SUSTAINABLE AGRICULTURE Second Edition JOHN MASON National Library of Australia Cataloguing-in-Publication: Mason, John, 1951– . Sustainable agriculture. 2nd ed. ISBN 0 643 06876 7. 1. Sustainable agriculture. 2. Sustainable development. I. Title. 338.16 Copyright © John Mason 2003 All rights reserved. Except under the conditions described in the Australian Copyright Act 1968 and subsequent amendments, no part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, duplicating or otherwise, without the prior permission of the copyright owner. Contact Landlinks Press for all permission requests. Published by and available from: Landlinks Press PO Box 1139 Collingwood Vic. 3066 Australia Telephone: +61 3 9662 7666 Freecall: 1800 645 051 (Australia only) Fax: +61 3 9662 7555 Email: [email protected] Website: www.landlinks.com Cover design and text design by James Kelly Set in 10.5/13 Minion Printed in Australia by BPA Print Group Front cover photograph courtesy of John Mason Contents Acknowledgements v Introduction 1 1 Different things to different people 3 2Sustainable concepts 9 3 Soils 23 4Water management 49 5 Pest and disease control 77 6Sustainable natural weed control and cultivation 101 7 Management 113 8Managing plants – Crops and pastures 129 9Managing plants – Tree plantings and windbreaks 155 10 Managing animals in a more sustainable way 171 11 Understanding products used in sustainable agriculture 191 Appendix 197 Index 203 This page intentionally left blank Acknowledgments Research and Editorial Assistants: Iain Harrison, Peter Douglas, Paul Plant, Andrew Penney, Kathy Travis, Naomi Christian, Mark James, Alison Bundock, Rosemary Lawrence, Peter Douglas, Lisa Flower. Thanks to the following organisations for information supplied: The National Association for Sustainable Agriculture Australia (NASAA) National Farmers Federation Victorian Institute for Dryland Agriculture Australian Wiltshire Horn Sheep Breeders Association Australian Finnsheep Breeders Association Llama Association of Australia The Emu Producers Association of Victoria The Australian Ostrich Association Victorian Department Natural Resources and Environment This page intentionally left blank Introduction First there was subsistence farming. Then there was a technological revolution: develop- ments in machinery and chemicals allowed us to clear and cultivate land faster, feed plants and animals quicker (and grow them faster); and kill pests or diseases quickly. These new- found abilities seemed like a godsend to mankind; and throughout the 20th century we used them to their fullest, generally with little regard to any unforseen repercussions. Gradually, time has revealed a variety of problems caused by this modern agricultural development, including chemical residues affecting plant and animal life on land and in the sea, soil degradation in the form of soil structural decline, erosion, salinity, soil acidification, loss of fertility, nutrient loading of waterways, dams and lakes and more. As we move into the 21st century and concern about our environment grows, there is an obvious move towards more sustainable farming. Sustainable farming is, in essence, concerned with anything that affects the sustain- ability of a farm. You cannot keep farming a property indefinitely if there is a degradation of resources (environmental resources, financial resources, equipment, machinery, materi- als, or any other resources). In the short to medium term, the problem of sustainability is overwhelmingly a financial one; but in the long term, environmental sustainability will possibly have a greater impact on the whole industry than anything else. Why be sustainable? If we can’t sustain agricultural production, we will eventually see a decline in production; hence a decline in food and other supplies. There is no escaping the fact that people need agricultural products to survive: for food, clothing, etc. Science may be able to introduce substitutes (eg synthetic fibres) but even the raw materials to make these will generally be limited. As the world’s population increases (or at best remains stable in some places) demand for agricultural produce increases accordingly. Poorly maintained farms produce less in terms of quantity and quality. Profitability decreases mean that surplus money is no 2 Sustainable Agriculture longer available for repair and improvements. Farm land can become contaminated with chemical residues, weeds or vermin. The amount of vegetation produced (ie the biomass) may reduce, resulting in less production of carbon dioxide, and a greater susceptibility to environmental degradation. We have created a world that relies heavily on technology to produce the food needed to sustain its human population. There is a worldwide dilemma. To abandon modern farming methods could result in worldwide famine but to continue current practices will almost certainly result in long-term degradation of farmland and, eventually, the inability to sustain even current human population levels, without even considering future increases in the human population. Who should be concerned? Everyone needs to be concerned about a decline in farm production potential. The farmer, his family, and workers are always affected first. An unsustainable farm is simply not worth persisting with and any farm which heads this way must eventually be abandoned or rede- veloped to become sustainable. This book is about foreseeing and understanding such problems, and addressing them before it is too late. 1 Different things to different people Sustainable farming means different things to different people, however they all share a common concern in preventing the degradation of some aspect of the farm. Some farmers are primarily concerned with degradation of natural resources (eg their land is becoming less productive). Other farmers may be more concerned about degradation of profitability, which could be due to increased labour or material costs, poor planning, or simply chang- ing conditions in the economy. The causes and the solutions to such problems are different in each situation. Sustainable agriculture is a philosophy: it is a system of farming. It empowers the farmer to work with natural processes to conserve resources such as soil and water, whilst minimising waste and environmental impact. At the same time, the ‘agroecosystem’ becomes resilient, self regulating and profitability is maintained. What to do There are many different ideas about how to be more sustainable. Different people promote different concepts with great vigour and enthusiasm and, in most cases, these concepts will contain something valuable. Many are quite similar in approach, often being variations of a similar theme. Each approach will have its application; but because it worked for one person does does not necessarily mean it will work for someone else. Some of these concepts are explained below. Low input farming systems This approach is based on the idea that a major problem is depletion of resources. If a farmer uses fewer resources (eg chemicals, fertiliser, fuel, money, manpower), farm costs will be reduced, there is less chance of damage being caused by waste residues or overworking the land, and the world is less likely to run out of the resources needed to sustain farming. 4 Sustainable Agriculture Regenerative farming systems This seeks to create a system that will regenerate itself after each harvest. Techniques such as composting, green manuring and recycling may be used to return nutrients to the soil after each crop. Permaculture is currently perhaps the ultimate regen- erative system. A permaculture system is a carefully designed landscape which contains a wide range of different plants and animals. This landscape can be small (eg a home garden), or large (eg a farm), and it can be harvested to provide such things as wood (for fuel and building), eggs, fruit, herbs and vegetables, without seriously affecting the environ- mental balance. In essence, it requires little input once established, and continues to produce and remain sustainable. Biodynamic systems This approach concentrates on mobilising biological mechanisms. Organisms such as worms and bacteria in the soil break down organic matter and make nutrients available to pastures or crops. Under the appropriate conditions, nature will help dispose of wastes (eg animal manures), and encourage predators to eliminate pests and weeds. Organic systems Traditionally this involves using natural inputs for fertilisers and pest control, and tech- niques such as composting and crop rotation. In Australia and many other countries, there are schemes which ‘certify’ produce as being organic. These schemes lay down very specific requirements, including products and farming techniques which are permitted, and others which are prohibited. In Australia, you can find out about such schemes through groups such as the Biological Farmers Association (BFA) or the National Association for Sustainable Agriculture (NASAA). See the Appendix for addresses. Conservation farming This is based on the idea of conserving resources that already exist on the farm. It may involve such things as, for example, identifying and retaining the standard and quality of waterways, creek beds, nature strips, slopes. Hydroponics This approach involves separating plant growth from the soil, and taking greater control of the growth of a crop. This increases your ability