Gordon Johnson, Extension Vegetable & Fruit Specialist; gcjohn@udel.edu
No-Till Processing Vegetables
There is increased interest in no-till production of processing vegetables. No-till production is possible for most of our common processing vegetables. However, success will depend upon a number of factors. For spring planted crops, soil temperature and emergence will be the dominant issue. For summer plantings, especially into small grain stubble, soil seed contact and stand emergence will be a major issue. When planting any vegetable crop no-till into cover crops, residue management is a major challenge and for all mechanically harvested crops, contamination by previous crop residue at harvest is a common concern along with harvest recovery.
No-Till Peas
Research at the University of Delaware in 2012 showed that peas planted into winter-killed cover crops yielded equal to or better than peas planted conventionally (March planting). Yields were highest in plots where forage radish or oil seed radish winter killed. No-till peas after winter killed mustards also performed well. In contrast, peas no-tilled after winter killed spring oats did not perform as well as conventionally planted peas. It should be noted that 2012 was exceptionally warm in March. Success with early no-tilled peas will depend upon soil temperature and ground cover. Lower residue systems such as winter killed radishes or soybean stubble would be best adapted for no-till peas.
No-Till Sweet Corn
Sweet corn can be successfully no-tilled. However, a major concern for early planted no-till sweet corn into decaying crop residue or killed cover crops is seed corn maggot. Even with insecticidal seed treatments, seed corn maggot can overwhelm early plantings in some conditions and reduce stands significantly. In a 2012 experiment, April planted processing sweet corn planted into killed forage radish cover crop performed poorly when compared to conventional plots due to losses to seed corn maggot. Another issue is cold soils and delayed emergence. While most processing sweet corn varieties compensate well for reduced stands, early no-till plantings are still at risk for reduced yields. No-till sweet corn will be most successful from mid-May onward. Use of row cleaners can help to make no-till more successful in early planted systems.
No-Till Lima Beans
Lima beans have been successfully no-tilled in the past. The main issue has been with residue at harvest. In 2012 trials, no-till lima beans did not perform as well as conventionally planted lima beans after wheat. This difference was most pronounced where stubble was close mowed prior to planting versus planting into standing stubble. Trials in 2013 will focus on stubble height in no-till systems after small grain with lima beans.
No-Till Snap Beans
Snap beans have been successfully no-tilled. In discussions with growers and green bean processors, green beans no-tilled into barley stubble performed very well. We will be evaluating no-till snap beans in 2013 in different stubble heights after barley. Early planted snap beans (April and May) also have the potential to be no-tilled into areas with winter killed cover crops and we will be evaluating no-till snap beans after winter killed forage radishes in 2013. Early terminated small grain cover crop would also be a possibility with no-till snap beans.
Using Vertical Tillage with Processing Vegetables
Growers are interested in the use of vertical tillage tools with processing vegetables. The success of this system will depend on the type of cover prior to planting. In 2012 research, vertical tillage prior to pea planting performed as well or better than conventional tillage in areas with winter killed forage radishes. Processing sweet corn performed equal to conventionally planted sweet corn in vertically tilled ground again after a winter killed forage radish crop. Research in 2013 will look at vertical tillage in a number of crop residues and processing crops.