Green Manure Crops In Sugar Beets
The Amalgamated Sugar Company LLC has about 1,100 growers raising 185,000 acres of sugar beets in Idaho, Oregon and Washington. There are about 100,000 acres that are infected with cyst nematode. Dichloropropene and carbamate are fumigants currently being used to control this pest. Green manure crops, specifically oil radish and mustard, have proven to be effective in controlling cyst nematode. The purpose of this project is to implement the use of a biological control versus chemical on 700 acres of sugar beets and encourage other growers to adopt this method.
When growers can see that biological control is as effective and economical as chemical control, they will begin using these types of control methods. Our goal is to increase the use of biological controls each year to the point that 80% of the acreage or 80,000 acres infected with nematode will be treated biologically.
Project goals and objectives
1. Familiarize all of the 1,100 growers in our company with the green manure cropping practice
2. Show the growers that there are many agronomic benefits to green manure crops.
• Of the 900 growers currently using 107 lbs/acre dichloropropene or 33 lbs/acre carbamate to control sugar beet cyst nematode, 10 growers will eliminate their use of these chemicals by growing a green manure crop in 2005.
• In 2006, the number of growers will increase from 10 growers to 30 growers not using chemicals or from 700 acres to 1,500 acres.
1. We were able to meet all the objectives of our first goal. Thanks to the help of the company fieldmen we were able to get more than half of the growers in each area out into the fields. We were able to reach more of the growers in our winter meetings. There were also presentations given at the annual University Of Idaho Agronomic School. The northwest fertilizer organization was given a presentation at their annual meeting in Jackpot Nevada. There were two industry publications that had articles on the work we are doing. When the growers signed their contracts in the spring of 2006 the fieldmen discussed the program again with them. We were able to reach all of our growers and inform them of the work being done.
2. The results from our second goal were not as successful as I would have liked them to be. It appears that when you are trying to amend soils organically it is going to take more than one year to accomplish. We were able to have a major economic effect on cyst nematode control. We reduced the population by 90%. Tonnage was affected but only by a small margin. There was a one to two ton increase, which may not be enough to change the current trend. We found no differences in sugar content, disease control, or water infiltration rates. There were more beets per hundred feet of row in the radish plots over the check plots which helps explain the increase in tonnage. Our work with nitrates looks very promising. We are indeed able to hold the nitrates at the surface for better utilization in the spring. This will help keep nitrates from going into ground water and there will be less applied in the spring.
The erosion study showed that we could plant through the debris on the surface and the roots that were still in the soil. The roots did not cause any disease problems with the small sugar beet root. This plot was planted in late August. We did not get enough plant growth to cover the ground adequately. If you are going to use mustard for erosion control you need to be able to shred it twice. This would require planting the mustard in late July so that there would be enough growing time for it to be shredded and then have enough time to grow back to be shredded again. The second or last time it is shredded I would leave about 4 inches of stem.