Catch Crop Project is underway

We are excited to get the Catch Crop NZ project underway! Thanks to the support of our co-funders, our team of scientists and our farming partners, we can undertake what is to be valuable research into the benefits of Catch Crops in New Zealand.

Over the next two years, our team of rural professionals and scientists will be out on the farms evaluating a range of crop species and establishment techniques that have the ability to reduce sediment and surface flow losses following winter grazing of forage crops. The project will test both the environmental benefits and the economic benefits.

The On-Farm Research farm at Poukawa will be the focus of trial work with other sites in Hawke's Bay and Manawatu providing support data.

The following is the Methodology for data capture at the site

Methodology

Background info:

1. The trial will be located at the Poukawa Research Station, 1391 State Highway 2, Hastings.

2. Trial period: Autumn 2019 – Spring/summer 2020

3. Soil type: Roseberry silt loam, Typic Orthic Melanic, moderately deep – 60-100 cm, well drained, topsoil 10-20% clay (S-map)

4. Trial name: Y1 Poukawa SFF Trial 2019

5. Soils samples will be taken from the general trial area for background soil fertility assessments.

6. Prior to the commencement of the trial, the paddock/trial site will consist of forage kale and be grazed by livestock during autumn or winter.

Trial layout and treatments:

1. Randomised block design; 3 treatments, 3 replicates = 9 plots total (Figure 1).

2. Treatments will consist of:

3. Main plots will be 10 m long by 3 m wide (TBC).

4. After grazing by livestock, individual plots will be isolated and sediment runoff monitoring equipment will be installed at the downhill end of each plot.

5. At the earliest convenience after the sediment traps have been installed, catch crops will be sown by broadcasting and raking seed into the soil ( to simulate seed soil integration that might occur with stock treading the seed into the soil) at standard sowing rates (targeting a minimum population of 300 plants/m2 for cereals and ).

Measurements:

1. Sediment and nutrient runoff losses will be measured using an automatic collection system to measure the runoff volumes and to take a proportional sample of nutrient and sediment loads. Nutrients of interest include dissolved reactive phosphorus (DRP), total phosphorus, mineral nitrogen as ammonium and nitrate, dissolved organic carbon (DOC) and dissolved organic nitrogen (DOC). Samples will be collected after each large runoff event (>25 mm) or monthly as required. Installations will be made by PFR and monitored by on-farm staff located at Poukawa.

2. At 3–5 weeks after sowing, plant numbers within a subplot (1 m by 1 m) will be counted to determine emergence percentage/plant population.

3. Canopy development rates will be monitored until canopy closure using green-seeker (NDVI) measurements conducted every 2-4 weeks after emergence.

4. Biomass will be measured at green chop silage maturity (50% ear emergence), using a 0.5 m2 quadrat (two quadrats bulked per plot). Cuts will be taken from each plot to ground level and total fresh matter weighed. Subsamples will then be oven-dried at 60°C for 48 hours and reweighed to determine dry matter percentage and yield. Samples will then be analysed for total N content to determine crop N uptake (above ground) using a LECO CNS analyser. The total P content of the plant biomass will also be determined (samples analysed at ARL Laboratories)

5. Further crop subsamples will be taken, freeze-dried, finely ground and analysed for quality components (e.g. metabolisable energy) at green-chop silage maturity.

6. Climate and soil data [i.e. solar radiation, air temperature, rainfall), soil temperature (at 5 cm depth) and soil moisture (at 5cm)] will be obtained using a data logging system connected to a wireless modem for real-time data acquisition.

7. A flow meter and a 12 V pump will be connected to the outflow of each sediment trap. A data logger will be used to record the runoff volumes from each plot (Figs 1 & 2).

Figure 1. A schematic of the trial plan for the 2019 Poukawa catch crop trial. Sediment traps placed at the lower end of each plot will capture the runoff water. This water will be pumped through a flow meter, to record volumes and provide a measurement of the runoff (mm). A proportional sampler at the outflow will capture a water sample. This sample will be analysed at the laboratory to provide a measure of the concentration (mg/L) and total runoff losses (kg/ha) of the target nutrients and also the sediment.