Summer 1995 (v7n3)
Ann Marie Ridgely and Mark Van Horn
Summary of Final Report to UC Sustainable Agriculture Research and Education Program. 1994
This detailed survey was designed to collect information from annual crop growers that would help focus future research and extension efforts regarding the use of cover crops in field and vegetable crop systems. Participants in the survey were selected through a three step process. First, a list of all tomato and safflower growers in the year prior to the survey was obtained from the County Agricultural Commissioners in each of five counties (Yolo, Solano, Sutter, San Joaquin, Colusa). Second, a random sample of 200 growers was selected from this list and combined with a targeted list of 48 producers in the five counties who were thought to be using cover crops. From this combined list of 248 growers, 119 agreed to participate in the telephone interview.
Survey participants were asked about cover crop usage, and their perceptions of the benefits and drawbacks of cover crops. The results give a clearer picture of the current status of cover cropping in annual cropping systems in California, the types of practices currently in use for managing cover crops in these systems, the barriers to more extensive adoption of cover cropping, and areas in need of further research and extension activities. Tables 1 and 2 summarize some of the key findings from the survey.
Barriers to the Use of Cover Crops
Thirty-four of the 119 growers surveyed used cover crops. The main reasons cited for not growing cover crops were that: 1) the cover crop could not be incorporated in time for spring planting, 2) a cash crop with a direct economic benefit could be planted instead, and 3) the overall cost of growing the cover crop was too high (including seed, labor, equipment, fuel, and water costs). Those who grew cover crops responded similarly when asked why they didn't use cover crops on more of their land, noting problems with timing and economics. Those who grew cover crops and those who did not had very similar perceptions about the potential disadvantages of growing a cover crop. In addition to the three problems discussed above, farmers also mentioned increases in harmful insect populations, and tillage complications due to cover crop residue.
Table 1. Major findings reguarding cover
crop usage (n=119)
Parameter % of
Respondents
Growers using cover crops 29
Cover crop growers using:
Winter cover crops only 69
Summer cover crops only 9
Both 22
Cover crop growers farming 68
organically
Cover crop growers farming 8
conventionally
Cover Crop growers using vetch 86
(mostly purple vetch) alone or
in mix
Table 2. Desirability of certain cover
crop characteristics to growers who use
cover crops (n=34)
Characteristic % of Cover
Crop Growers
Fixes nitrogen 52
Produces high biomass 38
Competitive with weeds 21
Seed availablilty 21
Rapid growth 14
Drought tolerant 7
Flood tolerant 3
The survey data indicate that one of the major barriers to adoption of cover cropping in annual systems, especially among conventional farmers, is that they are not convinced that the benefits of cover cropping outweigh the costs. The two perceived benefits most often mentioned by farmers not currently growing cover crops were increases in soil organic matter and the addition of nitrogen to the soil and crops, benefits that can be obtained through means other than cover cropping (e.g., compost, manure, conventional fertilizers). It was interesting to note that many other potential benefits of cover cropping, mentioned by the cover crop growers, were apparently unknown or unappreciated by those who did not grow cover crops. These include: increased beneficial insects, reduced weed problems, increased water holding capacity, increased nutrient availability to the following crop, and reduced soil compaction.
Research and Information Needs
Growers' responses to questions about research and education needs indicated two areas where information is most needed: 1) New or existing cover crop varieties that can fit into a particular type of crop rotation, grow well in a particular soil or weather conditions, or possess certain characteristics (such as high biomass, fast growth, extensive root system or high nitrogen content), and 2) the effects of cover crops on various aspects of the farming system, such as soil structure, soil fertility, insect populations, and weed composition. Other categories included economic information, such as cost-benefit analyses, and operational information, such as different types of equipment and best times for planting and incorporating the cover crops.
For more information write to: Mark Van Horn, Student Experimental Farm, University of California, Davis, CA 95616.
(CI-FMCC.105)
Contributed by Chuck Ingels
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