, tomato varieties, soil and irrigation types, with allowances for supplemental N applications ( Olson et al., 2011 ). Growers typically follow UF/IFAS irrigation recommendations, but use N fertilizer rates greater than the UF/IFAS recommendation
Luther C. Carson and Monica Ozores-Hampton
Kelly T. Morgan, T. Adair Wheaton, William S. Castle, and Laurence R. Parsons
–N concentrations in groundwater above the allowed maximum contaminant limit have been attributed to application of nitrogen (N) fertilizers for citrus production ( Alva et al., 2003 ). The N source, rate of uptake, irrigation management, duration and intensity of
Bee Ling Poh, Aparna Gazula, Eric H. Simonne, Robert C. Hochmuth, and Michael R. Alligood
irrigation management Acta Hort. 758 227 233 Levin, L. van Rooyen, P.C. van Rooyen, F.C. 1979 The effect of discharge rate and intermittent water application by point-source irrigation on the soil moisture distribution pattern Soil Sci. Soc. Amer. J. 43 8 16
Josiah W. Worthington, James L. Lasswell, and M.J. McFarland
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.
Steven B. Polter, Douglas Doohan, and Joseph C. Scheerens
staff of the Laboratory for Pest Control Application Technology.
Peter Purvis, Calvin Chong, and Glen Lumis
Plug-rooted liners of common ninebark [Physocarpus opulifolius (L.) Maxim.] were grown in 6-L nursery containers filled with 73% composted pine bark, 22% sphagnum peat moss, and 5% pea gravel (by volume). Plants were fertilized with Polyon (Nutryon) 17–5–12 (17N–2P–5K) 6-month controlled-release fertilizer at various rates (2.5, 4.5, 6.5, and 8.5 kg·m-3) pre-incorporated, topdressed, or dibbled (placed under the liner at potting). Plants were trickle-irrigated daily with low (0.4-L), middle (0.8-L), or high (2.0-L) volumes of water to maintain leaching fractions of <0.15, 0.25–0.35, or >0.60, respectively. Regression analysis indicated that growth of ninebark increased from 30 to 109 g/plant with increasing rates of incorporated fertilizer (mean over irrigation volumes), from 27 to 71 g/plant with topdress and from 59 to 103 g/plant with dibble. Electrical conductivity (EC, mean over five dates) of the leachate throughout the season was highest with dibble (0.85 dS·m-3), intermediate with incorporated (0.81 dS·m-3), and least with topdressed (0.76 dS·m-3). With low irrigation volumes, growth of ninebark increased from 42 to 81 g/plant with increasing rates of fertilizer (mean over methods), and from 39 to 105 g/plant with middle or high volumes (common regression curve). With low irrigation volumes, leachate EC increased from 0.74 to 0.94 dS·m-3 with increasing rates of fertilizer, and from 0.75 to 0.81 dS·m-3 with middle or high volumes.
Aaron L. Warsaw, R. Thomas Fernandez, Bert M. Cregg, and Jeffrey A. Andresen
experiment were to determine the effects of scheduling irrigation applications based on DWU on irrigation volume, plant growth, substrate soluble salt accumulation, runoff, and nutrient loss compared with a conventional irrigation rate. Materials and Methods
Ibukun T. Ayankojo, Kelly T. Morgan, Davie M. Kadyampakeni, and Guodong D. Liu
orders. Because of their sandy nature, these soil types have low water-holding capacities, low organic matter contents (within the root depth), and low nutrient retention capacities. Therefore, excessive irrigation and/or N application rates with intense
Reagan W. Hejl, Benjamin G. Wherley, James C. Thomas, and Richard H. White
One means of achieving water conservation in turf management is by providing water at rates below a plant’s maximal consumptive water use, otherwise known as deficit irrigation ( Feldhake et al., 1984 ; Fry and Butler, 1989 ; Qian and Engelke
Jeff B. Million and T.H. Yeager
-related inputs for each zone include percent plant cover, container diameter, container spacing, plant height and width, irrigation-capturing ability of plant, and irrigation application rate ( Fig. 1 ). Additional options for adjusting irrigation include