Final Report for LS96-079
Project Information
Cattle and watermelons are grown extensively throughout the southern United States. Some farmers produce both commodities, but no one produces both crops on the same land in the same year. Farm diversification with cattle and watermelons would improve cash flow, minimize risks and lead to farm stability and sustainability.
The main disadvantage to cow-calf operations is that the income from small and medium sized cattle farms is not sufficient to maintain a desirable standard of living. Most farms in southeastern Oklahoma are 100 to 300 acres in size, and normally produce about $10,000 to $50,000 of gross farm income, with net profit being a fraction of the gross income.
Watermelons can produce gross returns in excess of $1000 per acre. While watermelons normally produce more income per acre than do cattle, much of the land planted to watermelon is subject to erosion when not kept under a plant cover. Watermelons should be grown in a given field no more than 1 out of 4 years to prevent soil-borne diseases that will reduce, or eliminate, crop yields. Because of this, watermelon growers need access to at least four times the amount of their annual watermelon acreage. Pasture land is unlikely to have a watermelon disease problem, and is thus desirable as a site for rotation with watermelons. However, most cattle farmers are unwilling to convert a permanent pasture into watermelons, and then re-establish the pasture after melon harvest is completed.
Most agriculture in southeastern Oklahoma involves cow-calf operations. Rainfall and temperatures are conducive to grass production, and markets are available throughout the year. Cattle production is also desirable from an environmental standpoint. Cultivated soils in the area are highly erodible by both wind and water, but permanent pastures keep vegetation on the soil and thus greatly reduce soil erosion. In Texas, watermelon producers can plant earlier and harvest later than can those in Oklahoma. This allows more flexibility in designing a multi-cropping system than could be done in Oklahoma.
A system is needed that would allow melon production in an established pasture or meadow for one year without damaging the stand of grass for the following years. An even better system would allow for production of both pasture grasses and watermelon on the same land in the same year. The purpose of this project has been to determine if watermelon and bermudagrass pastures can be grown in the same field in the same year. One approach to answering this question was to grow watermelon in strips in a perennial pasture or meadow. Only a small portion of the pasture was tilled and planted with melons, and the pasture was then allowed to return to grass. With this system, cattle producers can diversify their operations, minimize risk, and improve farm profits. Watermelon producers can reduce soil erosion and have a disease-free site for crop rotation.
Research has been conducted for three years in Oklahoma and Texas to develop such a system. Fields of bermudagrass have been used to grow both hay and watermelons. One technique has been to plant watermelons in the field as early as possible in the spring. Hay is grown between the plots at the same time, and after the melons are harvested, the entire field is allowed to revert to bermudagrass. Another technique is to get one cutting of hay from the field in the spring, and then after the hay is harvested, to plant strips of watermelon into the grass stubble. Grass is allowed to grow between the strips while the watermelons are being grown. The main difference in these two techniques is the timing of harvest for each crop. The first technique involves harvesting watermelons prior to hay, while the second technique involves harvesting hay prior to watermelons. Either technique has potential, and the choice of techniques is primarily dependent upon the market that watermelon growers are attempting to meet.
After three years, we have demonstrated that both hay and watermelon can be harvested from the same field in a single year. The tilled strips that were planted with watermelons in one year may be covered with bermudagrass later during the same year, and will certainly be covered with grass the following year. We have not encountered a noticeable change in either insect or disease occurrence with any of the treatments in this system.
After three years of research, the main limitation to watermelon growth seems to be weed control. Bermudagrass may be classified as a weed when it interferes with watermelon production, even though it is also classified as a crop when grown between the tilled strips or when it is grown before or after the crop of melons. If grasses are completely controlled in the tilled and planted row, broadleaf weeds may become a problem within the row.
One other concern that needs to be further investigated involves pollination of the watermelon. Observations in both Texas and Oklahoma have led us to believe that there may be insufficient pollination. This observation was particularly noticeable in 1998. If insufficient pollination did occur, there are two likely explanations. The first is that there may have been insufficient numbers of bees. During the past two or three years, there has been a dramatic decline in the number of native bees throughout the entire country, including Texas and Oklahoma. A reduced number of bees could have led to insufficient pollination. A second explanation, assuming that the number of bees was sufficient, was that the watermelon flowers were masked by surrounding grasses, and thus did not attract a sufficient number of bees per flower. A third explanation is that the extremely high temperatures that occurred during the time of fruit set in 1998 were detrimental to fruit set, even if a sufficient number of bee visits did occur. Further investigation is needed to determine the cause of low fruit set which occurred in 1998.
The benefits expected from this project have been achieved. The system that has been developed will allow multi-cropping of both bermudagrass and watermelon. This system combines the advantages of a perennial crop with an annual crop. The system encourages crop diversity, and utilizes the advantages of crop polyculture. The system allows the production of a crop that is normally grown by clean culture without subjecting vast amounts of soil surface to erosion by wind or water. The system allows crop rotation within a given field, and thus lessens the chance of pathogen or parasite accumulation. The system allows production of a high value horticultural crop and a perennial soil-covering forage from one field in one year.
All project objectives have been met. Three years of results have been obtained at both the Texas location and the Oklahoma location. These results have allowed us to rank the effectiveness of treatments, and to modify treatments. Treatments have been dropped, added, and modified to develop the best production system.
Plastic mulches have been found to produce high yields of watermelons, but they do not fit well with a systems approach to bermudagrass and watermelon. Removal of the plastic was so difficult that other means of weed control were explored. Certain combinations of cultivation and herbicide have been tested that will allow watermelons to be produced at a level similar to that which is expected in a conventional clean-tilled system. The system developed during the first two years of research has been demonstrated at on-farm locations.
The major problems encountered in carrying out this project have involved weather extremes. The last three years in Texas and Oklahoma have included record-breaking heat and drought. This project is based on multi-cropping two un-related crops, and the timing for each phase of each crop is critical. Weather extremes have made it difficult to develop the best strategy for timing the planting and harvest of each crop in the system. A cropping sequence that is developed for an average year might or might not work well under weather patterns that differ greatly from the normal pattern.
The Southern SARE has not been an impediment to the project objectives. Without funding through the SARE program, the project would never have been completed.
Develop techniques for growing watermelon in tilled strips in a permanent pasture.
Cattle and watermelons are grown extensively throughout the southern United States. Production techniques and markets for both commodities are well established, but weather extremes, market fluctuations, and diseases or insects can be devastating to farmers that rely totally on one crop. Some farmers are involved in production of both commodities, but no one attempts to produce both crops on the same land in the same year. Farm diversification with cattle and watermelons would improve cash flow, minimize risks and lead to farm stability and sustainability.
The main disadvantage to cow-calf operations is that the income from small and medium sized cattle farms is not sufficient to maintain a desirable standard of living. Most farms in southeastern Oklahoma are 100 to 300 acres in size, and normally produce about $10,000 to $50,000 of gross farm income, with net profit being a fraction of the gross income. Thus, few cattle farms in southeastern Oklahoma are capable of supporting a family at a realistic standard of living.
Watermelons can produce gross returns in excess of $1000 per acre. While watermelons normally produce more income per acre than do cattle, much of the land planted to watermelon is subject to erosion when not kept under a plant cover. Watermelons should be grown in a given field no more than 1 out of 4 years. If watermelons are grown in the same field in consecutive years, there is a good chance that soil-borne diseases will reduce, or eliminate, crop yields. Because of this, watermelon growers need access to at least four times the amount of their annual watermelon acreage. Pasture land is unlikely to have a watermelon disease problem, and is thus desirable as a site for rotation with watermelons. However, most cattle farmers are unwilling to convert a permanent pasture into watermelons, and then re-establish the pasture after melon harvest is completed.
In southeastern Oklahoma, most agriculture is in the form of cow-calf operations. Rainfall and temperatures are conducive to grass production, and markets are available throughout the year. Cattle production is also desirable from an environmental standpoint. Cultivated soils in the area are highly erodible by both wind and water, but permanent pastures keep vegetation on the soil and thus greatly reduce soil erosion. In Texas, watermelon producers can plant earlier and harvest later than can those in Oklahoma. This allows more flexibility in designing a multi-cropping system than could be done in Oklahoma.
A system is needed that would allow melon production in an established pasture or meadow for one year without damaging the stand of grass for the following years. An even better system would allow for production of both pasture grasses and watermelon on the same land in the same year. The combination of watermelons with cattle will offer such a system to area farmers.
Very little work has been attempted relative to the objectives of this proposal. There is no information concerning any attempts to grow watermelons in strip-tilled areas in a permanent pasture. However, the concept of strip-tillage, living mulches, and maintenance of permanently grassed areas between rows has been examined with other crops, including corn (Elkins et al., 1977; Elkins et al., 1978), soybeans (Dadson et al., 1975), coffee (Chandler et al., 1969), fruit trees (Baxter, 1970), and strawberries (Newenhouse and Dana, 1989). Standing vegetation has been used for windbreaks for fruit and vegetable crops (Baker, 1977). In a broader sense, conservation techniques have been tested for vegetable production (Hoyt et al., 1994), but not in the sense of strip till in permanent pastures.
Strip tillage has also been examined for vegetable production systems (Loy et al., 1987), but the crops were with pepper and squash in New Hampshire, and the between row area was planted with blue grass, fescue, ryegrass, and clover. While the concept is similar to that in this project, the crops and the grasses were so different from watermelon and bermudagrass that the results are not applicable to this project. In Oklahoma, we have examined conservation tillage for various vegetable crops (Roberts and Cartwright, 1991a; 1991b; 1991c; Nelson et al., 1991), and groundcovers have been tested with peach trees (Huslig et al., 1993). While the concept is similar, the crops and the ground cover have been totally different from what was accomplished in this project.
Although there are similarities in concept between this and other projects, no other work has been reported with watermelons in strip tilled fields. Also, no work has been reported combining vegetable production of any sort into a bermudagrass pasture setting.
Research
The study was conducted in Oklahoma and Texas for three years, 1996 through 1998. Experiments established at university research stations in 1996 provided preliminary information, and the results were used to further refine treatments in 1997 and 1998. All treatments were designed with the objective of gathering information about the value of various cultural management techniques for growing watermelon in strips in a permanent pasture. Small scale replicated plots were established in 1996 and maintained for the following two years. On-farm demonstrations were conducted in 1997 and 1998.
In Oklahoma, a field was sprigged with bermudagrass in the fall of 1995 and was also seeded with bermudagrass in the spring of 1996. This field was maintained through1998. In the spring prior to treatment initiation, all plots were mowed. Hay was raked and baled. The hay was then removed from the field. Strips 6 feet wide were tilled in preparation for the following treatments. The strips were on 18 ft centers, and plot length was 45 ft. The following treatments were installed in early June in 1997 and 1998.
1. Control treatment: Weedy check, no weed control attempted.
2. Cultivation early. Poast (sethoxydim herbicide) when needed.
3. Cultivation early. Treflan (trifluralin herbicide) at 3 leaf stage.
4. Cultivation early. Treflan at 3 leaf stage. Poast when needed.
5. Cultivation as long as vine growth permits.
6. Cultivation as long as vine growth permits. Treflan at last cultivation.
7. Cultivation as long as vine growth permits. Treflan at last cultivation. Poast when needed.
8. Clean control: Cultivation plus Treflan plus Poast plus hand-hoeing as needed.
Watermelons (cv. Sangria) were seeded in a greenhouse and later transplanted into the above treatment plots. Standard fertility and pest control practices were followed. At harvest, measurements were taken of watermelon number and weight. Shortly after harvest, measurements were taken on one foot intervals to determine whether the soil at that point was covered by grass, broadleaf weeds, watermelons, or bare soil.
In Texas, at the Stephenville Research and Extension Center (SREC)
In October, 1997, 24 plots, 30' long and 30' center to center were laid out between the plots from the 1996 and 1997 seasons, in areas of the field which had been in bermudagrass for three years. The fall herbicide treatment was sprayed with glyphosate (2%). In March, 1998, the plots were plowed with a chisel and then rototilled. Fertilizer at 80-80-80 (lbs./A. N-P205-K20) was tilled into the plots on 1 May. Raised beds were constructed and covered with the appropriate polyethylene mulch, where needed, on 5 May. On 18 May ‘Pinata’ watermelon transplants were transplanted into the beds at 30" within row spacing. A beehive was placed near another watermelon trial, about 0.25 mile away.
Treatments were:
Mechanical cultivation M
Polyethylene mulch (1.25 mil) P
Biodegradable polyethylene mulch B
Herbicide (sethoxydim) H
Fall herbicide F
Sudan hay mulch HA
Weeds in M plots were removed by hoeing on 11 June. Sethoxydim herbicide was applied to H plots on 11 June, using a manually operated backpack sprayer. It was used at a rate of 1% with 1% Surfel, a crop oil. Grass for hay was sampled in late June. Four 30 ft grass samples were weighed and subsamples were weighed, dried at 68 C for 3 days, re-weighed, and tested for nutrient levels. If watermelon beds are 10' wide and spaced at 30', they will take up 1/3 of the field. Therefore, only an area of 28,750 sq.ft. in each acre is available for hay harvest. This figure was used to estimate hay yields.
All watermelons estimated to weigh at least 4 lbs. were harvested, counted, and weighed on 2 July. Those with cracks or other damage were counted as culls. Yields per acre are based on plots 30' apart (center to center) tilled into grass.
At a Comanche County-Grower’s Field (COM)
Strips (10' wide) were chiseled into the coastal bermudagrass field, between the 1997 plots. Fertilizer was broadcast on all plots at a rate of 100-100-100 (lbs./A. N-P205-K20) and incorporated on 29 May. Plots were 40' long. On 20 May beds (36" wide) were constructed and polyethylene mulch and drip tape applied.
Treatments were:
Mechanical cultivation M
Polyethylene mulch P
Biodegradable polyethylene mulch B
Herbicide H
Fall herbicide F
On 22 May, ‘Pinata’ watermelon transplants were planted into all beds. All weeds in M plots were removed by hoeing on 11 June. Sethoxydim herbicide (same rate as SREC) was applied to H plots on 16 July.
Watermelons were harvested in the same manner as those at SREC on 7 July. Bermudagrass was sampled in mid-Aug. and samples were taken in a similar manner to SREC.
Oklahoma - The entire mowed area of the study was about 1.8 acres, and produced five round bales of hay in 1997 and nine round bales of hay in 1998, with each bale weighing about 800 pounds. This hay yield was similar to what would have been obtained from a typical hay meadow. Thus, a satisfactory harvest of hay was obtained before the watermelons were planted.
In 1996, superior watermelon yields were obtained when either a clean control or plastic mulch was used as treatments. While the plastic mulch suppressed weed growth and provided high yields, it was very difficult to remove the plastic from the plots at the end of the year. While all farmers who use plastic mulch have experienced this problem, the difficulty was magnified in this study because of the overgrowth of bermudagrass which partly covered the plastic and prevented degradation. At the same time, the grass made physical removal of the plastic extremely difficult. Because of the difficulty of plastic removal, plastic mulches were dropped from the study in Oklahoma in 1997 and 1998.
In 1997, the greatest yield of watermelon came from the clean control (trt #8), which was maintained with cultivation, herbicides, and hand hoeing. While this treatment gave a high yield, the inputs were substantial, and the amount of hand hoeing would probably have offset the increased yield. The next highest yield came from the two treatments that consisted of cultivation, Treflan, and Poast (trt # 4 & 7). The next best yielding treatment consisted of cultivation and Poast, without Treflan (trt # 2). While the ranking of these treatments was in the order we have listed, these treatments were not statistically different from each other. Following these treatments, the next highest yield came from plots that were treated with cultivation and Treflan (trt # 6). The treatment with the lowest yield, other than the weedy control plot, was the cultivation alone plot (trt # 5).
The yields were typical of what a farmer might receive from a conventional watermelon field. Most treatments produced in the range of 4 to 5 tons of watermelons per acre. While these yields may seem low, it is important to recall that only one third of the total land area was tilled and planted with watermelons (6 out of 18 feet). If the watermelon yield was calculated solely on the basis of the tilled area, the yield would have been in the range of 12 to 15 tons per acre, which is higher than the average watermelon yield in Oklahoma.
It is also important to recall that one cutting of hay was obtained from the field before the watermelons were planted, that the hay yield was similar to what a farmer might have received, that very little soil was uncovered at any time during the growing season, and that after harvest the field was already replanted with bermudagrass.
In 1998, yields of all treatments were very low. Oklahoma recorded record-breaking heat and drought during the entire summer, and the weather extremes caused watermelon production to be very low in other adjacent experiments as well. The ranking of treatments was very similar to that of 1997, but the magnitude of the yield was much lower than that received in 1997. In 1998, the greatest yield of watermelon came from the clean control (trt #8) and from the treatment with cultivation, Treflan, and poast (trt #7) (Table 1). The four treatments with the greatest yield all contained poast, while none of the other treatments contained Poast.
Grass regrowth was also a measurement of interest. For this system to be successful, the tilled strips must become quickly recovered with bermudagrass. Measurements of soil cover taken just after watermelon harvest indicated that the weedy check plots had more grass cover than did any other plot. All of the treatments containing Poast had less grass cover than did any of the treatments without Poast.
The treatments with the greatest regrowth of bermudagrass tend to also be the treatments with the lowest watermelon yield.
Texas - In 1997, in Texas, the treatments focused on cultivation and mulches. Plastic mulch was maintained as a treatment in Texas so that a comparison could be made between plastic mulch and organic mulch as mechanisms for weed control. The greatest yield came from plots with either polyethylene mulch or degradable mulch. The yield from these plots was about 2-3 tons per acre. With about 10 feet out of 30 feet being tilled, the yield from the tilled area alone would have been in the range of 6 - 9 tons per acre, which is an average yield.
The treatment that consisted of mechanical cultivation alone was about one half ton per acre, which would not be considered an acceptable yield. The herbicide sethoxydim (Poast) alone treatment was also unsatisfactory. However, the combination of cultivation and herbicide yielded nearly two tons per acre, or six tons per cultivated acre. The plots that received a hay mulch did not yield as well as the synthetic mulched plots. Likewise, they did not yield as well as the plots that received cultivation and herbicide.
In 1998, yields and fruit weights from both types of polyethylene-mulched plots were generally higher than most other treatments, although there were few significant differences at COM. (Tables 2 and 3). These treatments also had the lowest percentage of culls. Most of the culls in this and the other treatments were due to small size and misshapen fruit, probably due to incomplete pollination.
Mechanical cultivation was similar to P and B in all parameters at both sites except undamaged and total yields at SREC. Yields and fruit weights of herbicide treatments tended to be lower than P, B, and M. Culls were also considerably higher. Sethoxydim is an excellent selective herbicide. However, on coastal bermudagrass it tends to work very slowly. Therefore, it should probably be applied earlier in the season than we applied it. Due to an exceptionally dry May, we did not seem to have as much early grass growth as in most years. However, irrigation of the transplants, combined with a rain in early July, resulted in grass growth. The other problem is that, when the coastal bermudagrass was controlled, broadleaf weeds grew well, competing with the melons as in the fall herbicide plots. Perhaps the use of a labeled pre-emergent would be appropriate in this system.
At both sites, the fall herbicide treatment had killed much of the coastal bermudagrass. However, this enabled cool-season weeds, which germinate in the late fall and spring, and had not been present when the glyphosate was sprayed, to overtake these plots. They competed with the watermelon for light, water, nutrients, and may have even interfered with bee pollination, resulting in low total weights, and mean fruit weight and extremely high cull rates (Tables 2 and 3).
The hay mulch at SREC did a better job of controlling weeds than did the fall herbicide, and gave results that were generally similar to both herbicide treatments. Hay yields were low due to the dry season, resulting in estimates of only 960 lbs/A of hay for one cutting. However, prices were higher so a price of $40 per 1500 lb. round bale was used. This resulted in a potential hay income of $25.50/A for this season. (This hay was not fertilized or irrigated). Hay averaged 1 and 3.6% available protein and 59 and 54% total digestible nutrients on a dry matter basis, at SREC and COM, respectively. The higher protein at COM may have been due to previous fertilization at that site. However, it is possible that fall rains, after the test was terminated, could have provided another cutting of hay, effectively doubling production.
Before planting we sent a composite sample of the soil from the SREC site to the Soil Foodweb, Corvallis, OR for testing for microorganism populations. Fungal and bacterial populations were just high enough to be within the “acceptable” range. However, the fungal population was higher than samples from two other experimental fields at SREC. More testing should be done with this system to look at the potential for increasing these beneficial populations by using a system such as this strip cropping.
Educational & Outreach Activities
Participation Summary:
Roberts, W., N. Roe, J. Duthie, J. Edelson, J. Shrefler, G Cornforth, J Enis, and S. Smith. 1997. Integrating Watermelon and Forage Crops. HortScience. 32(3):539.
Roberts, W., J. Edelson, J. Duthie, J. Shrefler, J. Enis, S. Smith, W. O'Hern, N. Roe, G. Cornforth, T. Matthews. 1998. Multi-Cropping Cattle and Watermelon in the Southern Plains. Proc. 17th Ann. Hort. Ind. Show. Pp. 291-295.
On-farm demonstrations were conducted two years. Plots in Comanche county, Texas, and Atoka county, Oklahoma were used for this demonstration. A field day tour of the plots in Texas was attended by about 40 growers and industry reps. An abstract of this report will be added to the Texas Sustainable Agriculture website. Information was presented to a national audience at the American Society for Horticultural Science annual meeting. It was also presented to a regional audience at the Oklahoma-Arkansas Horticultural Industries Show. The topic was also presented on two occasions to a television audience via the KTEN Farm and Ranch Show.
This study was a two-state project, with projects being conducted in both Oklahoma and Texas. Both research and extension efforts were conducted by personnel from Oklahoma State University and Texas A & M. Farmers were part of the project in both states, and cooperated in on-farm research - demonstrations in 1997 and 1998.
Project Outcomes
The information gained from this study has indicated that watermelons can be grown in bermudagrass strips. The nature of bermudagrass is such that the grass will rapidly encroach upon the tilled strips, and without rigorous control practices, will overcome the watermelon plants in such a way that no yield will be obtained. This has been shown by the near zero yields that were obtained each year from the control plots where no weed control was attempted. While some broadleaf weeds were present in the plots, the major competitor with the watermelon plants was the bermudagrass.
It appears that weed control will be the limitation to producing watermelons in this manner, and two mechanisms have been shown to be acceptable for obtaining weed control. Plastic mulches will maintain weed control, but installation and particularly removal of the plastic are cumbersome, labor intensive, and ecologically questionable. Further development in the area of biodegradable mulches may offer further options in this area. The degradable mulches tested so far in this study were not considered satisfactory. Cultivation in combination with contact herbicides such as Poast have also been shown to be satisfactory, with yields being similar to what a farmer might obtain with a bare soil, clean cultivation field.
Other conclusions from this study are that the system is ecologically superior to clean cultivated fields. The low amount of bare soil present at harvest time is an indicator that soil erosion would be minimized with this production system. Similarly, the amount of soil covered by bermudagrass is a good indication that grass or hay can be produced on the same plots next spring. The hay that was baled from each field during the second and third year of the study has confirmed that both watermelons and hay can be harvested from the same field during a given year, and that the cycle can be repeated during each successive year.
The information gathered indicates that it will be possible for watermelon producers to grow melons in a field that has been, and still is, in bermudagrass. The bermudagrass will not need to be eradicated from the field. In fact, one cutting of hay can be obtained before the watermelons are planted. Alternatively, the field could be grazed for approximately two months before the watermelons are planted, and could then be grazed after the melons are harvested. This system gives farmers and ranchers another management tool that will allow farm diversity, increase farm profits, and lessen soil erosion.
Economic Analysis
Most of the market in this area demands watermelon in the 20-24 lb. size range. Therefore, few that we produced would be marketable through conventional commercial marketing channels. However, smaller melons are acceptable in some markets, so we have calculated the profits based on this assumption.
Watermelon costs and income were based on Cross Timbers budgets (Cornforth and Roe, 1996). If beds are spaced 30' apart, this results in 1452' of bed per acre. Economic analysis was based on a mean fruit price of $.04. Harvest cost used was $.01/lb. Standard polyethylene mulch costs about $0.027 per foot, and degradable costs about $0.028 per foot. Since most budgets are based on bed spacings of 6-12', this one is difficult to figure. We used a custom farming rate of $10 per acre for all operations. Although the beds do not cover an acre, the tractor does have to cover the whole acre as it would if there were more beds. A cost of $3 per acre for herbicide was used. Mulch hay was assumed to be old, low quality hay with no cost. It can be applied with side discharge mulching equipment.
All costs are per acre. The costs and incomes given in Tables 4 and 5 represent only differences between these treatments, not total costs. Although there may be some slight differences (transplanting may take longer or be more difficult in some mulches), initial costs (pre-plant tillage, fertilizer, drip tubing, transplants, planting costs, interest) for all were assumed to be equal. These totaled $197.55. Fixed costs from our budget could be assumed to be $193.83. Under commercial cultivation, only those fruit which appeared to be of marketable size and shape would be harvested, so the “undamaged” total weight per acre was used in these calculations. If these total costs ($391.38) are added to the additional cultural costs and harvest costs in Tables 4 and 5, none of the treatments would be profitable.
Areas needing additional study
Baker, J. D. 1977. Windbreaks [for fruit and vegetable crops] from barner grass. Agric. Gaz. N. S. W. 88(3):18-19.
Baxter, P. 1970. Orchard soil management trials. 1. effect of a weed-free or straw mulched strip on the growth and yield of young fruit trees. Australian J. Exp. Agr. Anim. Husb. 10(45):467-473.
Chandler, J. V., E. Boneta, F. Abruna, and J. Figarella. 1969. Effects of clean and strip cultivation, and of mulching with grass, coffee pulp, and black plastic, on yields of intensively managed coffee in Puerto Rico. J. Agr. Univ. P. R. 53(2):124-131.
Cornforth, G. C. and N.E. Roe. 1996. Irrigated watermelon budget- Texas Cross Timbers.
Dadson, R. B., and K. B. Boakye-Boateng. 1975. The influence of grass mulch on emergence, growth, and yield of soybeans, Glycine max L. merrill. INTSOY Ser. Int. Soybean Program, 6:69-76.
Elkins, D. M., J. W. Vandeventer, and G. Kapusta. 1977. No-till corn in living grass. Crops-Soils. 29(8):14-15.
Elkins, D., M. Anderson, G. Birchett, and G. Kapusta. 1978. No-till corn production in chemically-suppressed grass sod [by herbicides]. Agricultural. Rev. South Ill. Univ. School Agric. p. 76-79.
Folwell, R. J., D. L. Fagerlie, G. Tamake, A. G. Ogg, R. Comes, and J. L. Baritelle. 1981. Economic evaluation of selected cultural methods for suppressing the green peach aphid as a vector of virus diseases of potatoes and sugarbeets Myzus persicae. Bull. Wash. State. Univ. Coll. Agric. Res. Cent. Pullman, Wash., The Center. 1981. (0900) 15 p.
Hoyt, G. D., D. W. Monks, and T. J. Monaco. 1994. Conservation tillage for vegetable production. HortTechnology. 1994. 4(2)129-135.
Huslig, S. M., M. W. Smith, and G. H. Brusewitz. 1993. Irrigation schedules and annual ryegrass as a ground cover to conserve water and control peach tree growth. HortScience. 28(9):908-913.
Loy, S. J. W., L. C. Peirce, G. O. Estes, and O. S. Wells. 1987. Productivity in a strip tillage vegetable production system. HortScience. 22(3)415-417.
Nelson, W. A., B. A. Kahn, and B.W. Roberts. 1991. Screening Cover Crops for Use in Conservation Tillage Systems for Vegetables Following Spring Plowing. HortScience. 26(7):860-862.
Newenhouse, A. C. and M. N. Dana. 1989. Grass living mulch for strawberries. J. Am. Soc. Hort. Sci. 114(6)859-862.
Roberts, W., and B. Cartwright. 1991a. Vegetable Production with Conservation Tillage, Cover Crops, and Raised Beds. p. 72-76 In: T.C. Keisling (ed.). Proc. 1991 Southern Conservation Tillage Conf. Ark. Agric. Exp. Sta. Spec. Rep. 148.
Roberts, B.W. and B. Cartwright. 1991b. Cover Crop, Nitrogen, and Insect Interactions. p 164-165. In: W.L. Hargrove (ed.). Cover Crops for Clean Water. Inter. Conf., Soil & Water Cons. Soc., Ankeny, Iowa.
Roberts, B. W. and B. Cartwright. 1991c. Alternative Soil and Pest Management Practices for Sustainable Production of Fresh-Market Cabbage. J. Sust. Agric. 1(3):21-35.