While admiring the view from the header this year, remember to keep an eye out for weeds and volunteers as they could already be giving you issues for the 2017 season.
Not only do they provide the perfect environment for pests and diseases, they are also using soil resources that could be available for the next crop.
Disease
This year provided the perfect environmental conditions for diseases and pests, therefore carry over of these issues to the 2017 season need to be mitigated.
Weeds and volunteer plants enable diseases and pests like rust, aphids, viruses, mites and root diseases to be carried through to the following season.
Rust especially requires living plant material to persist over the summer.
The green bridge is any vegetation that provides suitable habitat for pests and diseases to live during the summer months.
Weeds and/or volunteers make up the green bridge, and can be plants left over during the growing season or those that have grown after harvest.
Being mindful that any summer rain can cause a flourish of summer weeds will be critical in reducing the green bridge and ease disease pressures into 2017.
Nutrients
Nutrients, especially nitrogen (N) are a significant input into the farming system, and therefore conservation of existing N can provide a cost effective long-term solution.
In a four year project (2009-2012) conducted by BCG, treatments that included summer weed management had higher levels of N available for crop growth.
Summer weeds reduce levels of available N by both removing N through growth and subsequent seed production, and reducing the ability for soil to minerialise N.
The study also showed that in years of high growing season rainfall, it is the retained nitrogen which assists in the production of higher yielding crops.
Moisture
The principle also applies in dry seasons, where it is actually the retained soil moisture that provides the ability to produce higher yielding crops.
The saying goes “that moisture in the profile is money in the bank” which has been notable in the couple of recent dry seasons.
In each of the four years the trial was conducted, each had a higher return on investment when summer weed control was undertaken.
This year has been an especially wet season for many areas, with the possibility that soil moisture can be transferred to the 2017 growing season.
While next year’s rainfall is unknown, any soil moisture at the start of the season will not be unhelpful.
Ensuring that summer weeds do not erode this resource and any summer rainfall can be maintained will help start 2017 on the front foot.
The article was published in the Stock and Land on November 30, 2016.
