India Langley of LettUs Grow outlines the different approaches to controlled environment agriculture and explains how the company's no pressure aeroponic growing system has overcome many of the problems associated with more traditional aeroponic systems .

In a just‐in‐time model, retailers rely on suppliers to send items as they are needed instead of storing them in large stock rooms. Because of this, problems with deliveries or sudden changes in demand (such as panic buying) lead to empty shelves as there is no back‐up stock. The closures and lockdowns enforced due to the current pandemic, have created logistical bottlenecks that ripple across these long chains.

This problem is being acutely felt up and down the country by both retailers and consumers. While there is still food within the supply chain, many do not have access to it as it is just not getting to the retailers fast enough. The problem is not the amount of food produced globally, it is the logistical hurdle of getting that food to those who need it.

Controlled environment agriculture

To reduce the risk of food shortages, immediate action must be taken to minimise disruptions and to bolster local food networks. Controlled environment agriculture (CEA) is one of the most effective ways to improve local food security. Particularly in urban and periurban spaces, where open field farming is not possible, CEA farms can grow produce closer to the consumer.

Controlled environment agriculture (CEA) is one of the most effective ways to improve local food security.

CEA is exactly as it sounds: a form of farming where plants are grown within a controlled environment. As well as allowing growers to produce food in places where they would not have been able to do so before, CEA optimises the use of resources, such as water, land, fertiliser and labour. CEA comes in many forms from greenhouses to vertical farms; the three main technologies employed are hydroponics, aquaponics and aeroponics.

Hydroponics is a method of growing plants without soil. Instead, the plant's roots hang down into nutrient‐rich water. Plants grown hydroponically have been shown to grow 25‐30% faster than those grown in soil. Hydroponics can be used in both greenhouses, making use of sunlight, or in vertical farms, under LED lighting.

Aquaponics is, in essence, a form of hydroponics but instead of dissolving nutrients in water, the wastewater from aquaculture is used. Excretions from aquatic animals accumulate in the water. This effluent‐rich water is then fed into a hydroponic system where the by‐products are broken down into nitrates that are then absorbed by the plants as nutrients. The cleaned water is then recirculated back to the aquaculture system.

Aeroponics is similar to hydroponics but instead of the roots hanging down into a nutrient solution, they hang down into a nutrient‐dense mist. Plants grown within an aeroponic system have shown significantly faster growth rates than those grown in hydroponic systems.

By contrast, hydroponic systems immerse plant roots in a nutrient rich solution of water, which is either maintained as a narrow film or flooded and drained to expose the plant roots intermittently to air and then water. In such systems, the roots can use only the oxygen dissolved in the nutrient solution, the concentration of which is minimal due to its low solubility, roughly 8mg per liter at room temperature. At the increased temperatures at which most CEA facilities are operated, this gaseous deficit is exacerbated. The roots’ respiratory demand for oxygen roughly doubles for each 10x rise in temperature (up to 30x). The plant's metabolism increases with photosynthesis which drives the crop's oxygen demand up even further.

At concentrations of less than 3mg of oxygen per litre of water, root growth is significantly inhibited. In these hypoxic conditions, plant growth is limited by this reliance on anaerobic respiration, which is up to 15 times less efficient than aerobic respiration. As well as slowing growth, anaerobic respiration can result in the creation of unwanted fermentation products: ethanol, alanine and lactate in some plants.

Aeroponics itself is not new. It was originally developed in coordination with NASA in the 1980s with the intention of growing food for astronauts in space. These early design aeroponic systems worked by forcing nutrient rich water through numerous tiny valves embedded in pressurised tubing to create an aerosol. The resultant mist was then deposited on the plant roots.

These pressurised systems, called High Pressure Aeroponics, or HPA, are useful on small scale projects but are difficult to scale into a productive CEA farm. One common problem in these systems is nozzle clogging. As the water moves through the system, it picks up plant debris and the nutrient solution can calcify to form something similar to the limescale in a kettle, both of which can block the small holes within the nozzles.

In an aeroponic system, clogging of the nozzles represents a danger to the plants under cultivation. As the only water available to the plants is in the mist, if these holes are blocked for as little as three‐six hours under lights, the plants can wilt or even die. Because of this, the grower has to check and perhaps change the nozzles often. This flaw in the system has prevented growers accessing the full benefits of aeroponics on a large scale.

New technology for indoor farming

LettUs Grow is an indoor farming technology provider based in Bristol, UK. The company has designed a patent‐pending indoor farming system for greenhouses and vertical farms to address global food security and sustainability concerns. These indoor farms need no fertile land to operate, use zero pesticides and provide a consistent, predictable and climate‐resilient food supply all year round.

The technology is centred around two core products: a novel aeroponic system and an integrated farm management software called Ostara. Using this system, we have shown significant growth rate increases across a range of crops, compared to current indoor farming methods, such as hydroponics. This is achieved by using 95% less water and fertiliser than traditional open field farming and 30% less water than hydroponic systems.

Ostara automates and controls the whole indoor farm, whilst collecting data on plants, overseeing inputs to crop growth and allowing farmers to trace crops from seed to sale, making operations more efficient. These two innovative technologies are combined inside an insulated growing chamber to create a self‐contained farm, the LettUs Grow Farm Module.

In side by side trials with industry standard hydroponics, we have seen growth rate increases of as much as 150% for early stage crops. The reason for this increase is the improved access to oxygen for the plant roots. Because the roots are suspended in air, instead of soil or water, they have access to atmospheric levels of important gases, such as oxygen. This allows far greater levels of root gas exchange than in traditional hydroponic systems.

Advantages of no pressure aeroponic systems

LettUs Grow's no pressure aeroponic systems have been designed to have all the advantages of aeroponics without the system complexity. We have completely removed nozzles, so there is nothing to clog and break; this also makes the system wipe‐clean and easy to operate.

The system allows for greater precision of nutrient application, as the quantity of mist produced can easily be fine‐tuned for each grow bed, rather than the more centralised distribution of water in many hydroponic systems. This means irrigation can be controlled on a crop by crop basis. The level of nutrients, water and gases provided to crops can be tailored to the plant's individual requirements and adjusted depending on the plant's developmental stage.

The accessibility of roots in this system means that plants are less prone to mould or other infections. As aerosol is only applied sparingly to crop roots, the rooting medium remains dry and using UV sterilisation and proper filtration within this process ensures that the chances of pests or disease outbreaks occurring are kept to a minimum. This means it is not necessary to expose plants to pesticides, making the system healthier for the plant, but also for consumers and the environment. Increasingly growers make use of integrated pest management (IPM) principles to utilise biological control measures, which further protects both crops and customers without the need for pesticides.

Traditionally, one of the biggest overheads for CEA farms has been the cost of energy; in the case of vertical farms it can contribute up to 40% of the total business costs. The Ostara software platform can be used to mitigate both the financial and environmental impacts of this demand by linking directly to the agile energy tariff Vertical Power, offered by renewable energy supplier Octopus Energy for Business. It is the only energy tariff designed specifically for CEA farms. The Vertical Power tariff tracks energy pricing in real‐time, making it perfect for smart management of operations to reduce costs. By integrating an agile energy tariff into Ostara, indoor farmers can adjust their plants’ growth cycles to align with lower energy costs, saving them money, reducing their impact on the planet and making the most of an automated system that links to the wholesale energy market. LettUs Grow has modelled the savings for a ‘typical’ vertical farm on a Vertical Power tariff – seeing up to 12% cost reduction.

CEA farms have the potential to significantly disrupt the current fresh produce supply chain while conveying benefits to the growers in the process.

CEA farms have the potential to significantly disrupt the current fresh produce supply chain while conveying benefits to the growers in the process. In temperate climates, such as the UK, a global food network is used to keep seasonal produce, such as strawberries, tomatoes and salad items, on the shelves from January to December.

In CEA farms, the weather does not affect the produce as it is always a balmy summer's day with perfect growing conditions inside. By situating these farms close to the consumer, you can reduce food miles and strengthen communities’ regional food security by reducing reliance on lengthy supply chains.

Having the ability to produce a steady, predictable supply of fresh food helps to alleviate the ‘paradox of plenty’ for farmers. While in many markets, having a stable demand for goods is an asset, in agriculture it can lead to problems for the grower.

The paradox of plenty is caused when good growing conditions and a surplus of produce lead to a reduced income for the grower due to an inflexible demand for that produce. Because the market is saturated with lettuce, for example, the price of lettuce falls and this abundant harvest results in a reduction of the growers income.

Conclusions

LettUs Grow was founded to enable anyone, anywhere in the world, to grow fresh produce near its point of consumption.

Having the ability to produce a steady, predictable supply of fresh food helps to alleviate the ‘paradox of plenty’ for farmers.

Our mission has hardly ever felt as urgent as it does today. As a result of the coronavirus pandemic, the UK's delicate just‐in‐time food supply chain has come under close scrutiny. Currently, the UK only produces roughly 50% of the food it consumes, which leaves it vulnerable to shocks in the global supply chain.

It is unlikely that CEA farming can be rolled out fast enough to dramatically impact the current coronavirus crisis in the short term, but the pandemic has shone a bright spotlight on wider concerns about the weaknesses within our food system.

It may be the wake‐up call needed to address wider food security concerns, such as those posed by soil loss – a third of the world's soils are severely degraded due to agriculture, or the impacts of climate change.

Climate change is already affecting our food system. Extreme weather events, such as the 2018 heatwave or the floods of 2019 devastate farmers’ ability to grow crops and they are becoming increasingly commonplace.

Computer modelling by the Met Office has shown that these weather events are now 30 times more likely due to man‐made climate change. In a world where atmospheric CO₂ had not risen above pre‐industrial levels, these events would happen once every 200 hundred years. They are now predicted to be one in every eight.

In areas impacted by these changes to the weather, CEA farms could prove to be a vital piece of infrastructure to ensure a stable food supply for consumers and to protect the livelihoods of farmers around the world.

India Langley, LettUs Grow, Bristol, UK

Email india.langley@lettusgrow.com

Web lettusgrow.com

中文翻译：

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内部知识

LettUs Grow的印度Langley概述了控制环境农业的不同方法，并解释了该公司的无压力航空植物生长系统如何克服了许多与传统航空系统有关的问题。

在实时模型中，零售商依靠供应商按需发送商品，而不是将其存储在大型储藏室中。因此，交货问题或需求突然变化（例如紧急购买）会导致货架空缺，因为没有备用库存。由于当前的大流行而实施的关闭和封锁造成了物流瓶颈，这些瓶颈在这些长链上荡漾。

零售商和消费者都在这个国家上下急切地感到这个问题。尽管供应链中仍然有食物，但许多人无法获得食物，因为它没有足够快地到达零售商。问题不在于全球生产的粮食数量，而是将粮食提供给需要粮食的人的后勤障碍。

受控环境农业

为了减少粮食短缺的风险，必须立即采取行动以最大程度地减少干扰并加强当地粮食网络。受控环境农业（CEA）是改善当地粮食安全的最有效方法之一。特别是在无法进行露天种植的城市和郊区地区，CEA农场可以将产品种植在靠近消费者的地方。

受控环境农业（CEA）是改善当地粮食安全的最有效方法之一。

CEA听起来很像：一种在可控环境下种植植物的农业形式。CEA不仅允许种植者在以前不可能的地方生产食物，而且还优化了对水，土地，肥料和劳动力等资源的利用。从温室到垂直农场，CEA有多种形式。所采用的三种主要技术是水培法，水培法和航空电子学。

水培法是在没有土壤的情况下种植植物的方法。取而代之的是，植物的根系垂在营养丰富的水中。水培生长的植物比土壤生长的植物生长快25-30％。水培法可在两个使用日光的温室中使用，也可在LED照明下的垂直农场中使用。

从本质上讲，水培法是水培法的一种形式，但是水产养殖产生的废水不是将营养物溶解在水中。水生动物的粪便积聚在水中。然后，将这种富含废水的水送入水培系统，在该系统中，副产物分解为硝酸盐，然后被植物吸收为养分。然后将清洗后的水再循环回水产养殖系统。

气培法与水培法相似，但是它们的根部不是垂在营养液中，而是垂在营养密集的薄雾中。在水培系统中生长的植物显示出比在水培系统中生长的植物明显更快的生长速率。

相比之下，水耕系统将植物的根部浸入营养丰富的水溶液中，该溶液要么保持为狭窄的膜状，要么淹没并排干，使植物的根部间歇性地暴露于空气中，然后再暴露于水中。在这样的系统中，根只能使用溶解在营养液中的氧气，由于其溶解度低，其浓度极低，在室温下约为8mg / L。在大多数CEA设施运行的温度升高的情况下，这种气态缺陷加剧。温度每升高10倍（最高30倍），根部对氧气的呼吸需求就会大约翻倍。植物的新陈代谢随着光合作用的增加而增加，从而进一步增加了农作物的需氧量。

At concentrations of less than 3mg of oxygen per litre of water, root growth is significantly inhibited. In these hypoxic conditions, plant growth is limited by this reliance on anaerobic respiration, which is up to 15 times less efficient than aerobic respiration. As well as slowing growth, anaerobic respiration can result in the creation of unwanted fermentation products: ethanol, alanine and lactate in some plants.

Aeroponics itself is not new. It was originally developed in coordination with NASA in the 1980s with the intention of growing food for astronauts in space. These early design aeroponic systems worked by forcing nutrient rich water through numerous tiny valves embedded in pressurised tubing to create an aerosol. The resultant mist was then deposited on the plant roots.

These pressurised systems, called High Pressure Aeroponics, or HPA, are useful on small scale projects but are difficult to scale into a productive CEA farm. One common problem in these systems is nozzle clogging. As the water moves through the system, it picks up plant debris and the nutrient solution can calcify to form something similar to the limescale in a kettle, both of which can block the small holes within the nozzles.

In an aeroponic system, clogging of the nozzles represents a danger to the plants under cultivation. As the only water available to the plants is in the mist, if these holes are blocked for as little as three‐six hours under lights, the plants can wilt or even die. Because of this, the grower has to check and perhaps change the nozzles often. This flaw in the system has prevented growers accessing the full benefits of aeroponics on a large scale.

New technology for indoor farming

LettUs Grow是总部位于英国布里斯托尔的室内农业技术提供商。该公司为温室和垂直农场设计了一项正在申请专利的室内耕作系统，以解决全球粮食安全和可持续性问题。这些室内农场不需要肥沃的土地来经营，使用零农药，而且全年都可以提供稳定，可预测且具有气候适应能力的粮食供应。

该技术围绕两个核心产品：一种新颖的航空系统和一个集成的农场管理软件Ostara。与目前的室内耕作方法（例如水培法）相比，使用此系统，我们显示了各种农作物的显着增长率。这是通过比传统的田间耕作少用95％的水和肥料以及比水耕系统少30％的水来实现的。

Ostara自动化并控制整个室内农场，同时收集植物数据，监督对作物生长的投入并允许农民追踪从种子到销售的作物，从而提高了运营效率。将这两项创新技术结合在一个隔热的生长室内，以创建一个独立的农场，即LettUs Grow Farm Module。

在与行业标准水培法的并行试验中，我们发现早期农作物的增长率高达150％。这种增加的原因是植物根系获得氧气的途径得到改善。因为根系悬浮在空气中而不是土壤或水中，所以它们可以进入大气中的重要气体，例如氧气。与传统的水耕系统相比，这可以实现更高水平的根气交换。

无压力航空电子系统的优势

LettUs Grow的无压力航空电子系统已被设计为在没有系统复杂性的情况下具有航空电子的所有优点。我们已经完全卸下了喷嘴，因此没有阻塞和破裂的现象。这也使系统擦拭干净且易于操作。

该系统可提高养分施用的精度，因为可以轻松地针对每个生长床微调产生的水雾量，而不是在许多水培系统中更集中地分配水。这意味着可以根据作物来控制灌溉。提供给作物的养分，水和气体的水平可以根据植物的个性化需求进行调整，并根据植物的发育阶段进行调整。

该系统中根的可及性意味着植物不易发霉或其他感染。由于气雾剂仅少量施用于作物根部，因此生根介质保持干燥，并且在此过程中使用紫外线杀菌和适当过滤，可确保将虫害或疾病暴发的机会控制在最低限度。这意味着没有必要将植物暴露于农药中，从而使系统不仅对植物健康，而且对消费者和环境也更健康。越来越多的种植者利用病虫害综合治理（IPM）原理来利用生物防治措施，从而进一步保护了农作物和消费者，而无需使用农药。

传统上，CEA农场最大的间接费用之一是能源成本。对于垂直农场，它最多可贡献总业务成本的40％。通过直接连接可再生能源供应商Octopus Energy for Business提供的敏捷能源关税Vertical Power，Ostara软件平台可用于减轻此需求的财务和环境影响。这是专门为CEA农场设计的唯一能源关税。垂直电源电价实时跟踪能源定价，非常适合智能运营管理以降低成本。通过将灵活的能源价格纳入Ostara，室内农民可以调整植物的生长周期，以适应较低的能源成本，从而节省资金，减少它们对地球的影响，并充分利用与批发能源市场链接的自动化系统。LettUs Grow以“垂直电力”电费为模型，模拟了“典型”垂直农场的节余-成本降低了12％。

CEA农场有可能极大地破坏当前的新鲜农产品供应链，同时在此过程中向种植者传达收益。

CEA农场有可能极大地破坏当前的新鲜农产品供应链，同时在此过程中向种植者传达收益。在英国这样的温带气候下，从1月到12月，全球食品网络用于将季节性产品（例如草莓，西红柿和色拉产品）存放在货架上。

在CEA农场中，天气不会影响农产品，因为它始终是一个宜人的夏日，并且内部生长条件理想。通过将这些农场布置在靠近消费者的地方，可以减少对长距离供应链的依赖，从而缩短食品里程，并增强社区的区域食品安全。

有能力生产稳定，可预测的新鲜食物，有助于减轻农民的“大量悖论”。尽管在许多市场中，对商品的稳定需求是一项资产，但在农业中却可能给种植者带来麻烦。

当良好的生长条件和农产品过剩导致对种植者的需求减少而导致种植者的收入减少时，就会引起大量的悖论。例如，由于生菜市场饱和，生菜价格下降，这种丰收使种植者的收入减少。

结论

LettUs Grow的成立是为了使世界任何地方的任何人都能在消费点附近种植新鲜农产品。

有能力生产稳定，可预测的新鲜食物，有助于减轻农民的“大量悖论”。

我们的使命从未像今天这样紧迫。由于冠状病毒大流行，英国精细的实时食品供应链受到了严格审查。目前，英国仅生产其所消费食物的大约50％，这使其容易受到全球供应链冲击的影响。

CEA耕种不可能在短期内足够快地推出来显着影响当前的冠状病毒危机，但这种流行病已成为人们对我们食品系统弱点的广泛关注的亮点。

这可能是解决更广泛的粮食安全问题（如因土壤流失而引起的问题）时需要警醒的呼声–世界三分之一的土壤由于农业或气候变化的影响而严重退化。

气候变化已经在影响我们的粮食系统。极端天气事件，例如2018年的热浪或2019年的洪灾，摧毁了农民种植农作物的能力，它们变得越来越普遍。

大都会办公室的计算机模型表明，由于人为气候变化，现在这些天气事件的可能性是30倍。在一个大气中CO ₂含量未超过工业化前水平的世界中，这些事件每200年发生一次。现在预计它们将是八分之一。

在受天气变化影响的地区，CEA农场可能被证明是基础设施的重要组成部分，可确保为消费者提供稳定的食品供应并保护世界各地农民的生计。

印度Langley，LettUs Grow，英国布里斯托尔

电子邮件india.langley@lettusgrow.com

网页lettusgrow.com