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SUSTAINABLE AGRICULTURE RESEARCH AND EDUCATION IN THE FIELD: A PROCEEDINGS PART TWO Research and Education in the Western Region
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SUSTAINABLE AGRICULTURE RESEARCH AND EDUCATION IN THE FIELD: A PROCEEDINGS This page in the original is blank.
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SUSTAINABLE AGRICULTURE RESEARCH AND EDUCATION IN THE FIELD: A PROCEEDINGS 6 Comparative Study of Organic and Conventional Tomato Production Systems: An Approach to On-Farm Systems Studies Carol Shennan, Laurie E. Drinkwater, Ariena H. C. van Bruggen, Deborah K. Letourneau, and Fekede Workneh This chapter describes an on-going study of existing organic and conventional tomato production systems in California supported by the low-input sustainable agriculture (LISA) program of the U.S. Department of Agriculture (USDA). The goal of the project is to investigate various soil, plant, and animal processes that function within the agroecosystem as they respond to different amounts and types of inputs. In addition, economic data are being collected to document the costs and trade-offs associated with the various management systems. Such information can then be used to help assess the long-term sustainability of these production systems in terms of productivity, efficiency of resource use, reduced inputs and off-farm impacts, and maintenance of the resource base, notably, the soil. The project was initiated in 1988, and the first-season data were collected in 1989. Because this project represents a relatively unique design for comparing different production systems, the major focus of this chapter will be to discuss and evaluate the approaches taken in developing this on-farm study. TERMINOLOGY For this study, farms are considered organic when the management strategy for at least the past 3 years has emphasized reliance on biological processes. Plant nutrients are supplied primarily through the use of green manures, organic soil amendments, or both, and synthetic fertilizers and pesticides are not used. Farms that use synthetic fertilizers, pesticides, or both and that do not add organic soil amendments (other than crop residues) are considered conventional. Several sites are intermediate between these
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SUSTAINABLE AGRICULTURE RESEARCH AND EDUCATION IN THE FIELD: A PROCEEDINGS two extremes and are referred to as transitional. Most transitional farms fit into one of two categories: (1) farms that have grown crops organically for less than 3 years, or (2) organically managed farms that do not have a soil management program that includes the regular use of organic soil amendments or green manures. Although these management designations are convenient, they are still somewhat artificial, since farming practices in reality fall along a continuum rather than into discrete groups. For example, several of the conventional farmers did not spray insecticides in 1989, and in 1990 one conventional farmer used legume cover crops for nitrogen fertility but will still use synthetic fertilizers and insecticides as needed. This problem of farm categorization will be discussed further later in the chapter. BACKGROUND RATIONALE California currently leads all other states in vegetable production (Scheuring, 1983). In the Central Valley alone, the annual tomato acreage (215,000 acres) is valued at $400 million, while other vegetables, predominantly melons, occupy 245,000 acres with a value of $540 million (California Farmer, 1987). Vegetable production systems utilize large quantities of inputs such as pesticides, fertilizers, and irrigation water; therefore, a decrease in inputs in these systems could have a profound effect on California's agroecosystems as a whole. Fresh market tomato production systems have been targeted for the present study, because production from California's Central Valley represents 30 percent of the total U.S. fresh market tomato production, and most importantly, a variety of management systems exist in this region, including long-term organic tomato production. The widespread adoption of intensive conventional agriculture in California has been accompanied by the appearance of symptoms of poor soil structure (Chancellor, 1977). One symptom is decreased porosity, which can inhibit water infiltration, root penetration, and, thus, plant nutrient and water acquisition (Oades, 1984; University of California, Davis, 1984). To compensate for deteriorated soil structure or poor root development, farmers may increase applications of water, nitrogen, or both (Chancellor, 1977; E. M. Miyao, Yolo County Farm Advisor, personal communication, 1990), which, in turn, raises the potential for leaching of nutrients into groundwater (Freidrich and Zicarrelli, 1987). Furthermore, continuous cropping with vegetables and the decline in soil structure have been accompanied by increased losses caused by root diseases, such as phytophthora root rot of tomatoes (University of California, Oakland, 1985). Moreover, excessive soil nitrogen and water application have been implicated in the increased susceptibility of tomatoes to some pathogens (Ristaino et al., 1988; Schmitt-
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SUSTAINABLE AGRICULTURE RESEARCH AND EDUCATION IN THE FIELD: A PROCEEDINGS henner and Canaday, 1983; van Bruggen and Brown, in press), further compounding the problem. The beneficial effects of increased organic matter on soil structure and biology have been well documented (Chaney and Swift, 1984; Oades, 1984; Tate, 1987; Tisdall and Oades, 1982). Suppression of several plant diseases by certain soils has been attributed to high levels of microbial activity (Chen et al., 1988), and there is also evidence that use of green manures can decrease crop disease severity (Cook, 1984). Slow release of nitrogen from organic sources is reputed to lead to lower nitrate concentrations in the soil, which could potentially reduce losses via leaching, in addition to ameliorating some root disease problems. Taken together, these considerations suggest that management systems in which an effort is made to improve soil organic matter may help alleviate many of these problems. Most of the studies cited, however, refer to climates where organic matter turnover is relatively slow and increased levels can be maintained over time by appropriate management (Johnston, 1986; Reganold, 1988). Little information is currently available for semiarid irrigated systems in which high temperatures and frequent water applications favor rapid organic matter turnover. Long-term studies of cover-cropped orchard systems in California concluded that it is not possible to increase organic matter in this environment significantly (Proebsting, 1952, 1958). A corollary of this has been the assumption, therefore, that soil structural properties similarly could not be improved by efforts to enhance organic matter in California soils. In contrast, work in progress (Groody, 1990; C. Shennan, C. Griffin, and T. L. Pritchard, unpublished data) suggests that leguminous winter cover crops may improve the structural characteristics of soil and that various combinations of cover crops, tillage, and gypsum applications can improve orchard soils (Moore et al., 1989). Earlier work by Williams and Doneen (1960) and Williams (1966) also demonstrated the beneficial effects of a variety of cover crops on water infiltration in a Central Valley soil. However, it should be noted that, in general, the links between specific management practices, changes in soil properties, and their effects on plant growth have not been well established (Karlen et al., 1990). In conventional farming systems, levels of damage caused by insects remain high on many crops, even doubling in the past 30 years in some cases, despite continual development of sophisticated crop production technologies (Bottrell, 1980). Pesticides, fertilizers, and cropping patterns can drive pest population dynamics and modify damage to crops in various ways (Altieri and Letourneau, 1982; Bethke et al., 1987; Fery and Cuthbert, 1974). Insecticides can rapidly control pest species or can cause reactive outbreaks (Pedigo, 1989). Vegetational diversity in space and time may enhance the maintenance of natural enemies (Altieri and Letourneau, 1982),
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SUSTAINABLE AGRICULTURE RESEARCH AND EDUCATION IN THE FIELD: A PROCEEDINGS and for many crops, increased plant nitrogen content is associated with increased attractiveness to insect herbivores (Leath and Ratcliffe, 1974; Letourneau and Fox, 1989). Each of these factors can be influenced by farming practices that can be expected to differ among organic and conventional systems. GOALS OF THE PROJECT It is clear from the preceding discussion that crop yield, the most commonly measured attribute of agroecosystems, represents the outcome of complex interactions among soil, plant, pest, disease, and environmental and management parameters. It is the goal of this project to determine the impact of different combinations of production practices (ranging from organic and transitional to conventional) on various components of the agroecosystem. More specifically, management practices are being documented, and inputs, outputs, and a variety of soil, plant, pest, and disease parameters are being quantified for each site. A variety of questions are being addressed. For example, do soils on organic and conventional farms differ with respect to nitrogen availability, structural properties, or microbial activity? If so, are these differences reflected in patterns of plant growth and nutrient acquisition? Are the incidence and severity of root diseases or insect pests affected by these soil, plant, or management characteristics; if so, which ones are the most important? Does the structure of arthropod communities associated with the tomato crop change with different management practices; if so, are these changes reflected in differences in crop damage levels or yield loss because of insect pests? Are soils from organic farms more able to suppress the growth of root pathogens, and does this ability correlate with particular soil characteristics such as microbial activity or nitrate levels? These and other questions will be answered by the use of a hierarchical approach in which data are collected both at the field and individual plant levels. The project's main focus is to develop an understanding of the biological and ecological characterisitics of the production systems. From a practical point of view, however, it is critical to obtain sufficient information to provide a context for economic assessment of the different strategies used. To this end, enterprise budgets are being derived for each tomato production system, and the extent and nature of any financial gains or losses resulting from decisions to reduce, or cease, application of chemical fertilizers and pesticides will be evaluated. Since the economic component of the study is at a very early stage of development, it will not be discussed further.
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SUSTAINABLE AGRICULTURE RESEARCH AND EDUCATION IN THE FIELD: A PROCEEDINGS WHY AN ON-FARM STUDY? A great deal of agricultural research has been based on replicated factorial experiments conducted at experiment stations or in growers ' fields. In these experiments the effects of varying one or two factors are monitored while steps are taken to maintain all other factors constant. In this way the potential for the factors under study to affect processes of interest is clearly established. However, since the ecosystem processes of interest can potentially respond to, and interact with, many environmental and management factors simultaneously, it is not feasible to approach the study of integrated systems by use of factoral experiments. Furthermore, since there is little or no information available on organically managed vegetable production systems, it was not clear a priori what factors or management practices should initially be targeted. It seemed logical, therefore, to document the characterisitics and functioning of selected complete management systems before attempting to isolate components of these systems for more detailed examination. Significant relationships identified from the systems study can then be targeted in separate experiments to elucidate the mechanisms that are operating. Having decided upon a systems comparison, the question remains as to whether it is preferable to simulate the systems of interest in some kind of replicated experiment or to study existing farm operations. A number of farming system comparisons have taken the first approach by creating experimental organic, biological, integrated, or conventional treatments to simulate the various production systems of interest (Culik et al., 1983; Daamen et al., 1989; Doran et al., 1988; Sahs and Lesoing, 1985; Steiner et al., 1986; Vereijken, 1989; Weisskopf et al., 1989; Zeddies et al., 1986; see also R. Janke, J. Mountpleasant, S. Peters, and M. Bohlke, “Long-Term Low-Input Cropping Systems Research, ” this volume). This approach offers a number of advantages by allowing whole management systems to be studied while at the same time reducing the influence of potentially confounding variables such as soil type, surrounding habitat, and microclimate and by allowing for true replication of treatments. A further advantage of this approach is that the experimenters have full control over all management decisions. What is often the case, however, is that because of resource limitations, there must be a trade-off between the scale of the experiment and the number of replications. The sizes of the experimental plots is generally reduced to less than typical field scale to allow for reasonable replication. Alternatively, if field-size plots are chosen, then there may be little or no replication (Vereijken, 1989; Weisskopf et al., 1989). Deciding upon the scale of experimental plots is a very important consideration, since scale can have significant impacts on the results that are obtained and their interpretation. This is particularly true for studies of
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SUSTAINABLE AGRICULTURE RESEARCH AND EDUCATION IN THE FIELD: A PROCEEDINGS mobile insects (Kareiva, 1983; Letourneau and Fox, 1989) and properties that have distinctly patchy distributions, such as root disease incidence or severity (Madden, 1989). Further disadvantages of the experimental approach include the fact that the data obtained are from only a single location and may not be readily extrapolated to other sites. Also, one set of practices is used to represent a type of production system, whereas in reality, there are usually many variations on a central theme. The second approach to studying existing farm operations also brings its own set of advantages and disadvantages. Indeed, the two approaches are regarded as complementary since they can provide different kinds of information. First and foremost among the assets of the on-farm approach is that the systems under study are realistic for the present time. They represent combinations of practices and decisions made by farmers who are surviving in a world full of practical and economic constraints. Moreover, when the information is derived from multiple locations and management combinations, the robustness of any relationships that can be identified is increased. Of particular importance for this study is the fact that multiple sites could be selected that have been under organic management for various lengths of time—some for many years. In other studies a transition period has been observed following a switch to organic production methods, during which time yields may be reduced, nutrient availability may be limited, and pest problems may be increased (see the chapter by R. Janke and colleagues in this volume). Presumably, this period represents the time required for the system to attain some kind of dynamic equilibrium with respect to soil biological changes (Paul, 1984; van der Linden et al., 1987) and, perhaps, insect and weed population dynamics. Thus, the first few years of studying experimental organic systems will be spent describing the transition process. Although this is clearly of great interest, in this study the major focus is the potential for organic practices to affect attributes of the agroecosystem over the long term. By observing existing farms that have operated organically for various lengths of time, the present study provides a mechanism for doing this from the outset. Finally, working on existing farms provides an avenue for considerable interaction and information exchange between farmers and researchers. In particular, the researchers become much more familiar with the kind of decisions and compromises farmers have to make and the issues they feel are most important. Farmers, in turn, can benefit from opportunities to communicate their ideas and concerns directly to the researchers and have access to research results. Some of the approaches taken in this study to maximize this kind of two-way communication are described later in this chapter. The disadvantages associated with comparisons of existing production systems include the need to account for potentially confounding variables
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SUSTAINABLE AGRICULTURE RESEARCH AND EDUCATION IN THE FIELD: A PROCEEDINGS and the extra work load associated with the more extensive data collection this approach requires. Climate, soil type, surrounding habitat, planting date, crop cultivar, and other management details unrelated to those of interest will vary among locations and therefore must be measured and included in subsequent analyses, when appropriate, to avoid misinterpretation of the data. Provided that sites can be selected such that a similar range of these variables exists within each of the broad management categories (e.g., organic and conventional), then the effects caused by management comparisons of interest, such as organic versus inorganic nitrogen input, can be separated from those caused by extraneous variables such as soil type or planting date. Because of these considerations and the complexity of farm systems, site selection involves considerable time and effort, as does the collection of information and sampling from multiple locations and coordination of these activities with each of the farmers in turn. Finally, the fact that the investigators are not in control of the management decisions may be an asset or may prove to be problematic. On the one hand, the farmers are most knowledgeable about their fields and production options, and any decisions they make are based on the realities of physical, biological, and economic constraints. On the other hand, the decisions that are made may not be in the best interest of the project. For example, based on market considerations, a grower may decide to change the planting date, not plant the crop of interest, or cease managing a field part way through the season. An ability to compensate farmers financially for modifying their plans to accommodate the research project may help avoid such problems. While these potential problems can increase the risk and difficulty of conducting the research, none of these problems are insurmountable, and the rewards from studying existing farming systems outweigh the disadvantages. METHODOLOGICAL CONSIDERATIONS Selected components of the agroecosystem have been emphasized in previous studies on existing farms, such as specific insect abundance (Altieri and Schmidt, 1986), soil properties (Bolton et al., 1985; Doran et al., 1988; Maidl et al., 1988; Reganold, 1988; Reganold et al., 1987), or economics (Goldstein and Young, 1988), but interdisciplinary studies such as the one being conducted with tomatoes in California have rarely been attempted. Two excellent examples of integrated interdisciplinary studies are the comparison of organic and conventional farms in the Midwest United States by Lockeretz and coworkers (1981) and the study of interactions among soil properties, cultural practices, pathogens, and crop yield in existing Australian wheat farms by Stynes and colleagues (1979, 1981, 1983) and Veitch and Stynes (1979, 1981).
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SUSTAINABLE AGRICULTURE RESEARCH AND EDUCATION IN THE FIELD: A PROCEEDINGS The advantages of conducting integrated interdisciplinary studies of farming systems are numerous. A distinction is made between integrated interdisciplinary and multidisciplinary, because in many cases the latter results in two or more distinct facets of a system being investigated, with few connections being made between them. Integration of the disciplinary approaches can increase the resource use efficiency of the work, since much of the data collected is often common to many areas of investigation. More importantly, however, interactions among different components of the system can only be studied realistically in an integrated interdisciplinary framework. For example, interactions occur among soil properties, nutrient cycling, disease development, plant growth, susceptibility to insect damage, and economic return. To understand these interactions, it is critical that relevant data be collected in a manner that is useful to soil scientists, horticulturists, pathologists, entomologists, and economists. This requires considerable time in planning and discussion, a willingness to compromise, and respect for each investigator's research goals. Miller (1983), while acknowledging the necessity for team approaches to studying complex systems, has identified psychosocial and institutional barriers to truly integrated interdisciplinary research in the context of the development of integrated pest management and forest management programs. In his study, he found that the researchers had only rudimentary collaborative skills themselves and very little institutional support or incentive to form effective collaborations. In developing the study of tomatoes in California described here, many of the problems Miller identified were encountered. The need for continual dialogue and coordinated decision making throughout the project must be reemphasized. The outcome of this process is a project that is truly cooperative, representing a synthesis of ideas from researchers with diverse backgrounds. Site Selection The most important consideration in choosing study sites for the project described here was to minimize confounding variables. Clearly, what constitutes a confounding variable depends on the questions being addressed. For example, if the question relates to the role of production practices in affecting soil properties, the actual location of a farm may be of little importance, whereas parent soil type is critically important. However, if interactions between soil properties and plant growth are being examined, climatic variability among locations will influence the analysis and interpretation of the data that are collected. For an entomologist, the major variables of concern are surrounding habitat, microclimate, and field size, whereas for a plant pathologist, the presence of the relevant pathogens in fields of all management types is of primary importance.
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SUSTAINABLE AGRICULTURE RESEARCH AND EDUCATION IN THE FIELD: A PROCEEDINGS While differences in preferred selection criteria exist among the disciplines, it became obvious during the development of the tomato project that a few general criteria formed a reasonable compromise. Primary consideration needed to be given to locating farms such that the overlap among the different management types, in terms of geographic location, local climatic conditions, and range of parent soil types, was maximized. Initially, two important vegetable-producing regions were considered as study areas: the central coastal valleys of California, which produce mainly cool season vegetables, and the Central Valley, where warm season vegetables are produced. Based on the above criteria, site visits and a questionnaire were used to gather information on organic and conventional vegetable producers in both regions. The coastal region was found to have favorable characteristics for some of the project's objectives, most notably, varying levels of a potentially serious root pathogen of lettuce among different types of management systems. However, several problems existed that made this region less suitable for this kind of interdisciplinary study. Conventional and organic sites were geographically separated and experienced very different local climatic conditions. Furthermore, most organic farms were situated in isolated valleys away from other forms of agriculture. In this case, it would be difficult to separate out the effects caused by isolation and climate differences from those caused by management. Indeed, one viewpoint often stated is that organic farms require this type of isolation from other agricultural fields in order to avoid insect pest problems, although there is little evidence in the literature to support or refute this contention. In contrast, in the Central Valley there was some overlap in the locations of organic and conventional sites, and while there was a climatic gradient, it was relatively slight. Furthermore, all of the organic farms in this area had agricultural neighbors, and some were surrounded by large agricultural fields. This attribute is essential if findings from the study are to be used to make inferences regarding the impact on farms in intensively cultivated areas where organic or reduced chemical input farming is adopted. The selection of specific sites required a compromise among members of the different disciplines. All members of the research team ranked the sites in order of preference based on priorities related to their particular research interest. In this way, the sites that were most important for each discipline were sampled by the entire team. Finally, additional sites were selected for study by members of individual disciplines to address specific questions. This approach seemed like a realistic compromise, achieving the advantages of both the integrated interdisciplinary approach on a majority of sites while also providing a degree of autonomy to allow sampling methods and selection criteria for each research component to be more rigorously tested. For example, additional conventional fields were selected to be paired
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SUSTAINABLE AGRICULTURE RESEARCH AND EDUCATION IN THE FIELD: A PROCEEDINGS Findings On 21 fields, INFORM found that the soil moisture method achieved water reductions ranging from 6 to 58 percent compared with farmers ' standard practices. Most reductions fell in the range of 20 to 40 percent. The highest reductions occurred on strips where both the application rate and the irrigation frequency were reduced (Richardson and Mueller-Beilschmidt, 1988). Yields improved on 10 fields, remained the same on 6 fields, declined on 4 fields, and could not be assessed on 1 field. Of the 4 fields with lower yields, 2 cases were due to serious infiltration problems and two cases were due to irrigation delays caused by confusion about instructions to farmers. The financial benefits from lower water costs on 13 test strips ranged form $1 to $90 per acre, depending both on the cost of the water and the size of the reductions. The median cost of water per acre-foot (whether purchased or pumped) was $17. The median benefit of water reductions was $10 per acre. On eight fields irrigated through large valves in underground pipelines, there was no practical way to measure outflow. Hence, neither the volumes of water reductions nor their economic values could be estimated except in percentages. The financial benefits from higher yields on eight fields ranged from $5 to $126 per acre. All but one of these fields were planted with alfalfa, on which irrigations were reduced from two to one per monthly cutting cycle. On two more fields (one alfalfa and one tomato), farmers reported improvements in yield quality on the drier test strips, but no quantitative evaluation was possible. The combined benefits of water cost reductions and increased yield revenues ranged from $25 to $165 per acre. These occurred on the six fields where both benefits could be measured. The documented financial benefits fell short of the potential for improvements indicated by INFORM's field data. On most fields, two or three seasons of gradual changes would be needed to fully realize this potential. Moreover, reduced labor time, better assessment of new field practices, better management of equipment, and other gains reported to INFORM by farmers could not be quantified, yet they appeared to be significant in persuading farmers of the benefits of monitoring soil moisture. GYPSUM BLOCK PROGRAMS IN CALIFORNIA AND COLORADO Since the mid-1980s, when INFORM completed its research, the use of gypsum blocks has spread to more than 170 farmers in California and Colorado. Their field records and innovations provide the first broad-scale
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SUSTAINABLE AGRICULTURE RESEARCH AND EDUCATION IN THE FIELD: A PROCEEDINGS TABLE 8-2 Gypsum Block Demonstrations in California in 1989 Field Trial Result Number of Farmers Total farmer participants 45 Water and energy savings achieved High ($59/acre average) 12 Moderate ($11/acre average) 7 Low ($4/acre average) 8 Insufficient data to quantify 3 Full season used for observation and analysis 8 Underwatering or infiltration problem 3 Farmer not interested 4 SOURCE: California Association of Resource Conservation Districts. 1989. Gypsum block demonstration trial. Unpublished draft. Sacramento: California Association of Resource Conservation Districts. documentation under commercial conditions of the economic and environmental benefits of systematic soil moisture monitoring on irrigated fields. Several private and public programs have contributed to this trend. Farmers' receptivity is largely due to rising energy and water costs. The California Program, 1989–1990 SCS technicians in California watched INFORM's research with interest. At its conclusion they sought INFORM's assistance in training SCS staff to use and teach the gypsum block method. After 2 years of technology transfer involving more than three dozen additional field trials, SCS concluded that the method met farmers' needs. In 1988, with SCS's technical input, the California Association of Resource Conservation Districts won a 2-year grant of $90,000 from the California Energy Commission to teach moisture monitoring to 100 farmers in north central California (SCS Area IV). This program is developing thorough documentation of field results and farmers' reactions (California Association of Resource Conservation Districts, 1989). In 1989, all but 4 of the 45 farmers who participated in the California Association of Resource Conservation Districts program in 1989 were persuaded of the benefits of soil moisture monitoring and reported their plans to continue using gypsum blocks. Of these, about half realized significant energy and water savings during the instructional period (see high and moderate water- and energy-savings categories in Table 8-2). Most of
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SUSTAINABLE AGRICULTURE RESEARCH AND EDUCATION IN THE FIELD: A PROCEEDINGS the remainder gathered useful information about fields, crops, and practices and said they would try scheduling changes in 1990. The water reductions, where measurable, averaged nearly 1 acre-foot per acre. About 7,000 acres are currently managed with gypsum blocks in California. Colorado's Ogallala Program Colorado's Ogallala region includes more than half a million irrigated farm acres in the state's eastern plains. Parts of this area contain soils with a high clay content. Other sections belong to the sand hill country where the leaching of farm chemicals into groundwater is of growing concern. Yuma County, one of the top corn-growing counties in the United States, is located in this region. In contrast to the California program, which emphasizes surface irrigation and employs several monitoring sites per field, the program in Colorado has concentrated on center-pivot irrigation and uses only one or two monitoring sites per circle. This reduces the yearly cost of equipment and labor for monitoring to $0.50 per acre in most cases. Beginning in 1986, the Ogallala Team of SCS initiated a soil moisture monitoring program for corn and wheat producers. The 1986 work on a few fields was followed by a broader educational effort in 1987. In that year, INFORM gave essential support in the form of equipment and technical advice. Simultaneously, WAPA began a pump-testing program that quickly expended to include soil moisture monitoring. Since then the SCS- and WAPA-supported programs have branched into integrated resource management (see above). WAPA considers these programs to be models for programs in neighboring states. In three growing seasons, 1987 to 1989, moisture monitoring has spread to 65,000 irrigated acres in six Colorado counties (and 10,000 additional acres of dryland wheat). The affected acreage is probably much greater because many farmers use monitoring data from one or two center-pivot irrigation circles to manage several others. In general, farmers who monitor their fields cut back from a 90- to 100-day irrigation season to a 60- to 70-day season. Water and energy cutbacks exceeding 50 percent are not uncommon. Bruce Unruh, a corn farmer who has been in the program since 1987, reports that he has had to “throw away all the things that you were taught about irrigation and start all over.” Spurred by discoveries made with soil moisture monitoring, he has adopted a variety of new practices on irrigated corn. These include slower rotations of his center-pivot sprinkler system, the elimination of irrigation prior to planting, earlier cutoff dates in the fall, and ridge-till cultivation (which reduces herbicide use).
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SUSTAINABLE AGRICULTURE RESEARCH AND EDUCATION IN THE FIELD: A PROCEEDINGS Unruh says that $70 per acre is a conservative estimate of his cost savings from reduced inputs alone. Compared with his pre-1987 practices, his per acre costs have dropped $30 because of energy use cutbacks, $30 because of lower fuel consumption, and $10 because of reduced applications of fertilizer and herbicides. When Unruh completes his present transition to low-energy precision application sprinkler technology, he can probably anticipate another $10 per acre savings in lower energy bills, according to a local technician. Moreover, Unruh identifies many other benefits of his “revolution” for which he does not have figures readily at hand. These include higher yields, lower labor costs, and less equipment damage. Most irrigators on Colorado's eastern plains use electric pumps. In one county, Kit Carson, an added boost to the SCS- and WAPA-supported programs has come from the rural electric cooperative, K.C. Electric Association. A recent change in electricity rate structure gives farmers a powerful incentive to withhold irrigation as long as possible in the spring and to cut it off as early as possible in the late summer. The new system is most effective for both the utility and farmers when combined with soil moisture monitoring, so the K.C. Electric Association provides gypsum blocks to farmers to bring them into the SCS and WAPA programs. The cooperative extension and state energy and soil conservation programs also have links with the SCS program. Governor Roy Romer has twice presented the state's farm energy conservation award to farmers who participated in this program. A staff of four in six counties can no longer meet growing farmer demand for instruction in soil moisture monitoring. Both farmers and technical staff believe that at least half of the farmers in the Ogallala region of Colorado would adopt the method if they could observe its benefits on their own fields. These farmers would include the largest and best producers and would affect far more than half the region's irrigated acreage. The cumulative impact of their field-level changes could greatly reduce the region's energy use, slow the depletion of the Ogallala Aquifer, and curtail the runoff and leaching that degrade water quality. THE ROLE OF EDUCATIONAL ADVISERS AND AGENCIES SCS technicians in California and Colorado agree that soil moisture monitoring with gypsum blocks sells itself. However, they emphasize the importance of initial instruction that includes the following components as being essential for getting farmers to the takeoff point over one or two seasons: demonstration on farmers' own fields; one-on-one teaching (several meetings a year);
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SUSTAINABLE AGRICULTURE RESEARCH AND EDUCATION IN THE FIELD: A PROCEEDINGS farmer participation as early as possible in installing gypsum blocks and collecting readings; and patience; farmers “look before they leap,” and it sometimes takes a while for them to respond. Soil moisture monitoring opens a new world to both farmers and technicians, and they learn together. This creates a strong foundation for the development of integrated farm management plans based on site-specific conditions and farmers' actual questions and needs (Richardson et al., 1989). PRODUCERS OF GYPSUM BLOCKS There are several producers of gypsum blocks and meters in the United States, chiefly the following: Beckman Industrial Corporation, Cedar Grove, New Jersey Delmhorst Company, Towaco, New Jersey Electronics Unlimited, Sacramento, California Irrometer Company, Riverside, California Soilmoisture Equipment Corporation, Santa Barbara, California Soil Test Incorporated, Denver, Colorado Different models of gypsum blocks and meters perform differently. No technical standards have yet been developed for evaluating and comparing their features. Electronics Unlimited supplies the blocks and meters that were used in all of INFORM's work and continue to be used by SCS in California. The Delmhorst Company has been the leading supplier of the blocks and meters used in the program in Colorado. THE PUBLIC ROLE Soil moisture monitoring is a practical route to lower production costs for irrigated farms and more effective protection of the environment in the western United States. It deserves increased public support of several kinds. Research is needed to establish technical standards to enable farmers and technicians to choose wisely among the available soil moisture sensors, which vary in sensitivity, uniformity, longevity, and price. Field demonstrations targeted in areas plagued by drainage and contamination problems could help to identify practical applications of soil moisture monitoring as components of regional water quality plans. The training of field staff in major federal and state agencies would give farmers much broader access to instruction in soil moisture monitoring.
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SUSTAINABLE AGRICULTURE RESEARCH AND EDUCATION IN THE FIELD: A PROCEEDINGS Modest financial assistance to farmers during an initial instructional period of 1 or 2 years would encourage more farmers to try soil moisture monitoring. Once farmers see its benefits on their own fields, they are generally willing to carry the method's full costs. REFERENCES California Association of Resource Conservation Districts. 1989. Gypsum block demonstration trial. Unpublished draft. California Association of Resource Conservation Districts, Sacramento, Calif. Richardson, G., and P. Mueller-Beilschmidt. 1988. Winning with Water: Soil-Moisture Monitoring for Efficient Irrigation. New York: INFORM. Richardson, G., J. Tiedemann, K. Crabtee, and K. Summ. 1989. Gypsum blocks tell a water tale. Journal of Soil and Water Conservation 44:192–195.
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SUSTAINABLE AGRICULTURE RESEARCH AND EDUCATION IN THE FIELD: A PROCEEDINGS 9 Reactors' Comments Research and Education in the Western Region Dale R. Darling Many of the processes proposed for changing agriculture, including low-input sustainable agriculture (LISA), sustainable agriculture, alternative agriculture, best management practices, integrated pest management, and integrated crop management, are used by many highly efficient, profitable farm operators today. Agriculture was changing before LISA; however, the pace and intensity, as well as the focus, have quickened since LISA was introduced. Some of the products developed by DuPont involved in this change are described below: methomyl (Lannate) was used for insect control in soybeans based on economic thresholds in the early 1970s; it is now referred to as integrated pest management; linuron (Lorox) herbicide was used for no-till soybeans in the early 1970s: chlorsulfuron (Glean) herbicide, the first of a family of new low-level, low-environmental-impact herbicides, is a virtually nontoxic crop protectant for cereals; and low-level, low-environmental-impact pyrethroid insecticides, such as estenvalerate (Asana), are used along with low-level herbicides to reduce significantly the quantity of pesticides placed in the environment. Through change comes opportunity. Industry looks forward to the challenges, changes, and opportunities for a more environmentally sound, so-
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SUSTAINABLE AGRICULTURE RESEARCH AND EDUCATION IN THE FIELD: A PROCEEDINGS cially acceptable, and more profitable agriculture system for U.S. farmers and their customers, the consumers. In reviewing these comments, the reader must keep in mind my biases about agriculture. First, agriculture is fundamentally sound and very productive, with abundant opportunities for improvement through scientific discoveries. However, the starting point for initiating change should be with the highly efficient, profitable, environmentally conscientious farmers who have incorporated the results of 90 years of agriculture research and education into their profitable enterprises. Second, to create change efficiently and effectively, all of those involved in the input side of agriculture should be included in the process along with those who envision the need for dramatic changes. REACTIONS Below are some of my general reactions to the chapters presented in the section, “Research and Education in the Western Region.” In general, there is no argument with the concepts and principles presented in the sustainable agriculture focus. There appears to be more of a spirit of cooperation developing between most facets of agriculture and production; research and education; and government, industry, and producers. Some still need to understand that crop protectants are marketed for the purpose of managing excesses in pest populations; they are tools, like a plow, a cultivator, or a hoe. A team approach to research, demonstration, education, marketing, and production is the most economical and rapid method for creating change. The highly efficient, profitable farming enterprises most rapidly adopt new ideas. The following are specific responses to the chapters in this section. In their opening, John Gardner and colleagues (“Overview of Current Sustainable Agriculture Research”) asked, “if sustainable agriculture is so good, why is it so controversial? ” The concepts presented in that chapter are on target in relation to the title. However, if the leading question was answered, I missed the point. It is possible that the controversy Gardner and colleagues referred to is a result of the lack of communication between those involved in the established systems of research, education, and production and those desiring to change the systems. Robert Papendick, in “STEEP: A Model for Conservation and Environmental Research and Education, ” showed that STEEP is truly a model of cooperation between producers, researchers, conservationists, ex-
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SUSTAINABLE AGRICULTURE RESEARCH AND EDUCATION IN THE FIELD: A PROCEEDINGS tension personnel, commercial consultants, and retailers, as well as those involved in many production agriculture input industries, including the equipment, seed, fertility, and crop protection industries. The results are the proof. The project described by Carol Shennan and colleagues in “Comparative Study of Established Organic and Conventional Tomato Production Systems in California: An Approach to On-Farm Systems Studies” could possibly benefit from involvement in the planning process by producers and input suppliers already involved in tomato production in the central coastal and interior Central Valley of California (Yolo, Sutter, and Sacramento counties). Those researchers who are currently involved in the project include a plant physiologist, a plant pathologist, a zoologist, an ecologist, as well as an economist. The model of cooperation between all entities presented by Papendick in the STEEP program should be considered. I suggest that the project be discussed with commercial agronomists, consultants, and other specialists currently involved in commercial tomato production in these regions. They are valuable sources of experience and information. Gail Richardson, in “Soil Moisture Monitoring: A Practical Route to Irrigation Efficiency and Farm Resource Conservation,” provided an excellent demonstration of what appears to be a relatively low-cost, low-technology, practical approach to measuring soil moisture and plant response. The intriguing thing she noted is the involvement of farmers, researchers, and educators with the suppliers of the technology in the field. The approach to developing the technology, as well as the simultaneous transfer of the technology, is similar to the approach used in the agricultural chemical, seed, and fertilizer industries, as well as that demonstrated in the chapter by Papendick on the STEEP program. In the presentation of Kevin Gamble at the workshop (not included in this volume), “A National System for Sustainable Agriculture Information Dissemination,” it was difficult to understand the technological elements of the concepts that he presented. It was easy to grasp the theories themselves. They should be carried out. There is an important link in the technology transfer process that should be considered in the development of a sustainable agriculture system. Regardless of where farmers get their information, for example, media, extension, other farmers, commercial representatives, a local coffee shop, or field days, there is one vital last point where information is condensed and transferred: that is, the equipment, seed, fertilizer, and crop protection retailers; consultants; or contract applicators where farmers exchange their dollars for information, products, or services. I hope all participants will find these suggestions constructive and helpful.
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SUSTAINABLE AGRICULTURE RESEARCH AND EDUCATION IN THE FIELD: A PROCEEDINGS A Farmer's Perspective Robert A. Klicker I am pleased to be able to react to some of the information presented in this volume (see the chapters by R. James Cook, Gail Richardson, Robert I. Papendick, Carol Shennan, and Kevin Gamble). The information in these chapters was presented clearly and accurately and can be incorporated into use on my farms, which are located in four areas with different soil types and rainfall amounts. I am concerned that results of the type of research discussed in those chapters take years before they are available to farmers. The results of this kind of research should be directed and incorporated into complete farm systems as soon as possible after they become available. James Cook's documented microbial research and his opinions on soil microbial action are the major key to sustainable agriculture. The bulletin “Long-Term Management Effects on Soil Productivity and Crop Yield in Semi-Arid Regions of Eastern Oregon” (Columbia Basin Agricultural Research Center, 1989) expands on Cook's points. This bulletin explains in detail the long-term soil depletion and reduced crop yield problems for which there have been no corrective solutions since 1931. Cook 's research is a major contribution to some of the corrective solutions that can be used in a complete farm system. Gail Richardson's chapter documenting her 7 years of on-farm water conservation technology with the use of gypsum blocks is also a major key for sustainable agriculture. Richardson documented a 20 to 40 percent savings of water. She also discussed methods that can be used to inspire farmers to apply the information she has gathered to their irrigation techniques. She proved that these methods are an economic educational tool that can be widely accepted by farmers and that can help them to understand the movement of water, soil plow pans, or compaction and when there is too much or not enough water in the root zone. STEEP coordinator Robert Papendick reviewed the excellent progress that has been accomplished in reducing soil erosion, which leads to improved water quality. I was also pleased to read a discussion of the plans for STEEP II research. James Cook has stated it all correctly when he says, “Scientists are rewarded for discovering and working out mechanisms but not for carrying this technology into application.” Experience has proven that piecemeal, conflicting data will not build a sustainable agriculture system. All sustainable agriculture could be lost if complete farm systems research does not zero in on water harvesting, organic matter, and soil tilth research. A complete sustainable agriculture system (including use of the correct amount of
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SUSTAINABLE AGRICULTURE RESEARCH AND EDUCATION IN THE FIELD: A PROCEEDINGS nutrients plus use of soil cation-exchange ratios, correct tillage, water, and air) promotes increased microbial biomass and increased organic matter. Organic matter has three times the water- and nutrient-holding capacity than clay does. Increases in organic matter promote higher yields and, often, higher-quality products. Because organic matter has a higher waterholding capacity, soils with good organic matter levels are less likely to erode. I know from my own and my neighbors ' soil tests that organic matter levels can be increased slowly and systematically by using commercial fertilizers and incorporating stubble with the correct conventional tillage tools. For each farm system, of course, there are slight variations in the methods that are used to stop erosion and increase organic matter. However, many of the basic methods stay the same. Soil tests were performed on 15 different fields at three separate farms. These fields have had a definite, substantial increase in organic matter in 4 to 5 years. The normal erosion on these fields, which have 10 to 40 percent slopes, has been completely controlled without the loss of yield. It is my opinion that the entire U.S. agricultural community should move toward the complete farm research system concept, incorporating James Cook's research, Gail Richardson's water conservation research, farmers' own on-farm research, and other existing technologies. Successful sustainable agriculture can be achieved by working to increase organic matter and the microbial biomass, by correcting soil tilth, and by stopping erosion while using conventional fertilizers and tillage tools. To accomplish this, the valuable information from the scientific community that is presented in this volume must be coordinated and shared with U.S. farmers in a more timely fashion. REFERENCE Columbia Basin Agricultural Research Center. 1989. Long-Term Management Effects on Soil Productivity and Crop Yield in Semi-Arid Regions of Eastern Oregon. Bulletin No. 675. Pendelton, Oreg.: Agricultural Research Service, U.S. Department of Agriculture, and Oregon State University Agricultural Experiment Station.
Representative terms from entire chapter: