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Richard C. Beeson Jr.

seasons to reach marketable size. Each species required a unique equation. In 2004, a new model to calculate a crop coefficient, termed water needs index (WNI), was proposed ( Beeson, 2004 ). The term was invented because nursery production and landscapes

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Stefano Poni, Alberto Palliotti, and Fabio Bernizzoni

and to David Verzoni and Carol Brannigan for language revision. We also acknowledge Cesare Intrieri (Univ. of Bologna, Italy) for lending the CIRAS-2 apparatus and Alessandro Rossi (Isee Systems software) for helping with the model.

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Doyle A. Smittle, W. Lamar Dickens, and M. Jane Hayes

An irrigation scheduling model for summer squash (Cucurbita pepo L.) was developed and validated during 1986, 1987, and 1989. The model is represented by the equation: 12.7(i - 4) × 0.5ASW = Di-1 + [E(0.14 + 0.015) - P - I]i, where crop age in days is i; effective root depth is 12.7(i - 4) with a maximum of 381 mm; usable water (cubic millimeter per cubic millimeter of soil) is 0.5ASW, deficit on the previous day is Di-1; evapotranspiration is pan evaporation (E) times 0.14 + 0.015i; rainfall (in millimeters) is P; and irrigation (in millimeters) is I. The model was validated during the three years using a line-source irrigation system with irrigation depths ranging from 5% to 160% of the model rates. Nitrogen rates were 50%, 100%, and 150% of the recommended rate. Marketable fruit yields increased as the irrigation depths increased up to the model rate then decreased with greater water application depths. Marketable fruit yields increased as the N rate increased in 1987 and 1989, but yields were similar at all N rates in 1986. The shelf life of marketable fruits was not influenced by irrigation or N rates.

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Catherine M. Grieve, James A. Poss, Peter J. Shouse, and Christy T. Carter

developmental timing, ion relations, growth, and quality of a commercially important cut flower. A modeling approach based on stem length development as a function of thermal time provides future growers and researchers a potentially useful tool to estimate

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Omar A. Lopez, Danny L. Barney, Bahman Shafii, and William J. Price

light. Therefore, the objectives in conducting this research were to develop a regression model of the germination process for red huckleberry seeds and to use the regression model to assess the effects of temperature and GA concentration on cumulative

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Yuliya A. Salanenka and Alan G. Taylor

permeability ( Salanenka and Taylor, 2008 ). The number of tracers was expanded for this study and included 10 model compounds to represent a diverse array of chemical structures and giving special attention to the value of log K ow , charge, molecular weight

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Xuewen Gong, Shunsheng Wang, Cundong Xu, Hao Zhang, and Jiankun Ge

for determining a scientific and rational irrigation schedule to improve water use efficiency ( Qiu et al., 2017 , 2019 ; Yan et al., 2017 ; Yuan et al., 2001 ). Establishing an ET c model is a simple method to get water requirements of crops, thus

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Eric Simonne and Doyle A. Smittle

An irrigation scheduling model for turnip greens (Brassica rapa L.) was developed and validated.. The irrigation scheduling model is represented by the equation: 12.7 (i-3) * 0.5 ASW = 0i-1 + Ei(0.365+0.00154i+0.00011i2) - R - I where crop age is i; effective root depth is 12.7 * (i-3) with a maximum of 300 mm; usable water (cm/cm of soil) is 0.5 ASW; deficit on the previous day is Di-1 evapotranspiration; is pan evaporation (Ei) times 0.365+0.0154i+0.00011i2; rainfall (R) and irrigation (I) are in millimeters. Yield measured as leaf weight, and quality analyzed in terms of color (Gardner XL20 cronameter L, a, b), leaf blade and blade: stem weight ratio were determined. Leaf yield and quality responses were affected by both irrigation and fertilizer rates. Yield increased quadratically as irrigation rates increased from 0 to 190% of the model rate. Maximum leaf yields were produced by irrigations at 100% of the model rate. Leaf quality parameters also tended to change quadratically with irrigation rates. Leaf yield and quality changed quadratically as nitrogen fertilizer rates increased from 80 to 120% of the median recommended N rate for Georgia.

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Xiaofeng Yang, Lianzhu Chen, Ming Cao, Xuebin Zhang, and Shaopeng Li

protective cultivation in Hainan, and its cultivation techniques are being increasingly improved. There is no doubt that fertilization management is still the key to improve its yield and quality. Fully developing nitrogen and potassium coupling model is

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Roland Ebel

small organic farms are implementing the chinampa model. For example, in the Mexican state of Guanajuato, a farm produces maize and legumes in a traditional chinampa enriched with permaculture crop management ( Laado, 2013 ). Chinampa-like production