If you work in horticulture, there is no getting away from the fact that sustainability has become a nationwide public priority. Whether this is recyclable plastics or responsibly sourced growing medias, environmental lobbying will have stronger influence on policy, just as we are beginning to see in the latest agricultural bill with ‘public money for public goods’ alongside the most recent letter addressed to the Environment Secretary from environmental groups and celebrity gardener Monty Don aiming to ban total use of peat in all sectors by 2025. The paragraphs below aim to give some depth and figures behind the peat industry, its environmental impacts and what are the potential alternatives. Although horticulture does tend to receive the brunt from opposition groups and media publications, it is worth noting that the vast majority of peat is actually sold into amenity use as soil improvers (AHDB,2015), which is much more suitable for substitution.
What is the current picture?
据估计，泥炭地（毯子沼泽，湿地，森林，森林）估计为407亿公顷（HA），这约为15％，5850万公顷，以某种目的已经排出;通常是城市化和农业，而85％的自然状态仍然存在。有5150万公顷泥炭地坐落在Europe, of which the UK equates for around 2.3 million Ha.
英国Bogs等同于世界上的13％的毯子沼泽，60％的英国泥炭地位于苏格兰。结合当前的围绕多年冻土熔体的问题增加了新闻报道，将泥炭块作为碳汇维持的重要性与其保存的碳汇在一起是全球重要性和强大的政治司机，因为英国承诺将净零碳产量纳入2050年。这bob体彩下下载个bob体彩下下载新闻无所不在，since 2000 total peat extraction in the UK has halved, with less than half of 1% of the total peatland areas in the UK used for extraction.The most recent development on peat extraction has been in Southern Ireland, previously being the key supplier of peat to the UK market. Due to incorrect implementation of EU planning and licensing regulations nearly all peat extraction has been temporarily ceased. This even includes Bord na Mona, the government owned and run Irish Peat Board, who were one of the largest producers of raw peat in Europe (correct as of Nov 2020). It is still uncertain that if the bureaucratic hurdles of planning and licensing are overcome whether there will be the political will to restart. There are an estimated 6,600 jobs directly related and 11,000 indirectly to the peat industry in rural Ireland.
So, who are the remaining main ‘culprits’ for abstracted peat?
Worldwide only 10% of peat extracted is used for horticulture in any form including the hobby market. Of this 10% (roughly 4 million cubic meters) in the UK, 70% is sold into the retail markets for products such as 70Lt bagged John Innes garden mixes (typically containing 50-60% raw peat), 1-2% gets exported and the remaining 28-29% is used for professional use. Although old data, the chart below gives a good indication of the proportional split of peat usage amongst professional users
Figure2。Proportional use of peat in professional Horticulture (AHDB)
Why do we use Peat in horticulture in the first place?
In fact, we do not use peat for everything, coir is the standard for soft fruit production, rockwool for protected salads and some products can be grown hydroponically, but in commercial horticulture we do use it a lot; why? Peat becomes the main component for containerised and growing media mixtures in commercial production when compared with other organic materials due to several physical properties such as high porosity, water holding capacity (WHC), slow degradation ratio, low bulk density and it generally being weed free. It also has good chemical properties like high cation exchange capacity (CEC), easily adjustable pH and low microbiology resulting in a uniform and uniquely reliable substrate.
A balanced argument or an intangible attack on the peat industry?
As abstraction from peatlands is somewhat of an emotive subject, there are social implications to consider. There are much more detrimental recreational industries in regard to CO2 emissions, such as the aviation industry. For example, the same amount of CO2 per Ha will be released per annum from a German peat extraction site as 3 passengers flying one way from London to New York. On the flip side campaigners could argue that an unfettered peat bog absorbs large quantities of CO2 continuously, whereas degraded and commercial bogs do still release large quantities of CO2 emissions that are inarguably negatively impacting the environment.
In practice, drained peatlands located mainly on raised bogs do become major sources of greenhouse gases. Small disruptions to the hydrology of peatlands can upset the balance from carbon sink to carbon source, neighbouring areas of bog within the same hydrological unit can become degraded as a result of the drastically lowered water table. Lowered water tables allow oxygen to penetrate the formerly permanently waterlogged peat allowing rapid decomposition. Well managed peat extraction sites emit on average 3.13t C02/Ha/Yr for German extracted Black Peat and 8.05t C02/Ha/Yr for Lithuanian White Peat. In layman’s terms this is equivalent to driving a medium sized diesel car 12,500 miles per year for 1 Ha/Yr of Black Peat and 32,000 miles per year for 1 Ha/Yr White Peat.
What are the alternatives to Peat?
Bearing in mind most of the peat usage in the UK is for amenity gardener use, most peat use in retail can readily be replaced by more sustainable alternatives. The growing media industry has developed high quality products often using composted green wastes, for most gardening uses the physical and chemical composition of these products would be ‘fit for purpose’.
木质材料的使用和椰壳原料公司reased consistently over the last 10 years, with green compost and bark accounting for similar volumes as a partner for peat reduced mixes. Up to 30% of growing mediums containing wood fibres or green waste materials often have little effect on plant vigour and can in fact improve structural properties of the substrate, helping avoid waterlogging, bacterial infections and fibrous root formation. Too high proportions of woody fibres can cause nitrogen drawdown, reducing N availability to plants and a stunted, pale green crop. It is important to buffer woody fibres with additional Nitrogen to compensate (typically 100g/34% N/per 100L wood fibres/CuM.) Over time the wood fibres will naturally decompose with the assistance of moisture, oxygen and soil microorganisms to be available to the plant, however the benefit will greatly depend on the length of growing cycles.
What do we need to learn about managing the alternatives?
When using peat alternative growing substrates, growers will need to alter their irrigation, nutrition application and stock replenishment practices in accordance with specific materials being used. For example, organic peat free mixes are best used fresh as speed of decomposition and nutrient release is significantly quicker than traditional peat-based mixes. Higher proportions of wood fibres in mixes also require additional nitrogen to maintain the immediately available nitrogen, buffering drawdown into the highly lignified material. Green waste materials offer a great by-product and locally available option for most growers, however there are still limitations to overcome regarding consistency (dependant on time of year and green waste used), contaminants and heavy metals.
As an industry representative, what can be concluded?
We are all responsible for our own reduction in CO2 emissions, whether that be personally or professionally. Most commercial growers even using a “peat” based substrate will have already worked to reduce the peat content by 10-30%. A couple of factors regarding this to remember in respect to CO2 emissions:
1) The alternatives to peat; coir, wood-fibre, bark, green waste are by no means Carbon neutral.
2) The worst thing that can happen to an already commercialised peat bog is ceasing peat extraction.
第一点是显而易见的，无论是来自印度和斯里兰卡的运输资金，还是使用热量和压力来处理它们的一些其他材料，它们都是合理的二氧化碳。让我们看看似乎违反直觉的第二点。肯定是最好的事情是停止提取和重回沼泽吗？一如既往地归结为金钱，目前大多数泥炭提取的国家都有严格的警告，规划到实地意味着生产者必须在20-50年的寿命中占用返回的20 - 50年的百分比，然后管理这些沼泽。如果商业企业被迫立即停止提取，他们可以远离沼泽及其承诺来恢复他们的承诺 - 离开二氧化碳输出高广告信息。
我们还应该记住,泥炭被用于grow plants such as perennials, can capture more CO2 than the amount released from the associated volume of peat extracted. The peat that is being used in commercial horticulture, often is to produce food, something that should be last on the CO2 targeting list, potentially compromising domestic production.
As an industry, if there was to become a comparable media available that could match the qualities of peat, at the correct price point and was much more sustainably sourced then growers would jump at the opportunity to use these products as retail demand and social responsibility would welcome such a change. Although significant investment is being made in finding such materials and cost-effective production methods, the UK is not currently at this stage. We think there is further work that needs to be done in green waste recycling. If green waste constituents can be segregated and mulched more consistently and reliably then we can see increased opportunities to incorporate at a higher rate in certain mixes.