The production of biogas, which is regarded in many countries as a by-product of an efficient system of energy production, has become in China a comprehensive, controlled method of waste disposal, recycling resources, supplying energy and fertilizer and improving rural health, as the digesting of wastes in a closed container kills many of the pathogens responsible for common human diseases.There are already approximately seven million biogas pits in opertion, with Sichuan (Szechuan) province leading the country in a movement to extend the practice throughout the countryside. This manual describes in detail how to build the pit, and covers a full range of designs to suit various soils from sandstone to sheer rock. It also includes a description of how the original manual was used.

First published in 1926, this classic survey, which includes nearly 250 photographs, examines the traditional farming methods of the densely populated lands of China, Korea and Japan and shows how fertility can be maintained over many centuries through conserving and utilizing natural resources. In the Introduction, the author notes: ‘The United States as yet a nation of but few people widely scattered over a broad virgin land with more than twenty acres to the support of every man, woman and child, while the people whose practices are to be considered are toiling in fields tilled more than three thousand years and who have scarcely more than two acres per capita, more than one-half of which is uncultivable land.’ Researchers and scholars in the fields of human geography, regional studies and earth sciences, as well as social and economic history will welcome this landmark study being returned to print.

Bioenergy is renewable energy obtained from biomass-any organic material that has stored sunlight in the form of chemical energy. Biogas is among the biofuels that can be obtained from biomass resources, including biodegradable wastes like manure, sewage sludge, the organic fraction of municipal solid wastes, slaughterhouse waste, crop residues, and more recently lignocellulosic biomass and algae. Within the framework of the circular economy, biogas production from biodegradable waste is particularly interesting, as it helps to save resources while reducing environmental pollution. Besides, lignocellulosic biomass and algae do not compete for arable land with food crops (in contrast with energy crops). Hence, they constitute a novel source of biomass for bioenergy. Biogas plants may involve both high-tech and low-tech digesters, ranging from industrial-scale plants to small-scale farms and even households. They pose an alternative for decentralized bioenergy production in rural areas. Indeed, the biogas produced can be used in heaters, engines, combined heat and power units, and even cookstoves at the household level. Notwithstanding, digesters are considered to be a sustainable technology that can improve the living conditions of farmers by covering energy needs and boosting nutrient recycling. Thanks to their technical, socio-economic, and environmental benefits, rural biogas plants have been spreading around the world since the 1970s, with a large focus on farm-based systems and households. However, several challenges still need to be overcome in order to improve the technology and financial viability.

This is a newly edited revision of Albert Howard's important text on organic farming and gardening, and the central role of humus in maintaining soil health and fertility. THE SOIL AND HEALTH is a detailed analysis of the vital role of humus and compost in soil health - and the importance of soil health to the health of crops and the humans who eat them. The author is keenly aware of the dead end which awaits humanity if we insist on growing our food using artificial fertilisers and poisons. Albert Howard (1873-1947) was one of the leaders of the British organics movement in the mid-twentieth century. He was the first westerner to document and publish research on traditional techniques of agriculture, including Indian and Chinese farming and management of the soil. "Agriculture is the fundamental industry of the world and must be allowed to occupy the primary position in the economies of all countries." - Albert Howard CONTENTS 1 - Soil Fertility and Agriculture 1.1 The operations of Nature The life of the plant The living soil The significance of humus The importance of minerals 1.2 Systems of agriculture Primitive forms of agriculture Shifting cultivation The harnessing of the Nile Staircase cultivation The agriculture of China The agriculture of Greece and Rome Farming in the Middle Ages 1.3 Soil fertility in Great Britain The Roman occupation The Saxon conquest The open-field system The depreciation of soil fertility The low yield of wheat The Black Death The Industrial Revolution and soil fertility The Great Depression of 1879 The Second World War 1.4 Industrialism and the profit motive 1.5 The intrusion of Science 2 - Disease in Present-day Farming and Gardening 2.1 Diseases of the soil Soil erosion The formation of alkaline land 2.2 The diseases of crops 2.3 Disease and health in livestock 2.4 Soil fertility and human health 2.5 The nature of disease 3 - The Problem of Manuring 3.1 The origins and scope of the problem The phosphate problem and its solution The reform of the manure heap Sheet-composting and nitrogen fixation The utilisation of town wastes 3.2 The Indore Process - Some practical points - The New Zealand compost box - Mechanisation - The spread of the Indore Process 3.3 The reception by scientists