Green and animal manure use in organic field crop systems

Dual-use cover/green manure (CGM) crops and animal manure are used to supply nitrogen (N) and phosphorus (P) to organically grown field crops. A comprehensive review of previous research was conducted to identify how CGM crops and animal manure have been used to meet N and P needs of organic field crops, and to identify knowledge gaps to direct future research efforts. Results indicate that: (a) CGM crops are used to provide N to subsequent cash crops in rotations; (b) CGM-supplied N generally can meet field crop needs in warm, humid regions but is insufficient for organic grain crops grown in cool and sub-humid regions; (c) adoption of conservation tillage practices can create or exacerbate N deficiencies; (d) excess N and P can result where animal manures are accessible if application rates are not carefully managed; and (e) integrating animal grazing into organic field crop systems has potential benefits but is generally not practiced. Work is needed to better understand the mechanisms governing the release of N by CGM crops to subsequent cash crops, and the legacy effects of animal manure applications in cool and sub-humid regions. The benefits and synergies that can occur by combining targeted animal grazing and CGMs on soil N, P, and other nutrients should be investigated. Improved communication and networking among researchers can aid efforts to solve soil fertility challenges faced by organic farmers when growing field crops in North America and elsewhere

Combining Reduced Herbicide Rates and Cultivation for Effective Weed Control in Corn

NYS IPM Type: Project ReportDemonstrations of banded herbicides and cultivation were conducted at one location in New York. Despite extensive on-station research showing that banded herbicides and cultivation can result in yields equivalent to broadcast herbicides, even growers who already cultivate rarely use banding of herbicides to reduce chemical application rates and costs. Since reduced rates of herbicides are now legal in New York, our demonstration was modified this year to include 1/3 rate of herbicide plus cultivation. We believe that one reason that growers have not used banded herbicides is that equipment changes or purchases are necessary, whereas reducing rates of a broadcast spray requires no new equipment or arrangement of current equipment

Managing Quackgrass as a Cover Crop in Corn

NYS IPM Type: Project ReportBackground and justification: A field experiment was to be conducted in 1998 at a site with heavy quackgrass infestation in NY to determine optimal weed control conditions and quackgrass suppression strategies to manage it as a cover crop in corn. The perennial and pernicious weed quackgrass (Elytrigia repens) can be a costly and difficult weed to control in field corn

Managing Quackgrass Infestations as Cover Crops in Herbicide-Resistant Corn

ReportQuackgrass (Elytrigia repens (L.) Nevski) is an invasive weed – not normally considered to be a desirable cover crop. However, its high nutritional value makes this weed more tolerable in alfalfa (Medicago sativa L.) than in corn (Zea mays L.). Growers typically attempt to eradicate quackgrass from corn fields, but manage this weed less aggressively in alfalfa, where it contributes to hay quality and yield. The objective of this study was to evaluate herbicides for use in herbicide-resistant corn which could: 1) suppress quackgrass to minimize its effect on corn silage yield, 2) leave adequate quackgrass residue to control erosion (act as a good cover crop), and 3) leave quackgrass as a grass companion crop for alfalfa. In this first year of the study, the weather was unusually dry, and the presence of quackgrass hurt corn yields in all treatments. Quackgrass did, however, provide sufficient ground cover in many of the treatments

Using Herbicide-Resistant Corn Hybrids to Establish an Alfalfa Cover Crop

ReportRecent introductions of herbicide-resistant corn hybrids in New York offer opportunities for corn growers to produce silage corn with little erosion, and to reduce herbicide and tillage inputs. These opportunities result from the possibility of growing an alfalfa cover crop in corn. A common rotational practice in N.Y. is to grow 3 to 4 years of corn, followed by 3 to 4 years of alfalfa. In the proposed system, alfalfa would be seeded at the start of the last year of corn in each cycle, would grow as a cover crop during the season, and would continue growth after corn silage harvest. Though this system has been tried in the past, one seemingly insurmountable difficulty was the lack of ability to control weeds, either chemically or culturally, without damage to either the corn or the alfalfa crop. The introduction of some herbicide-resistant corn hybrids means that weeds can now be controlled by herbicides which are naturally safe on legumes and safe on the resistant corn hybrids

Managing Quackgrass Infestations as Cover Crops in Herbicide-Resistant Corn

NYS IPM Type: Project ReportQuackgrass (Elytrigia repens (L.) Nevski) is an invasive weed - not normally considered to be a desirable cover crop. However, its nutritional value makes this weed more tolerable in alfalfa (Medicago sativa L.) than in corn (Zea mays L.). Growers typically attempt to eradicate quackgrass from corn fields, but manage this weed less aggressively in alfalfa, where it contributes to hay quality and yield