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Xin Zhao, Qianqian Dong, Shubang Ni, Xiyong He, Hai Yue, Liang Tao, Yanli Nie, Caixian Tang, Fusuo Zhang and Jianbo Shen

( He et al., 2017 ). However, soil and nutrient management for macadamia production is still in its infancy. Many guide brochures on the Macadamia grower’s handbook have been used in Australia and America ( Bittenbender and Hirae, 1990 ; O’Hare et al

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Aaron Heinrich, Richard Smith and Michael Cahn

difference test ( P < 0.05). Linear regression analysis was performed using SigmaPlot (version 12.0; Systat Software, San Jose, CA). Results and discussion Nutrient uptake. Mean N, P, and K uptake over a range of soil and climatic conditions during the 2011

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Craig D. Stanley and Gurpal Toor

Any factor within a production system that inhibits, impairs, restricts, or reduces the availability of applied water or nutrients can certainly contribute to inefficient use of either of these inputs. It is essential to understand what these

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Youssef Rouphael, Giampaolo Raimondi, Rosanna Caputo and Stefania De Pascale

al., 2005 ). This makes necessary the discharge of the nutrient solution resulting in water and nutrient loss ( Massa et al., 2011 ), therefore the term “semiclosed” is used for such cultivation systems ( Carmassi et al., 2007 ). Several scientists

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Martin P.N. Gent

decrease in water stress and an increase in leaf conductance ( Baille et al., 2001 ). However, for tomato, leaf transpiration in response to sunlight was less under shade than in a greenhouse without shade ( Medrano et al., 2004 ). Nutrient uptake and use

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Martin P.N. Gent and Richard J. McAvoy

efficient than overhead watering ( Dole et al., 1994 ; Morvant et al., 2001 ) and also more efficient in terms of nutrient use ( Haley and Reed, 2004 ; Purvis et al., 2000 ; Zheng et al., 2004 ). The benefits of ebb and flow, as it is currently applied

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Luther C. Carson and Monica Ozores-Hampton

CRF nutrient release factors and CRF performance in each of the vegetable production systems using subsurface (“seepage”) irrigation will help optimize the use of CRF in Florida. Seepage irrigation consists of managing a water table perched above a

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Nicholas A. Pershey, Bert M. Cregg, Jeffrey A. Andresen and R. Thomas Fernandez

University Soil Testing Laboratory for NO 3 − -N and PO 4 3− -P analysis. The cadmium reduction method was used for NO 3 − -N analysis and the Bray and Kurtz P-1 Test for PO 4 3− -P analysis ( Frank et al., 1998 ). To determine net nutrient load, bulk

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Mohamed Benmoussa and Laurent Gauthier

In soilless culture, the buffering capacity of the root environment for nutrients is low. This, combined with fluctuations of climatic factors and changes in nutrient uptake rates, can lead to nutrient imbalances. In order to achieve high yield and better quality, it is necessary to keep the nutrient concentrations in the root environment at the target levels. This requires frequent analysis and adjustments to the nutrient solution. Currently, leaching of the growing media or renewal of the nutrient solution is commonly used to avoid accumulation or depletion of nutrient in the root environment. However, this practice lowers the efficiency of fertilizers and can lead to the contamination of the ground water. One way to remedy to this problem is through the use of nutrients uptake models to track the composition of the nutrient solutions. The objective of this study was to develop such models. Such models can be used to maintain balanced nutrient solutions for longer periods. This can lead to reduced leaching and improved fertilizer use efficiency. Macronutrient (N, P, K, Ca, and Mg) uptake models were developed for tomato plants grown in an NFT system using data collected from experiments conducted in the Laval Univ. greenhouses. Analysis of the experimental results showed that the main factors affecting nutrients uptakes are light and transpiration.

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A.L. Shober, C. Wiese, G.C. Denny, C.D. Stanley and B.K. Harbaugh

+ nitrite (NO 2 )–N [U.S. Environmental Protection Agency (USEPA), 1993a], NH 4 –N ( USEPA, 1993b ), and DRP ( Pote and Daniel, 2009 ) using a discrete analyzer (AQ2; Seal Analytical, Burgess Hill, UK). Nutrient loads from each pot (in milligrams) were