Lettuce - Primaflor, Spain
Inputs
Fertigation
The farm uses a fertigation system, which is the application of soluble fertilisers through an irrigation system. This provides precise nutrient applications to the plant, and controls the pH levels of the irrigation solution. The business has a defined plan for nutrient application which is implemented on the basis of planting dates, soil type and crop type. This method of scheduling reduces the effects on the plants of over- or under-fertilising and results in improved plant growth. Fertigation allows the plant to absorb up to 90% of the applied nutrients, whereas granular fertiliser applications typically result in absorption rates of 10-40%. Another drawback of granular fertiliser applications is that they rely on rain or topical applications of irrigation (which is wasteful due to high evaporation losses) to dissolve the fertiliser granules. With this precise application method and defined planning system, the overall amount of fertilisers applied is reduced verses granular applications.
As the fertigation system is targeted at the plants’ root zone the risk of runoff or leaching is greatly reduced, which is also aided by the small amounts of fertiliser applied in each drip cycle.
Use of fertigation ensures accurate and precise nutrient application, ensuring minimal waste and maximising plant growth.
Irrigation
Water is a precious resource in this growing region and also contributes around 20% to the cost of production. To ensure that irrigation is undertaken in the most efficient approach the farm has integral soil moisture meters within the growing crop to monitor soil moisture levels. These have sensors set at four zones within the soil structure at depths of 10, 20, 30 and 50cm. These monitor moisture levels every five minutes and the data is sent via Wi-Fi to a nearby computer system. The computer software charts the moisture levels and also records the amount of water applied via the irrigation system and gathers data from the weather station. All these figures are then assessed by the farms technician who can adjust irrigation amounts from the pre-determined target levels. Any rise in moisture levels recorded at the sensor placed at 50cm deep shows that the crop has been over irrigated and the technician will reduce the subsequent applications of water to address this. At 50cm the water has moved out of the plant’s root zone and is therefore unavailable for its use.
Automatic water monitoring ensures the optimal irrigation. Unnecessary water use is avoided and plant growth maximised.
Weather station, irrigation and pest control
The on-farm weather station is a monitoring device that takes accurate, real-time weather measurements and transmits them to the farm’s computer. It measures wind speed and direction, humidity, precipitation, temperature, barometric pressure, dew point and provides data to calculate soil evaporation rates, which is used within the irrigation models. The farm is also able to use disease/pest prediction models which can direct the use of plant protection products in a timely and cost-effective manner.
The use of ongoing weather monitoring helps predict weather events and disease incidence, enabling appropriate, low impact, preventative actions to be taken.
The weather station also predicts conditions which are likely to increase the risk of disease/pest incidence. With the use of pheromone and sticky traps to capture pest species, a targeted and accurate use of plant protection products can be applied. The other benefit of the pheromone and sticky traps is that if pest threshold levels are exceeded then the farm’s technician can approve the use of specific plant protection products to deal with this in a timely manner before elevated levels are reached.
Biological repellents (garlic extract and neem oil) are used to control certain target pest species. With the use of these two natural products the requirement for manmade chemicals can be reduced, minimising negative impact on the environment.
Low-impact pesticides, such as biological repellents and sticky traps, are used on the farm, avoiding the negative environmental impacts associated with manmade chemicals.