William Curran
Professor of Weed Science
A survey of no-till farms using cover crops indicate 30% of growers plant their cash crop into a green cover crop.
Last spring and early summer, we conducted a short cover crop management survey among a small number of no-till farmers in PA. We had 27 farmers who are very committed to no-tillage and cover crops take the survey. We were particularly interested in what these farmers thought about “planting green” or not killing a cover crop until after cash crop planting. There are several reasons for interest in this tactic including improving soil quality, moisture management, slug management, and perhaps more successful establishment of the cash crop and improved weed control. This survey just touched on the surface of the issue of planting green but will hopefully help us better design field trials that investigate the potential benefits and disadvantages of allowing cover crops to grow longer in the spring. The following is a summary of what we learned in this survey.
Most of the farmers in our survey group grow corn, soybean, small grains, and perennial forages. Over 90% of the group used cover crops in the previous 3 years and about one-third had used cover crops for more than 10 years. The most common cover crop was cereal rye (92%), followed by other cereals (oats, triticale, etc.) and forage radish (64 to 68%), crimson clover (52%), annual ryegrass (48%), other legumes such as hairy vetch or winter peas (40%), and 20% utilized red clover. Almost half of the respondents have used cover crop mixtures. We asked them about their preferred timeline to kill the cover crop relative to planting the cash crop under “normal” weather conditions. Almost 40% currently terminate their cover crop more than 2 weeks before planting, about 25% one to two weeks ahead, 8% less than one week ahead, and about 30% at or after planting (‘planting green’). Although planting green is used by one-third of these farmers, it appears that many still like to make sure the cover crop is dead at planting time. When asked why they kill their cover crops when they do, almost 50% consider soil moisture conservation as a very important driver and 35% are very concerned about too much cover crop residue, which might compromise seed placement. Several of these farmers have commented that ensuring cover crops are not seeded too dense can help with cash crop planting the following spring. Slugs were also an important consideration for timing of control (35%) as was waiting a bit longer for N fixation from legumes. About 25% of the respondents terminated at a time to ensure effective cover crop control. Interestingly, few farmers terminated based on insect pests, concerns for N immobilization, allelopathy, or for weed control. We think this survey will help us formulate some research plans and we thank these farmers for participating.
Source : psu.edu