Saturday was the first day of a two day workshop at a local educational farm. The topic is sustainable agriculture, below is some information from about this. I do not claim to be an expert and am happy to respond to any comments or answer any questions anyone wishes to post.
Firstly, Sustainable - means that you can continue to do something over a long period of time using a set/or consistent amount of energy input. Sustainable agriculture then specifically refers to farming practices that do minimum long term damage to the environment whilst providing maximum yield and profit for the farmer. Meaning that the farmer can continue to grow produce on the land and the land can continue to support the growth. Sustainable agriculture does not have to be purely organic but they do tend to due to the energy that is required to manufacturing chemical pesticides and fertilisers.
Modern or Industrial agriculture is not considered sustainable as it is an input-->output system rather than a cycle. When land is first cleared and crops planted the soil is in typically (Mediterranean climate) good health and contains good quantities of organic matter and nutrients that support the development of crops. However, upon harvest the plants are removed from the land taking with them valuable nutrient that were once in the soil. The soil becomes nutrient deficient and chemical fertilisers are then input to enable growth of crops.
In addition to the loss of nutrients, soil also beings to lose its structure as topsoil can be eroded by wind and/or rain run off and heavy machinery can compact the soil. This means that further fertiliser may be needed to compensate for the loss of topsoil and mechanical ploughing may be needed to loosen the soil to allow growth.
Another issue is with pests as the mono-culture crops (one type of plant) also require large input of chemical pesticides. Having a large area of just one species of plant will attract and cause a boom in pest populations. It is basically like a kid in a candy store or finding an oasis in the desert. People start growing a pests food source on mass in one place then it is no wonder that the pest organism would move in and intend to stay. A loosing battle then begins to eradicate the pest population. Using chemical pesticides over a long period of time can then lead to the pest developing genetic resistance to the chemical and then further chemicals being needed to kill the pest.
In a sustainable set-up the goal is to make a cyclic system where soil health is the priority so that crops can continue to grow on the land long term. The main way to do this is to minimise soil disturbance and maximise return of organic matter and nitrogen to the soil. It is about recognising the inputs and outputs of the system and making the process more efficient so that nature does the work itself without requiring manufactured chemical additions.
However, soil health on its own is not enough to create a sustainable system as there is still the issue of pests and disease. Crop diversity (growing many species of plants together) and companion planting is one way to deal with this problem. It involves having different crop or non-crop plants planted in the same area so that large smorgasbords of pest food are not on offer and thus avoiding plague proportions of pests. Also, if you learn to plant as companions then some planting combinations will stop certain pests from attacking or minimise damage inflicted upon crop plants. For example: planting Rosemary with cabbages will repel cabbage flies. Crop diversity can also be of benefit to the farmer financially as not all their effort is invested in one plant that could have a poor season and income can potentially become year-round as plants could fruit or mature at different times meaning a more frequent sale of products.
One problem or limitation with sustainable practice is that it is labour intensive and hard to apply to large scale farms. This means for our food production to become sustainable we would need food to be produced on a more local level and for more people to be actively involved in the production of the worlds food supply.
Firstly, Sustainable - means that you can continue to do something over a long period of time using a set/or consistent amount of energy input. Sustainable agriculture then specifically refers to farming practices that do minimum long term damage to the environment whilst providing maximum yield and profit for the farmer. Meaning that the farmer can continue to grow produce on the land and the land can continue to support the growth. Sustainable agriculture does not have to be purely organic but they do tend to due to the energy that is required to manufacturing chemical pesticides and fertilisers.
Modern or Industrial agriculture is not considered sustainable as it is an input-->output system rather than a cycle. When land is first cleared and crops planted the soil is in typically (Mediterranean climate) good health and contains good quantities of organic matter and nutrients that support the development of crops. However, upon harvest the plants are removed from the land taking with them valuable nutrient that were once in the soil. The soil becomes nutrient deficient and chemical fertilisers are then input to enable growth of crops.
In addition to the loss of nutrients, soil also beings to lose its structure as topsoil can be eroded by wind and/or rain run off and heavy machinery can compact the soil. This means that further fertiliser may be needed to compensate for the loss of topsoil and mechanical ploughing may be needed to loosen the soil to allow growth.
Another issue is with pests as the mono-culture crops (one type of plant) also require large input of chemical pesticides. Having a large area of just one species of plant will attract and cause a boom in pest populations. It is basically like a kid in a candy store or finding an oasis in the desert. People start growing a pests food source on mass in one place then it is no wonder that the pest organism would move in and intend to stay. A loosing battle then begins to eradicate the pest population. Using chemical pesticides over a long period of time can then lead to the pest developing genetic resistance to the chemical and then further chemicals being needed to kill the pest.
In a sustainable set-up the goal is to make a cyclic system where soil health is the priority so that crops can continue to grow on the land long term. The main way to do this is to minimise soil disturbance and maximise return of organic matter and nitrogen to the soil. It is about recognising the inputs and outputs of the system and making the process more efficient so that nature does the work itself without requiring manufactured chemical additions.
However, soil health on its own is not enough to create a sustainable system as there is still the issue of pests and disease. Crop diversity (growing many species of plants together) and companion planting is one way to deal with this problem. It involves having different crop or non-crop plants planted in the same area so that large smorgasbords of pest food are not on offer and thus avoiding plague proportions of pests. Also, if you learn to plant as companions then some planting combinations will stop certain pests from attacking or minimise damage inflicted upon crop plants. For example: planting Rosemary with cabbages will repel cabbage flies. Crop diversity can also be of benefit to the farmer financially as not all their effort is invested in one plant that could have a poor season and income can potentially become year-round as plants could fruit or mature at different times meaning a more frequent sale of products.
One problem or limitation with sustainable practice is that it is labour intensive and hard to apply to large scale farms. This means for our food production to become sustainable we would need food to be produced on a more local level and for more people to be actively involved in the production of the worlds food supply.
