Evapotranspiration and Yield Comparisons among Soil‐Water‐Balance and Climate‐Based Equations for Irrigation Scheduling of Sweet Corn¹

Abstract

As water for crop production becomes limited and costs of water increase there is a need for more accurate irrigation scheduling. Irrigation scheduling can be improved with reliable and rapid estimates of crop evapotranspiration (ET). The use of three climatebased equations and the soil‐water‐balance equation for estimating sweet corn (Zea mays L. ‘Jubilee’) ET for irrigation scheduling were compared in a 2‐yr field study on a mixed, mesic Cumulic Ultic Hapoxeroll soil. The three climate‐data‐based equations used were the Food and Agriculture Organization of the United Nations (FAO) modified Penman and the FAO and Soil Conservation Service (SCS) Blaney‐Criddle equations. Five irrigation levels ranging from 0 to 100%, with the 100% level intended to refill the root zone to field capacity, were all proportionately irrigated when approximately 50% of the available water was depleted in the 100% level as measured with a neutron meter. A sixth treatment in this randomized complete block experiment was irrigated with the amount of water equivalent to the crop ET estimated by the FAO modified Penman (M PEN) equation, when the crop ET had accumulated to 50% of the available soil water. The crop ET estimated by the soil‐water‐balance equation in 1984 was 481 and 447 mm for the 100% level and for plots irrigated according to the M PEN equation, respectively. In 1985 these ET estimates were 506 and 488 mm, respectively. The crop ET in 1984 was 404, 372, and 374 mm as estimated by the M PEN, FAO, and SCS Blaney‐Criddle equations, while in 1985 these equations estimated 450,448, and 379 mm, respectively. Yield differences were not significant between plots irrigated according to the M PEN equation and the irrigation levels of 50% or more in both years. Calculations indicated that the lower estimates of ET by the FAO and SCS Blaney‐Criddle equations, if used to schedule irrigations, would not be expected to cause yield decreases.

Comparison of yield components and quality factors of sweet corn under different irrigation scheduling strategies

“…Considering dry matter production of tender grains, the HI ranged, although not significantly, from 19.08% (T 4 ) to 28.58% (T 2 ), as shown in Table 3. These values are very similar to those obtained by Braunworth and Mack (1987a) and de Juan et al (1999).…”

“…These results were similar to those reported by Petersen et al (1985), where AW ranging from 410 to 500 mm, resulted in about 20 t ha À1 of good husked ear yield; and Braunworth and Mack (1987b), where nearmaximum yields (about 21 t ha À1 of good husked ears) were obtained from 311 to 604 mm of AW. Maximum yields (21 t ha À1 of good husked ears) were acquired by Braunworth and Mack (1987a) (2.262407829-0.005217702X+0.000028654X 2 -3.19028•10 -8 X 3 ) Figure 1. Adjustment models between yield (t ha À1 ) of commercial ears, with (a) and without (b) husk, tender grain (c) and total above-ground dry matter (d), and the seasonal volume of irrigation water (mm) applied to sweet corn.…”

“…Irrigation scheduling offers a means of supplying water in a timely manner. This way, stress can be alleviated so yield goals can be achieved, and water costs can be minimized by limiting deep percolation (Braunworth and Mack, 1987a). Irrigation scheduling is defined as the process of determining when to irrigate and how much water to apply.…”

“…Water balance or checkbook methods of irrigation scheduling for grain corn and other crops were presented by Martín de Santa Olalla et al (1994a, 1994b) and Martín de Santa Olalla and de Juan (1993) for application in Albacete, Spain. Braunworth and Mack (1987a) and de Juan et al (1999) illustrated water balance-based irrigation scheduling techniques for sweet corn; each one proposing different values of soil moisture depletion at which irrigation should be scheduled. Mubeen et al (2016) studied the application of CSM-CERES-Maize model for optimizing irrigated conditions and showed this model was useful in providing information to support decision-making regarding diverse irrigation regimes at the farm level in a semi-arid environment.…”

ANKARA KO$ULLARINDA MISIR SU TÜKETIMİNİN TAHMİNİNDE KULLANILABiLE.CEK YÖNTEMLER

“…Bu yöntemlerden tek ba şına hiç birinin bütün iklim bölgelerinde yeterli sonuç vermedi ğini yapılan çalışmalar ortaya koymu ştur (Jensen1973). Braunworth ve Mack (1987), tarla denemeleri ile belirledikleri mısır bitki su tüketimi değerini iklim verilerinden yararlanalarak Penman (FAO) ve BlaneyCriddle (SCS) yöntemleri ile hesaplad ıklan bitki su tüketimi değerleri ile karşılaştımnşlardır. Sonuçta Blaney-Criddle (FAO) ve Blaney -Criddle (SCS) yöntemlerini kullanarak elde edilen bitki su tüketimi değerlerinin gerçek bitki su tüketimi de ğerinden daha düşük olduğunu görmüşler ve bu iki yöntemi esas alarak yapılacak sulama programlarının mısır veriminde beklenmeyen verim azalmalar ına yol açacağı fikrine ulaşnuşlardır.…”