March 2010 edition
Sowing in the North East
Nathan Shannon, Dairy Extension, Department of Primary Industries, Wodonga
Over the past four years a group of farmers in the Kiewa Valley have meet on a regular basis as part of the 3030 Partner Farm, Development Group. With volatile imported feed prices affecting the bottom line of every business the key focus of the group has been on growing forage and in particular trying to fill ‘feed gaps’ with cost effective techniques without dramatically increasing the risk profile of the farm.
The next few months can be most critical times of the year for autumn calving herds, when high quality grazing feed is required for fresh cows. With the varying autumn breaks that the region has experienced in the last decade, the group has discussed forage options that endeavor to provide this highly valuable forage into the herds’ diets.
The obvious answer is simply to sow earlier. However, firstly we cannot sow too early (January) when soil temperatures are generally too high (above 32 degrees), to allow seeds to germinate. Secondly, by sowing early we increase the risk of failure, that is, when seeds strike but then die before there is any follow up rain to sustain growth. When this occurs the cost of the initial seed, and sowing (contractor or own time and diesel) has been lost and also crucial growing time (by the time an assessment of failure has been made it is generally well into April), not to mention the need to re-sow, often when calving is in full swing.
To reduce the risk of failure a number of options can be considered:
- Cultivate paddocks in late spring/early summer to capture any storm rains and to control summer weeds (the traditional summer fallow).
- Provide a fine firm seedbed. If a paddock has not been fallowed, it is still possible to improve the seedbed with a power harrow or light disking. This procedure provides a loose soil around the newly sown seed which enables the soil to hold more moisture from each rain event; as a result the new plants have greater access to moisture. Note, lighter sandy soils this may not be required
- Sow species capable of tolerating dry periods. Large seeded species such as winter or forage cereals fit this category, however, be sure to choose a cultivar that will not ‘run to head’ before the winter. Annual ryegrass varieties also generally have a larger seed size than biannual and perennials, hence these can be sown slightly earlier with reduced risk of failure.
- Sow deeper (it is not the dryness that causes failure; it is the moisture that causes germination of the seed followed by the dry spell). By sowing deeper the germination after a small rain event may be prevented. In previous years it was shown that ryegrass sown three days after 15 milliliters (mm) of rain in March germinated but died quickly as there was no follow up rain to keep the plant going. Paddocks sown on the same farm the day after the rain survived but were severely moisture stressed early. Plants sown six days after the rain event did not strike until the next rain event.
The 3030 group are very aware that sowing times are not dictated by the calendar, but rather by reading the season; however they have come up with the following general guides for sowing times for different varieties on dryland farms in the North East region:
- Forage oats, sow into a fallowed paddock from early/mid February– Choose a long season, late maturing variety. Sow 25-50 mm deep, the later into the season the shallower the sowing depth. These provide first grazed feed into annual system (six to eight weeks after the germinating rain), high quality grazing fodder at times of feed shortage, and high silage yield of good quality. Also, being early finishing (early October), these paddocks provide options for a summer cropping program.
- Forage oat/ryegrass mix, early March sown into a prepared (fallowed or power harrowed) ground – ‘shifts’ some spring surplus into autumn grazing. Ideally requires two sowing passes, oats at 50 mm, ryegrass at 15 mm. Oats will provide the bulk of the forage at the first grazing with ryegrass coming on later in the season. The ryegrass is a ‘risk management’ tool for a wet season (cereals may die if they are waterlogged). The ryegrass also improved the crude protein percentage in the silage.
- Italian/hybrid/biannual ryegrass and brassica mix (25 kg to one kg). Begin sowing from mid March – sown at a depth of 15-25 mm the brassicas will provide fast early growth while the ryegrass is establishing. The best results have been obtained with some seed bed preparation such as a power harrow following January/February rains. Brassicas are reasonably tolerant of a dry period after germination and have the ability to grow high quality fodder if moisture is available. By adding the brassica to the ryegrass sowing costs have increased by $10-20 per hectare (Ha), however the first grazing can be two to three weeks earlier and have an increased yield of one to two tones of dry matter (DM)/Ha. After the first two grazings the ryegrass will take over and by spring there will be very few brassica plants left in the sward allowing for typical ryegrass management and ensiling through spring.
- Annual ryegrass, sow from mid/late March – Fast establishment, good winter and spring growth, however in recent years have failed to make use of late spring rains given the start stop nature of the seasons. These are best used for ‘short season’ paddocks that dry off early i.e. sandy soils or north/western facing slopes.
- Italian/hybrid/biannual ryegrass, late March sown – slightly slower establishment than true annual varieties however provide good winter and spring growth, high quality high yielding silage. Makes great use of late spring/early summer rainfall, although the sowing costs will be greater than an annual ($2/kg verses $5/kg x 25kg/Ha = extra $75/ha) the value of the extra feed grown through late spring has the potential to well outweigh this (i.e. extra 2-3tDM at $250/t = $500-750/ha).
- Perennial pasture, sow from April onwards when the risk of a false break is significantly less – high yielding, great management flexibility, high quality year round, low costing, low risk. Research from the 3030 project across all areas of the state has conclusively sown that ‘If we you get Perennial Pastures to persist, we should grow them’; this takes into account the risks of growing both annual crops and perennial pastures and also the financial results of each system.
For more information on the 3030 project and its results, sowing times, paddock preparation, and choosing a forage for your farm system please give Nathan Shannon a call on (02) 60 437 961.
