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  • Author or Editor: G. R. Hanson x
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Garlic (cv California Late) was produced under four irrigation regimes (110% and 130% evapotranspiration with two water cut-off dates, 10 and 24 May 1999) in combination with three nitrogen fertilization levels (100, 250, and 400 lb total N). Bulbs were manually harvested mid-June, cured 3 weeks shaded at ambient temperatures and the outer whorl of cloves manually peeled. Samples were freeze-dried, and carbohydrate (fructan and free sugars) and alliin (substrate for alliinase activity and indicator of potential pungency) concentrations were determined by HPLC. The percent dry weight was not affected by the irrigation treatment, but was reduced with increased N rate (41.3% to 39.0%). Alliin concentrations varied from 8.3 to 13.8 mg/g DW for 110% and 130% Eto irrigation treatments. Alliin concentrations were not affected by N fertilization (average = 11.5 mg/g DW). Fructan concentrations were affected by N fertilization treatment, with the highest content (802 mg/g DW) associated with the lowest N level, and the lowest (717 mg/g DW) content in samples from the highest N rate. Sucrose concentrations increased with increased N, but glucose and fructose concentrations did not vary with N fertilization. Fructan as percent of total carbohydrate remained constant across irrigation treatments (96.6% + 0.2%) and across N fertilization treatments (96.6% + 0.3%).

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Abstract

Mature ‘Red Delicious’ apple trees (Malus pumila Mill) were sprinkled intermittently with an overhead irrigation system after completion of winter rest. A 2-minute sprinkling cycle operated automatically whenever the ambient air temperature of the orchard exceeded 7°C until the control trees reached full bloom. Evaporative cooling of the treated trees reduced bud temperatures to within 2°C of the wet bulb temperature. Treated trees reached full bloom 17 days after the untreated controls.

Open Access

Raised bed production trials were conducted to evaluate the effectiveness of effluent from a biofloc-style recirculating aquaculture system producing nile tilapia (Oreochromis niloticus) as nutrient-rich irrigation water for fall ‘Celebrity’ tomato (Solanum lycopersicum) production. The objective of this study was to provide baseline vegetable production data and justification for using aquaculture effluent as a water and nutrient resource. The experiment was a split-plot, randomized block design with three treatments: aquaculture effluent, granular fertilizer, and fertigation. Tomato seeds were sown in June, transplanted in August, and grown until Oct. 2019 in nine replicated raised beds. Conventional field tomato production practices were followed throughout the trial, and data were collected for tomato fruit yield, market quality, size, leaf greenness (SPAD), and foliar nutrient analysis. Fruit yield was similar between fertigated and aquaculture effluent treatments, with granular fertilizer resulting in yield that was significantly lower (P ≤ 0.033). SPAD measurements were similar among treatments. All nutrients met or exceeded sufficiency ranges. Foliar nutrient analysis revealed no significant difference for nitrogen, phosphorus, potassium, magnesium, calcium, boron, zinc, manganese, and iron among treatments. Sulfur and copper levels were significantly lower (P < 0.05) with aquaculture effluent treatment as compared with the granular and fertigated treatments. Overall, tomato production using aquaculture effluent as a water and nutrient supplement produced similar yields to commercial practices, making it potentially viable for producers.

Open Access

Like everything for the past 2 centuries, agriculture has depended increasingly on fossil fuel energy. Pressures to shift to renewable energy and changes in the fossil fuel industry are set to massively alter the energy landscape over the next 30 years. Two near-certainties are increased overall prices and/or decreased stability of energy supplies. The impacts of these upheavals on specialty crop production and consumption are unknowable in detail but the grand lines of what will likely change can be foreseen. This foresight can guide the research, extension, and teaching needed to successfully navigate a future very unlike the recent past. Major variables that will influence outcomes include energy use in fertilizer manufacture, in farm operations, and in haulage to centers of consumption. Taking six increasingly popular fruit and vegetable crops and the top two horticultural production states as examples, here we use simple proxies for the energy requirements (in gigajoules per ton of produce) of fertilizer, farm operations, and truck transport from Florida or California to New York to compare the relative sizes of these requirements. Trucking from California is the largest energy requirement in all cases, and three times larger than from Florida. As these energy requirements themselves are all fairly fixed, but in future will likely rise in price and/or be subject to interruptions and shortages, this pilot study points to two commonsense inferences: First, that fruit and vegetable production and consumption are set to reposition to more local/regional and seasonal patterns due to increasing expenses associated with fuel, and second, that coast-to-coast produce shipment by truck will become increasingly expensive and difficult.

Open Access