Crop Rotation Strategies for the Control of Field Bindweed (Convolvulus arvensis)

Research Importance 

 

Field bindweed (Convolvulus arvensis L.) is a perennial rhizomatous forb. Other common names for Field bindweed include creeping jenny, European bindweed, and perennial morning glory. Field bindweed is a priority 2B noxious weed in Montana, meaning it is an abundant and widespread weed. It has been reported in every county in Montana.

Field bindweed can quickly establish in disturbed areas and is most commonly found in agricultural fields, pastures, hayfields, gardens, lawns, and roadsides. This weed is particularly hard to control due to its ability to spread via both seeds and roots. Reproductive buds found on the roots and underground stems can produce new plants when they are cut and may be spread by tillage equipment. Seeds are dispersed locally as well as more distantly with harvesting equipment and as a contaminant in crop seed. Field bindweed seeds are long-lived (e.g., 20 or more years).

The twining growth habit of this weed is capable of forming dense, tangled mats that interfere with harvesting. Dense field bindweed infestations can reduce crop yields by 50 to 60 percent. While field bindweed is most problematic in agricultural fields, particularly organic systems, it is a weed in turfgrass and a concern in perennial pastures. Alkaloids found in field bindweed are mildly toxic to certain types of livestock (e.g., pigs and horses) and can cause digestive disturbances.

Research Summary

In the fall of 2017, ten cropping systems treatments that combine tillage and competitive crops to manage field bindweed in irrigated organic grains were started at the MSU-Western Ag. Research Center. The treatments are designed with the primary goal of managing existing field bindweed populations over two years and spring wheat will be planted in all treatments in 2020. 

Results

Overall, the reference treatment (spring wheat-pea green manure rotation with standard tillage) resulted in the greatest increases in field bindweed populations.

Spring 17-19: The reference treatment had the highest field bindweed population growth rate. The growth rate of 2.06 translates into a nearly 8-fold increase in the bindweed population over two years. Adding more intensive tillage to the reference treatment did not significantly reduce the bindweed growth rate, but adding more competitive, fall-planted crops did. Most treatments reduced bindweed growth rates relative to the reference treatment and had stable bindweed populations (i.e. growth rate similar to zero). The weed population growth rates were similar among most of these treatments (indicated by a shared letter in the table below), except for the reference where we added more competitive, fall-planted crops with resulted in lower growth rates than the ref-tilled and the reduce tillage, double cover crop. The intensive tillage 2 (rototilled + plowed) and conventional alfalfa were the only treatments where bindweed populations were declining. At this time, the conventional alfalfa had lower bindweed growth rates than organic alfalfa, but this was not the case in the fall (see below).

*Population growth rate calculation: We compared change in field bindweed counts over years at similar time periods using natural log of (final count/initial count). Using this metric, bindweed populations that are staying the same size (initial count=final count) will have a growth rate of zero; growing populations will have a growth rate >1; and declining populations will have a growth rate <1. 

August 2017-2019: The growth rates measured at the end of the 2019 growing season produced different results compared to those rates measured in the spring. The reference treatment had the highest field bindweed population growth rate. The growth rate of 2.94 translates into a nearly 19-fold increase in the bindweed population over two years. Adding tillage or competitive crops to the reference did not significantly reduce the bindweed population growth. The integrated livestock treatment was also similar to the reference, suggesting that bindweed increased in number while the sweet clover was being grazed (and not tilled) during the summer of 2019. The only treatments that reduced bindweed population growth relative to the reference were the warm season cover crop with frequent spring tillage, both intensive tilled fallow treatments, and both alfalfa treatments. By August, there was not advantage of decertifying and using herbicides to control the bindweed in the conventional alfalfa compare to the organic alfalfa. The most intensive tillage treatment (ITF2) was the only treatment where bindweed populations were declining. However, the soils in the intensive tilled fallow treatments were beginning to show signs of damage (e.g. loss of structure and increased risk of erosion, see below).

*Population growth rate calculation: We compared change in field bindweed counts over years at similar time periods using natural log of (final count/initial count). Using this metric, bindweed populations that are staying the same size (initial count=final count) will have a growth rate of zero; growing populations will have a growth rate >1; and declining populations will have a growth rate <1.

Publications and Other Resources

Field bindweed publication by Montana State University Extension 

Field bindweed ID and control information

Montana Field bindweed guide

Montana Weed Control Association