How do inorganic fertilisers damage soil ?
Plants require ammonium as a source of nitrogen. Ammonium is ammonium irrespective of source i.e. the plant does not distinguish between ammonium produced naturally from nitrogen fixing bacteria or the excreta of soil microorganisms or from ammonium nitrate or sulphate in a fertiliser bag. This is why you can get excellent short term results with inorganic fertilisers. However, inorganic fertilisers are mineral salts and there is a finite amount of ‘salts’ that can be applied to soils before they become detrimental to the microbial population. Likewise, if the plant is sitting in a sea of nutrient, which may or may not be in an accessible form, it will not form the associations with mycorrhizal fungi and other soil microorganisms that it requires to access nutrient naturally and sustainably.
My soil is heavy clay what can I do to improve it ?
The fastest way to improve clay soil is to work sand into the top layer and then apply 2” (5cm) of aerobic compost over the surface followed by 1” – 2.5cm a year thereafter. For lawns apply ½” or 1cm per year and brush it in or apply in several applications. If you are growing vegetables including potatoes, move your potato patch around the entire plot. Potatoes form very strong associations with soil microorganisms, which will make the soil more friable and give it structure, breaking up the clay. Alternatively, create some raised beds and fill with compost rich soil and eventually the clay underneath will slowly break down.
I want to reduce the soil pH what is the best way ?
Biological degradation of organic matter produces a wide range of organic acids; humic and fulvic acid, which naturally lower the pH of the soil over a period of time. If you want to grow ‘acid loving’ plants such as Camellias or Rhododendrons you can apply a small amount of ferrous sulphate to reduce the pH immediately. However, it is better to apply an ericaceous compost or make your own compost from pine needles.
In simple terms, what is a Compost Tea and how does it work ?
A Compost Tea is a microbial soup which contains a diverse range of microorganisms naturally found in a healthy soil. The vast variety of microbes which include, trillions of bacteria, billions of fungi, along with millions of protozoa and nematodes, all of which have a different role and function in the soil ecosystem are essentially ‘shaken’ from the compost in the brewer. These organisms then utilise the food sources added to the brew, the activating nutrients and / or additional nutrient i.e. Seaweed / Fish hydrolysate and proliferate, increasing even further in numbers. This microbial soup is brewed for a minimum amount of time to ensure that the different microorganisms reach their optimal numbers, after which the suspension is filtered into a suitable spraying vessel i.e. watering can, diluted and applied to the plants as desired.
If you are applying Compost Tea to heavily managed soils; soils which have been chemically managed or depleted, then you are adding a ‘fresh’ input of microbes that may already be existing but you are also adding a vast range of microbes which may be deficient in the soils, due to the chemicals and management techniques previously utilised. These new microorganisms with repeated applications and their natural replication will grow in number and their enzymes, toxins and vast number can be used to support plant health and growth. However, if you are adding the Compost Tea brew to a soil which is in a relatively good state, the brew is acting like a probiotic, topping up the diversity – variety, adding a fresh and new input on a regular basis to compensate for those which may have been lost to predation, died or been killed due to the management techniques applied.
The vast diversity of microbes in the soil ensures that no one species gets out of control and is allowed to grow uninhibited. The chemical toxins that the microbes produce, stop and can even kill each other, so they will avoid each other and their population numbers are controlled in this manner. This inhibits one species dominating and becoming a problem to the plant or the other microorganisms. They also predate each other and control numbers in this way. Likewise, they are all producing a vast array of enzymes which can breakdown organic material, making the soil friable and providing it with structure. Similarly, whilst the microbes are undertaking degradation they are releasing in their excretory products, Nitrogen in the form of Ammonium a plant fertiliser. Other soil bacteria perform the nitrogen cycle, releasing forms of plant accessible nitrogen Ammonium and Nitrate. Similarly, many other microbes in the soil undertake the solubilisation of sulphur into sulphates and phosphorous into phosphates which makes these elements accessible to a plant. The soil microorganisms also promote plant health by making the plants own immune system stand on ‘alert’, so you not only have a plant which is being protected and fed, it is also alert and ready for any potential attacks. So, the range of functions completed by the soil biology is astronomical.
What are Mycorrhizal Fungi ?
Mycorrhizal fungi form a symbiotic association with the roots of most known plant species (between 85 – 95%). There four main types; Endo, Ecto, Ericaceous and Orchid, which associate with specific plant families. Endo mycorrhizae are the most common of all mycorrhizae and live within the roots of their hosts. The plant provides the mycorrhizal fungi with protection and carbohydrates, consequently the mycorrhizae considerably extend the plants roots system and provide water, nutrients especially Phosphorous and stress tolerance to the plant. The relationship is advantageous for both parties involved and there are thousands of studies which have recorded the benefits the plant obtains from the association with these fungi.
What is the Soil Food Web ?
The soil food web is the community of organisms living all or part of their lives in the soil. It explains how these soil microorganisms interact with each other, the ecosystem – the soil environment and the plants and higher animals.
A food web illustrates the energy transfer between organisms in the ecosystem. The soil food web is very complex, but the basis of all the energy comes initially from the Sun. Plants use the Sun’s energy to convert inorganic compounds into high energy, organic compounds; utilising Carbon dioxide and minerals and converting these into plant material by the biochemical process of Photosynthesis. Subsequently, senescing and dead plant material is degraded and recycled by saprophytic microorganisms in the soil ecosystem which fuels the entire soil food web.
What is an IPM Program ?
IPM stands for Integrated Pest Management. This is an environmental approach to managing pests. An IPM utilises information and research about the pest’s life cycle and how it interacts with the ecosystem and / or environment; combined with the available control methods. This knowledge is then used to manage the pest and the damage incurred in a way which is the most cost effective and provides the minimal amount of hazard to people, the property and the environment as a whole.
The IPM method can be applied in all settings including agricultural and non-agricultural settings i.e. home and garden, nurseries. Organic food production applies many of the same concepts as a traditional IPM program but uses pesticides used from natural sources i.e. natural bacterial or fungal toxins, competitive exclusion and predation, rather than synthetically produced chemicals.