephalus, esophagostomas, fasciolas, strongylate larvae, ticks, cysts of protozoa and oocysts of the eimer from the moisture of liquid manure. Conclusion. On the basis of the obtained mathematical relationships, an element of the digitalization system for assessing the level of the environmental load created by fresh liquid manure was developed. The development of the results obtained will be the creating of a database of other regularities of technological properties of liquid manure and their influence on the concentration of pathogenic biomass, as an element of the software environment for digitalization and forecasting of the sanitary and epidemiological load created by it.

Structural and Informational Model of Increasing the Biotransformation Intensity of the Liquid Fraction of Pork Liquid Manure

A method for intensifying environmentally friendly biotransformation of a liquid fraction of pork liquid manure into a bioorganic fertilizer based on a structural information model, which is the initial data for the development of digital solutions, is described. The theory of potential efficiency is used as the basic tool of the structural and information model. An information model of a digitalized control system is proposed as a basis for the development of software systems and intelligent control solutions.