Marci Spaw and Kimberly A. Williams
This decision case presents the issues a grower would face when deciding where to place and how to orient a high tunnel structure on a specific farm site. It provides a tool to teach site planning concepts on a small scale that are easily transferable to issues addressed when planning for construction of all sizes and types of protected-environment structures. In this case, the owner of Full Moon Farm must decide the placement of her high tunnels on a given farm site. Factors to consider include wind, snow, and ice loads as well as structural integrity, labor efficiency, and optimizing light levels. Ultimately, no one solution meets all recommended criteria, so the grower must prioritize the importance of various factors to come to a decision. This case study is intended for use in upper-level undergraduate horticulture courses, and although the principles are broadly applicable to site planning across geographic regions, it is most appropriate for climates above lat. 35°N. In particular, it may prove useful in courses such as greenhouse management and production courses for vegetables, cut flowers, and small fruits, where students assume the role of grower/farmer in the site planning process. This case study is supported by a website version with digital images, digital video, and maps that can be used both inside and outside of the classroom; all are downloadable from the website http://www.hightunnels.org/planningcasestudy.htm. The teaching notes present an unorthodox solution to the Full Moon Farm site planning dilemma.
held at the 87th ASHS Annual Meeting Tucson, Arizona Moderator: Thomas H. Yeager 8 Nov. 1990
S. Al-Ghawas and K. Al-Mazeedi
Treated wastewater will play important role in the implementation of Kuwait National Agriculture Development Plan. As a substitute for brackish or fresh water in irrigation, treated municipal wastewater can be a practical solution. Nevertheless, special health and environmental considerations should be carefully assessed when using this water source. These considerations include potential infection with human pathogens, effects of heavy metals on the public health, and the ecological consequence on soil and water resources at large. These topics were investigated under controlled environment using a range of crops and two types of irrigation water: a tertiary treated wastewater source and fresh tap water as a control. Soil, water, and plant samples were collected at fixed intervals and were analyzed for total viable count; total Coliforms; faecal Coliforms; and faecal Streptococc, Salmonellae, Shigella, Ascaris imbricoides and pathogenic viruses. In addition, we measured for nine heavy metals (Cd, Zn, Fe, Mn, Cu, Ni, Co, Cr, and Pb). Soil salinity and build-up of sodicity in soil and ground water sources also were investigated for any changes that could indicate a potential long-term degradation effect. The results after 3 years of study indicate that the generated tertiary treated wastewater is of high quality. Its potential pathogenic content is below the guidelines recommended by WHO for using wastewater in mixed agriculture, and therefore, it had no accumulative effect on the irrigated soil or the different parts of plant tissues that were analyzed. However, treated effluent have occasionally exhibited pathogenic index higher than permitted levels reflecting the fluctuating nature of wastewater treatment. Heavy metals content of irrigation water and from the irrigated soils were negligible, and the plant tissues that were analyzed contained metallic contents below the established range in IPE. The treated water had low TDS but high sodium content with 25–35 SAR values; however, the effect on the irrigated soil was insignificant due to the calcareous nature of the soil used. This study used drip irrigation system and under similar conditions no health problems will be expected when using tertiary treated wastewater for irrigation. To minimize potential risk to the consumers, specific guidelines are recommended on the type of crops to grow and the horticulture practices to be used.
P. Inglese, G. Barbera, T. La Mantia and S. Portolano
We established a cladode load and thinning time that maximized fruit and flesh size in `Gialla' cactus pear (Opuntia ficus-indica Mill.). Five weeks after spring flush removal, second flush flower buds were thinned to nine, six, or three per cladode; the same treatment was repeated during the early stages of fruit development. Control cladodes had a natural load of 15 fruit. Time of thinning did not affect fruit growth and ultimate weight. Fruit and flesh weight increased with thinning, but export weight was obtained only in cladodes with no more than six fruit. Heavier thinning did not result in any further increase of fruit or flesh weight. Percent flesh was not affected by thinning. Fruit characteristics, such as total soluble solids concentration and seed content did not change with thinning, but the seeds: flesh ratio decreased with thinning. Fruit on cladodes with the lowest load ripened earlier than those on more heavily yielding cladodes.
K.M. Batal, M.R. Hall, D.M. Granberry, J.T. Garrett, D.R. Decoteau, R.T. Dufault, G.D. Hoyt, T.C. Gilsanz, J.M. Davis and D.C. Sanders
A vegetable production system using winter cover crops and N rates was evaluated for several years in Georgia, South Carolina, and North Carolina. Snap bean, cucumber, tomato, potato, and sweetpotato crops were tested at different locations. Cover crop plots produced higher yields and better quality in all locations as seasons progressed over 4 years. Soil N levels in fallow, wheat, and clover plots were similar at initiation, but N gradually increased in clover plots in successive years. Yield and quality of root crops improved with Crimson clover without N applications compared to fallow plots with 60 kg N/ha. Effects on yield and tuber size are discussed. Nitrate and NH4-N in the soil profile from 15- to 150-cm depth were monitored at all locations. Nitrogen availability, depletion, and leaching below the root zone were determined. At low N rate, clover plots had slightly higher NO3 in the soil profile; however, at high N rate, N supply by clover was not as critical, and N leaching was detected at much lower depths than at low N rates.
Donna Coffindaffer-Ballard, B.C. Bearce, J. Skousen and G. Lambert
A 0.2-ha reclaimed minesoil site near Welch, W.Va., was amended with sewage sludge, hardwood bark, and a sorghum–sudan hybrid green manure crop to demonstrate production of horticultural crops. A selection of crops, including white birch, forsythia, zinnia, tomato, yarrow, red raspberry, and strawberry, was planted and grown. Plant growth and development, including flower and fruit production, tended to be enhanced by sludge-amended soils and reduced in green manure and hardwood bark–amended soils. Sludge increased pH, Ca, P, and Mg levels above that in the other treatments. Hardwood bark increased Mn but decreased P. The green manure amendment increased soil Fe content. In 1994 `Allstar' strawberry yield and berry weights were similar for all plots, but yield was about 10% of expected and was very close to the economic break-even point. Third-year yield of 1992 planted `Heritage' raspberries was about one-half the expected yield of 5000 lbs/acre, but still considered profitable. Zinnia flower production yielded a calculated 32% return on investment. Assuming that 50% forsythia plants were saleable in 2 years, return on investment was projected to be 30%. For white birch, assuming half were saleable in 4 years, a 16% return on investment was projected.