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6. Trial potato growing with refined pig manure fractions

RL3: Tools, techniques & systems for higher-precision fertilization

Responsible partners: ZLTO, Wageningen University, Ghent University

Country: Reusel (Postelsedijk 15), THE NETHERLANDS, Ghent BELGIUM

TRL and Scale of set up:

This demo is considered to be at TRL 5-6 and has been set up at field plots with a large potato grower at farmland. This trial involves using refined pig manure fractions (liquid fraction after anaerobic digestion and scrubbing salt) of one pig farmer with a pig manure processing plant to grow potatoes without the use of chemical fertilizers at one potato farm.

Research line and priority: This demo solution is linked to Nutri2Cycle research lines 3 and 4 (RL-3: Tools, techniques & systems for higher-precision fertilization, RL-4: Biobased fertilisers (N, P) and soil enhancers (OC) from agro-residues) and is under two shortlist priority solutions i.e. sub-research line 21 – Field assessment of precision arable farming using bio-based fertilizers in potato growing (LL73) and sub-research line 7 – Pig manure processing and replacing mineral fertilizers (LL43).

Description of the demo:

This demo investigates the effect of using bio-based fertiliser products in combination with precision agriculture. Different bio-based fertilisers are tested next to mineral fertilisers considering the safe and practical use of these fertilisers for potato growing. The effect on N use efficiency, potato yield and quality, and costs versus revenues are investigated. This demonstration trial is a collaboration between a pig farmer, a company specialised in processing pig manure, and a potato grower, all with the aim to contribute to close the nitrogen loop. The manure of the pig farmer is processed into the following bio-based fertiliser products: liquid and solid fraction of the digestate, scrubbing salt and K-concentrate. The demo set-up is divided into three parts: (i) an incubation experiment to analyse the mineralisation rate of the bio-based fertiliser products, (ii) a pot-experiment to measure the nitrogen fertilizer replacement value, and (iii) a field-trial to test bio-based fertiliser products with different levels of refinement.

(i) The mineralisation rate of three bio-based fertiliser products (liquid fraction of the digestate, scrubbing salt, and K-concentrate) is tested under controlled conditions at the laboratory. To analyse release and mineralisation rate, N – incubation tests are performed over a span of 120 days. For this, four replicates of each product are tested against mineral fertilizer (CAN) at every 20 days. The initial dosage of 170kg N/ha is applied at a WFPS of 50%.

(ii) In a pot-experiment under semi-controlled conditions in an open tunnel, the fertiliser replacement value is derived. This value indicates how well a bio-based fertiliser product is able to replace mineral fertiliser. All three products are tested against mineral fertiliser (CAN and KCl). To draw a yield curve, pots with 0, 20, 40, 70 and 100% of the advised amount of N or K fertiliser are prepared, which corresponds respectively to  0, 62, 124, 217, 310 kg N/ha and 0, 53, 106, 186, 265 kg K2O/ha. The performance of the bio-based fertiliser products is tested with 40% of the advised amount of N fertiliser (in the case of the liquid fraction of the digestate and scrubbing salt) or K fertiliser (in the case of K-concentrate) to get a clear distinction between the different products.

(iii) In the field, six treatments and three repetitions are set-up. The treatments are randomized within the field and received the following products: (i) no mineral and no organic fertiliser (0-treatment), (ii) liquid fraction (based on the recommended amount of N), (iii) liquid fraction and manure, (iv) scrubbing salt, (v) scrubbing salt and manure, and (vi) mineral fertiliser and manure. Except the 0-treatments, all fields receive 100% of the advised amount of N fertiliser (310 kg N/ha). The fields are monitored during the growing season, and soil -and leaf samples are tested for N content. The under-water yield per plot is assessed and therefore, the effect of using different refinement levels of pig manure could be assessed. In the end, the remaining amount of N in the soil is measured per plot to analyze the N leaching. 

How it addresses the Nutri2Cycle goals:

Processing pig manure leads to nutrient and carbon recovery. This field-trial contributes to the Nutri2Cycle goal by replacing mineral N fertiliser for bio-based fertiliser products, which stimulates closing the N loop. Besides, this field-trial also stimulates the N use efficiency by using precision fertilisation techniques.

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🔔 Notice – Document Updates for JARVIS Open Call 1
Please note that updates have been made to the official Open Call documents (Annex1, Annex 1.1, Annex 2).
Please make sure to download the latest versions available on the Open Call 1 webpage before submitting your proposal and check the changelogs that are added on page 2 of each updated document that indicate the changes since the initial version.
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