By Tim Ellis, Bentley Hall Farm, Staffordshire
As we start to turn our attention to the growing season in hand, we are planning a number of robust farm trials in both Yorkshire and Staffordshire using Plasma Activated Water (PAW) as a potential nitrogen fertiliser replacement. These trials are part of our ADOPT innovation project funded by DEFRA.
Based on US trials, our plan for using PAW in Staffordshire on winter wheat includes: applying Firewater in furrow at drilling (which we missed for autumn crops this year but will try next season), an early spring soil applied nitrogen application (UAN, Ammonium sulphate or similar, prilled or liquid), and two to three foliar Firewater sprays depending on the crop and season.
Our winter wheat was drilled in late September and early October in near perfect conditions with a seed drench comprising of Aiva Phosphorus (with nitrogen, phosphorus, Sulphur, magnesium and zinc), Nurture N (humic and fulvic acids), bio plus T (beneficial microbes) and wood vinegar.
A variety of in-organic and organic nitrogen sources are considered the optimum method of encouraging healthy balanced growth and with the plants coming out of the winter with a small leaf area, an early soil applied application of UAN or ammonium sulphate makes sense. Applying nitrogen to the soil early should benefit plants: ammonium supports root growth, while nitrate aids foliage growth. At this stage, there isn’t enough leaf area for effective foliar spraying of Firewater.
The second application will use Firewater in a foliar spray as a nitrogen fertiliser replacement. US studies have shown that Plasma Activated Water can support natural nutrient cycling by encouraging existing soil biology, helping plants utilise nutrients already present in the soil.
However, since we are farming on a sandy loam soil (75% sand), I am concerned about both the current nutrient levels in the soil and whether the soil biology is in sufficient quantities to make these nutrients plant available, especially after years of heavy artificial inputs and tillage.
The beauty of Firewater’s PAW is that it is inert, so we could combine / mix with practically anything (we will bucket test first). Our thinking is to combine this application with a multi micronutrient product, a humic/fulvic acid and maybe even an amino acid addition to provide the plant with balanced nutrition for optimum growth. We will also carry out tissue or sap testing before applications to remedy any nutrient deficiencies.
This approach will also provide the plant with the nutrients required for enzyme production to convert the nitrate into firstly ammonium (molybdenum, Sulphur and iron), ammonium into amino acids (manganese and magnesium) and finally into proteins (phosphorous, Sulphur, manganese, magnesium, boron, potassium and zinc). The idea behind applying Firewater with a micronutrient product is to help the plant do the heavy lifting with the photosynthetic energy needed to convert nitrate along the metabolic pathway into protein.
The third and fourth applications will be based on the same approach and combination of products. Tissue or sap testing will be carried out so we can tailor what nutrients we apply to address any deficiencies to maintain a healthy balanced plant.
The use of an amino acid product with the application will help meet the need of both organic and in-organic forms of nitrogen the plant prefers and help prime the nitrogen metabolic pathways once the nitrate is converted into amino acids.
This may seem like a belt and braces approach but will translate into less passes with the sprayer. Our current farm standard is to apply a separate nitrogen application and then a micronutrients/biology application, this combines the two applications into just one pass.
We will of course trial Firewater on its own, just in case none of this is necessary!
Timing of the foliar applications is also important. Ideally, we will apply either early in the morning or late in the evening – with humidity above 70% and temperature under 20C to ensure the plant is receptive and the stomata are open.
Firewater has been used successfully as a carrier for fungicides in the US, so this will also help reduce passes with the sprayer, but trials suggest that even though there is a yield bump from applying a fungicide with Firewater, there is an even bigger bump by just applying Firewater on its own at the fungicide timing – time will tell.
As discussed in an earlier blog, a healthy, nutritionally balanced plant can fend for itself against insects and pathogens. The ultimate aim is to not only reduce our reliance on nitrogen fertiliser but also remove our fungicide use.
