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adjust irrigation in response to increasing plant size ( Owen et al., 2008 ). However, these methods do not adjust to day-to-day changes in weather. To more effectively reduce water use without reducing plant quality, the relationship between plant growth

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-through method described by Wright (1986) using a benchtop pH and EC meter (Orion Dual Star; Thermo Fisher Scientific, Waltham, MA). Plants were fertilized at transplant and at each subsequent irrigation event using a 17N–2.2P–14.1K–4.0Ca–1.0Mg commercial water

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be obtained with 200–N and a leaching fraction of ≈10%. Conclusions This study presents positive outcomes for the prospective use of pecan wood chips in greenhouse substrates. Before the potential becomes reality, adjustments to water and fertilizer

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, 24 uniform dwarfs and 24 normal sibs were repotted into 15-cm standard pots filled with ProMix and placed in a growth chamber adjusted to noninducing conditions (28 ºC day and 25 ºC night temperature with a 18-h photoperiod). Plants were watered and

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191 WORKSHOP 23 (Abstr. 1059-1061) Methods and Techniques for Testing Chemicals Used for Thinning Fruit Crops

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Abstract

Experiments on the design of plot applicators for use in irrigation research were conducted, with 4 units constructed and successfully used on the University of Minnesota Sand Plain Experimental Field, of such applicators permits uniform application and precise measurement of the water applied. With minor adjustments, plot application areas up to 1, 250 ft2 (25 × 50 ft) can be accommodated.

Those units where the sprinkler arm was driven hydraulically by the available water pressure had less down-time and were more easily maintained, as compared to those which were driven by chain from a small gasoline engine. With hydraulically driven models, operating at pressures of 30 psi or less, it is recommended that cylinder diam of 1½-inch (or larger) be used.

Balloon-type tires are recommended for greater maneuverability between plots. The supporting beam of the applicator should be at the minimum heights permissible, as determined by the maximum anticipated height of the crop being grown.

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as either water use per seedling (g/seedling) or as height-adjusted water use (g/cm seedling height). On 24 June, cuttings were taken from the each seedling by severing the shoot within 0.5 cm of the substrate surface. One to five cuttings per

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Lettuce was produced using a new concept of hydroponics. The system is based on maintaining a constant water table (CWT). Plants grew on a flat surface and obtained the nutrient solution from capillary matting. One end of the mat was suspended in a trough containing the nutrient solution. The distance between the nutrient solution in the trough and the bench top was kept constant with a water level controller. The nutrient solution was resupplied from a larger reservoir. A ground cover on top of the capillary mat provided nutrient movement to the roots but prevented root penetration. Lettuce seedlings, germinated in small plug trays, were placed in holes cut in a 2.5-cm-thick styrofoam sheet. The styrofoam provided seedling support as well as protected the roots. Roots grew on the surface of the ground cover and were easily removed at harvest. The CWT could be adjusted by changing the height of the water level controller. The CWT concept of hydroponic production does not require pumps nor large storage reservoirs. No runoff occurs; the only nutrient solution used is that required by plants and a minimum amount of evaporation from the ground cover surface. Disease potential should be less than in other systems.

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A computer model was used to predict irrigation rates and numbers of emitters or microsprayers required to trickle irrigate Redskin/Nemaguard peach trees. Irrigation rates were 0, 50%, and 100% of the predicted requirement based on a crop coefficient of 50, 80, 100, 80, and 50 percent of pan evaporation for the tree's canopy area for May, June, July, August and Sept. respectively. Full irrigation (100% of predicted) was applied through 6, 8L/hr emitters or one 48L/hr microsprayer. Half the predicted rate was applied through 6, 4L/hr emitters or 1 24L/hr microsprayer. Control trees received no supplemental irrigation. Microsprayers height was adjusted to wet a surface area comparable to the 6 emitters. There was no significant difference in fruit size or yield based on emitter vs microsprayers, but fruit size and total yield was increased in direct proportion to irrigation rate. There was no treatment effect on tree pruning weights. Moisture measurements indicated that trees de-watered the soil efficiently enough that water never moved below the 30 cm level in spite of the fact that up to 260 liters per tree per day were applied in mid-summer.

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of plants has different K p values, and overall water use of each landscape depends on both K p and percent area of each hydrozone. Area of each hydrozone was incorporated, thus obtaining adjusted K p for woody plants, turf, and perennials: and K l

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