The use of pulses within the UK arable rotation has an important role to play in improving the environmental sustainability of agriculture by decreasing use of synthetic N fertiliser, lengthening rotations and increasing biodiversity and variability in the farmed landscape. Our bi-cropping trial is also timely, coming as it does at a time when a payment is newly available under the new Sustainable Farming Incentive (SFI) for bi-cropping (£55/ha). This payment, alongside robust research which will hopefully demonstrate the benefits of the technique, will help encourage farmers to consider bi-cropping as part of their normal rotation.
Objectives:
- To assess the feasibility of growing peas on a heavy clay soil, using oats as a bi-crop for support.
- To assess the impact of growing a pulse bi-crop (vs a cereal monocrop) for greenhouse gas emissions.
- To assess the impact of growing a pulse bi-crop (vs a cereal monocrop) on soil nitrogen and a future crop of wheat.
Experimental layout:
The experiment will be a tram line experiment, drilled spring 2024 with 4 treatments replicated 4 times. The treatments are spring peas, spring oats, spring peas and oats bi-cropped and spring beans.
The bi-cropped treatment will be drilled at standard rate for peas, and at 50 plants per square meter for oats. The other crops will be drilled at standard rate. Their will be normal farm practices used for all fertiliser and chemistry. No fertiliser will be used on the bi-cropped treatment.
In September 2024 we will harvest using a separator for the bi-crop, and use a standard harvest method for other crops.
In Autumn 2024, a crop of winter wheat will be drilled across all plots, to assess the N impacts of the treatments on the next crop.
Assessments:
- SMN probes, probes to be put in across two of the replicates, giving 8 probes in total.
- Greenhouse gas fluxes in the field (Gasmet DX4040 portable FT-IR gas analyser and li-cor survey chamber) One measurement per plot, done monthly, with additional sampling when nitrogen is applied. In 2nd year WW crop will aim to take additional samples directly after N application.
- Soil texture
- Soil structure (VESS)
- SMN before and after legumes in all plots
- Soil nutrient status (P,K) – sent to labs same time as SMN,
- SOM – use LOI in house test.
- Soil carbon – calculated from SOM
- Establishment – plant counts at 100% emergence
- SPAD meter assessment – monthly when established. 30 readings per plot averaged.
- Harvest and yield – taken from combine.
- Grain analysis – protein content
- Weather data
- Satellite imagery is available, but need to check resolution for plot scale analysis.
