Measuring pastures’ condition (South Island)

How to measure pasture condition (South Island)

Due to the challenging season (summer 2019/2020), there will be paddocks on farms that require under-sowing or ‘stitching up’ this autumn. To identify and prioritise which ones, we recommend walking all your paddocks to be able to properly assess plant density, insect damage, weed presence and to allow implementation of an under-sowing strategy.

Use this tool to help make on-farm decisions

Run out paddocks that score between 1-3 will be those you target for under-sowing.

5: Paddock covered in dense swards of desired grasses and clovers

No action required. Would be happy if the whole farm was in this state.

4: Patches of low-level damage, some weeds, less vigorous grasses

Check fertility. Apply autumn N to encourage tillering. Paddock probably OK for the coming season (2020/2021).

3: Large sections of low-level damage, weeds, less vigorous grasses

Apply autumn N. Under-sow in the autumn with perennial ryegrass (longer term solution) containing appropriate endophyte.

2: Severe damage in parts, many weeds, patches of bare ground

Either:

• Sow in perennial ryegrass in autumn, or:
• Under-sow with Italian ryegrass in autumn and plan to renew in following 12-18 months.

1: Severe damage across entire paddock

Sow into an annual ryegrass and summer crop in spring. Plan to sow in perennial pasture in the following autumn.

Once you’ve Pasture Condition Scored the farm, you’ll be able to prioritise which paddocks require under-sowing.

Choosing the pasture you need next will depend on how long you need it to last.

Here are our recommendations:

Winter Star II tetraploid annual ryegrass

For a 6-9 month option for paddocks destined for cropping or renewal in spring. Condition Score 1 paddocks should be sprayed out and sown into a full rate of Winter Star II.

Lush tetraploid Italian ryegrass

For an 18-24 month option that can provide a high quality short term fix before you plan to fully renovate the pasture. 

Platform perennial ryegrass

For 24+ months; great for productive dairy and sheep and beef farms; especially tiller dense; great ability to fill in drill rows fast.

Excess perennial ryegrass

For 24+ months; great for productive dairy and sheep and beef farms; great option for lighter soil types.

Because of the recent weather, soil temperatures are still quite high which means perennials are still a valid option for under-sowing. As the days shorten and soil temperatures drop below 12 degrees, we should switch to Italian ryegrasses (Lush AR37) as they are much faster to establish and have better cool season activity. 

It is important to highlight to your clients “the earlier the better”. Every week they hold off under-sowing is costing them 100’s of kgs of DM! Further, the longer the delay the greater the risk of invasive grasses and weeds getting established thus reducing the potential for a positive outcome from under-sowing.

Tips & tricks

Endophyte

Using a novel endophyte is important when under sowing run out pastures, particularly in pasture with an existing pest issue such as argentine stem weevil and black beetle. 

Seed treatment

All seed that is under-sown should be treated with Superstrike® to protect against pasture pests. This is a cheap insurance, and a small cost when considering the cost of re-drilling the paddock 6-8 weeks later.

Note: Pastures under-sown with Superstrike seed have a grazing withholding period of 21 days. 

Under-sowing rates

Run out pasture scoring a 2-3 with the following rates:

• 6-9 months = Winter Star II
  18+ kg/ha (full rate 28-30 kg/ha)

• 12-24 months = Lush AR37
  15+ kg/ha (full rate 28-30 kg/ha)

• 24+ Months = Platform AR37 or Excess AR37
  12+ kg/ha (full rate 18-21 kg/ha)