Integrated methods in the vegetable garden

Brief overview of the chapters

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The growing medium

Before starting the first crops, a laboratory analysis of a soil sample is essential in order to determine its physical and biological characteristics and its fertility potential. Important concepts in agronomy and pedology are discussed, including the properties of humus and how it is formed. Absorbent complexes and cation exchange capacity are also studied.

Plant roots do more than just extract nutrients. These plant organs participate in the exchange of nutrients with microorganisms concentrated in a specific area of the soil called the rhizosphere, which must therefore be protected. A detour is taken to analyse the characteristics of resistant soils (also known as suppressive soils) where vegetable plants are less affected by soil-borne pests..

Soils that are too rich in limestone, clay or sand can be corrected with amendments to obtain garden soil that is compatible with the cultivation of many vegetable plants. For amateur gardeners, adding compost is the simplest solution for improving the fertility potential of their vegetable garden. However, this should not be done haphazardly. The choice of organic materials and the composting method are described in order to obtain a healthy compost with the qualities of forest mull.

Some theorists who subscribe to agroecology are convinced that we should no longer wage war on weeds (commonly referred to as “bad grass”). However, weeds compete with vegetable plants for food. Weeds play a role in preserving biodiversity, but they are also carriers of disease and provide a refuge for pests. Although their presence is useful in biodiversity corridors, weeds must usually be eliminated from a crop plot to avoid unmanageable complications, such as when polyphagous pests that can survive in weeds become vectors for incurable diseases. Weeds are also incompatible with certain biocontrol methods such as insect nets, which can significantly reduce the use of pesticides (synthetic or certified organic).

For thousands of years, the spade and plough have been the tools of choice for improving the physical properties of cultivated soil. Now there are other methods of soil cultivation that aim to rebuild soil biodiversity. In some techniques that do not use ploughing, soil cultivation is reduced to a minimum or even abandoned altogether. Each method has its advantages and disadvantages. An article describes why ploughing and pseudo-ploughing, alternated with other shallow tillage techniques, are simple, effective and sufficient methods for maintaining a family vegetable garden, provided that a certain amount of compost is added each year to compensate for natural humus losses.

The rationale behind fertilisation in integrated farming.

Vegetable plants have intense and immediate nutrient requirements during certain periods of their growing cycle. Mineral salt reserves in the soil may be insufficient. Subject to uncontrollable factors, organic fertilisers alone cannot precisely meet the requirements of vegetable plants during the most critical periods. The rationale for fertilising a vegetable garden involves the use of mineral fertilisers, mainly to control nitrogen requirements more precisely, which also has the advantage of significantly reducing the loss of soluble elements (particularly nitrates) into the water table.

Like humans, plants become susceptible to disease when they are poorly nourished. Soil that is well supplied with compost, supplemented by precise nutrient inputs throughout the growing cycle, increases plants’ natural defences against pests, yields and taste quality.

With regard to the use of mineral fertilisers, one article describes how easy it is to cheat in organic farming.

Agroecology and biocontrol techniques

Agroecology is a catch-all term that allows any proponent of pseudoscience and mysticism to claim it as their own. However, it is possible to define scientific agroecology based on well-established scientific data, particularly with regard to ecosystem services, while not forgetting to specify its limitations.

Plant predators known as pests are everywhere in nature. As soon as we grow a variety of vegetables, we give pests the opportunity to thrive. But these pests are also prey for their own predators, who take advantage of the opportunity to multiply. Ultimately, a new balance is established, reducing the impact of pests on crops. Some pests, like their predators, are polyphagous, and both can adapt to other hosts and prey when they cannot find their favourite food. It is interesting to understand the interactions between pests, hosts and pest predators in order to promote natural regulation that benefits crops.

Creating biodiversity corridors to achieve natural pest control is not always an easy goal to achieve. Many factors, often beyond our control, can have a favourable or unfavourable impact on crops. In addition, some pests have no known predators in France and pose a threat to the environment. Examples are given to show how ecosystem services can be optimised for the benefit of vegetable crops. It is then that we discover that the choice of certain host plants planted in an ornamental garden next to a vegetable garden plays an important role in regulating pests. On the other hand, other combinations produce contradictory effects or even encourage the establishment of pests.

One article is devoted to an in-depth critical study of one of the best-known disciplines of agroecology, built on mystical and pseudo-scientific foundations: permaculture.

When ecosystem services fail to regulate the population of a pest, other physical or biological means must be used to protect crops before resorting to plant protection products. In market gardening, active biocontrol methods to combat certain pests have become essential because they are often effective. Insect nets are infallible for protecting vegetable plants against certain pests when these vegetable plants do not need to be pollinated (particularly root vegetables and salads). When this is not enough, it is possible to reduce a pest population by introducing their own predators if these are absent or insufficiently present. This type of treatment aims to control the development of pests. For microbial pests (bacteria, fungi and viruses), crop rotation and varietal selection are often the only more or less effective means of reducing their proliferation.

In recent years, biocontrol plant protection products have emerged, such as bacteria or virus cultures designed to parasitise pests, pheromone traps designed to capture reproductive insects, and biodegradable herbicides derived from living organisms to reduce weed growth. Most of the biocontrol methods and plant protection products approved for non-professional use are studied in detail on a page of this website, with a precise description of their advantages and weaknesses. The most common pests are described, along with the biocontrol methods that should be used to combat them.

Synthetic or organic treatments against pests.

Can we really do without all pesticides? Plants are living beings that can get sick and need to be cared for just like pets. In integrated farming, the use of synthetic and/or organic pesticides is decided upon when all other plant protection methods have failed, and especially when a pest poses a threat to the environment.

50% of French consumers who favour organic products are convinced that pesticides are not used in organic farming. However, Bordeaux mixture, pyrethrins, neem oil and other products are approved for use in organic farming and are far from harmless. Several articles describe their properties and the toxic risks they pose to humans and the environment.

The ban on synthetic pesticides in France from January 2019 for private individuals has caused numerous problems, as these pesticides are essential for reducing “regulated harmful organisms”, which must be controlled in order to protect the environment. Synthetic pesticides are also essential for combating fungal and bacterial diseases, which are often uncontrollable using biocontrol methods. A critical analysis of nettle manure, widely presented as an alternative to synthetic pesticides, reveals some surprising findings.

Amateur gardeners have also been greatly affected by the ban on glyphosate in France since 2019, even though all health agencies worldwide have confirmed that this herbicide poses no carcinogenic risk at the recommended doses. One page describes the circumstances that led to this abusive ban, which is unrelated to the actual risks of exposure, using the example of another substance in the same IARC classification, acrylamide, which many French people consume every day without knowing it when they drink their coffee.

For further information.

List of some websites related to integrated farming, biocontrols and the invasion of pseudoscience in agriculture.