analysis for Lomatium grayi seed yield (y, kg·ha −1 ) in response to irrigation (x, mm/season) using the equation y = a + b· x + c· x 2 in 2007–15, and 9-year averages. For the quadratic equations, the amount of irrigation that resulted in maximum
, reaching 586.3 mg·kg −1 . The difference between the highest and the lowest was 1183 mg·kg −1 . Leaf Fe and Zn content as shown in Fig. 1B and C showed quadratic responses to foliar application levels, respectively, both reaching a plateau at 100 mL·L −1
yields of E. umbellatum had quadratic responses to irrigation amount in 2007–10 and 2012–16 ( Table 6 ; Figs. 1 – 3 ). The quadratic response to irrigation in 2010 was not statistically significant, and in 2011, the response to irrigation was linear
of the four-row plots. The seed was cleaned from stalks and chaff and weighed. Seed yield responses to irrigation were evaluated by linear and quadratic regression. Seed yield for each species each year was regressed separately against 1) applied
, quadratic, linear-plateau ( y = a + bx if x < critical rate, y = plateau if x > critical rate), and quadratic-plateau ( y = a + bx + cx 2 if x < critical rate, y = plateau if x > critical rate), where y was the response, x was P
224 kg·ha −1 N application rate. However, the slope coefficient of the quadratic model was larger for the late-season sampling date compared with early season, indicating a greater effect of each N rate at this later timing. Fig. 1. Response of
calibration methodology. The same procedure was not applicable for time domain dielectric sensor since its response was quadratic. Results and discussion Sensors calibration Frequency domain dielectric sensor. Our results indicated that the relationship
, shoot dry weight (SDW), and growth index (GI) of ornamental cabbage plants at the end of the experiment. Total leaf area (LA) and plant GI of ‘Glamour Red’ increased linearly and quadratically in response to an increase of the N concentration in the
weight ( A ) and phosphorus (P) uptake ( B ) by lettuce as a function of sources (SUP, superphosphate; and STR) and rates of P applied. Previous studies have reported a significant quadratic response of lettuce yield and P uptake to common P fertilizers
, NC) using a modified Newton Gauss iterative method. Based on these criteria, the linear model best described the MSRN response to soil moisture content, whereas quadratic functions best described both SRDR and time to 50% storage root development. The