Discussion of “Using Thermal Units for Crop Coefficient Estimation and Irrigation Scheduling Improves Yield and Water Productivity of Corn ( Zea mays L.)” by C. Bautista-Capetillo, M. Zavala, and A. Martínez-Cob

2014 ◽  
Vol 140 (4) ◽  
pp. 07014007 ◽  
Author(s):  
Gürol Yıldırım
Keyword(s):  
Zea Mays ◽  
Zea Mays L ◽  
Water Productivity ◽  
Crop Coefficient ◽  
Irrigation Scheduling ◽  
Coefficient Estimation

scholarly journals THE WATER RELATIONS AND IRRIGATION REQUIREMENTS OF SUGAR CANE (SACCHARUM OFFICINARUM): A REVIEW

2011 ◽  
Vol 47 (1) ◽  
pp. 1-25 ◽  
Author(s):  
M. K. V. CARR ◽  
J. W. KNOX
Keyword(s):  
Water Stress ◽  
Water Relations ◽  
Sugar Cane ◽  
Root Zone ◽  
Water Productivity ◽  
Crop Coefficient ◽  
Saccharum Officinarum ◽  
Irrigation Scheduling ◽  
Background Information ◽  
Technology Choice

SUMMARYThe results of research on the water relations and irrigation needs of sugar cane are collated and summarized in an attempt to link fundamental studies on crop physiology to irrigation practices. Background information on the centres of production of sugar cane is followed by reviews of (1) crop development, including roots; (2) plant water relations; (3) crop water requirements; (4) water productivity; (5) irrigation systems and (6) irrigation scheduling. The majority of the recent research published in the international literature has been conducted in Australia and southern Africa. Leaf/stem extension is a more sensitive indicator of the onset of water stress than stomatal conductance or photosynthesis. Possible mechanisms by which cultivars differ in their responses to drought have been described. Roots extend in depth at rates of 5–18 mm d−1 reaching maximum depths of > 4 m in ca. 300 d providing there are no physical restrictions. The Penman-Monteith equation and the USWB Class A pan both give good estimates of reference crop evapotranspiration (ETo). The corresponding values for the crop coefficient (Kc) are 0.4 (initial stage), 1.25 (peak season) and 0.75 (drying off phase). On an annual basis, the total water-use (ETc) is in the range 1100–1800 mm, with peak daily rates of 6–15 mm d−1. There is a linear relationship between cane/sucrose yields and actual evapotranspiration (ETc) over the season, with slopes of about 100 (cane) and 13 (sugar) kg (ha mm)−1 (but variable). Water stress during tillering need not result in a loss in yield because of compensatory growth on re-watering. Water can be withheld prior to harvest for periods of time up to the equivalent of twice the depth of available water in the root zone. As alternatives to traditional furrow irrigation, drag-line sprinklers and centre pivots have several advantages, such as allowing the application of small quantities of water at frequent intervals. Drip irrigation should only be contemplated when there are well-organized management systems in place. Methods for scheduling irrigation are summarized and the reasons for their limited uptake considered. In conclusion, the ‘drivers for change’, including the need for improved environmental protection, influencing technology choice if irrigated sugar cane production is to be sustainable are summarized.

Optimizing Irrigation Scheduling of Summer Corn (Zea mays l.) in a Coastal Saline Field, China

2014 ◽  
Vol 1030-1032 ◽  
pp. 673-678
Author(s):  
Ting Ting Chang ◽  
Xiao Hou Shao ◽  
Wei Li ◽  
Xin Yu Mao ◽  
Wei Na Wang
Keyword(s):  
Zea Mays ◽  
Water Supply ◽  
Field Study ◽  
Irrigation Water ◽  
Water Productivity ◽  
Irrigation Scheduling ◽  
Corn Yield ◽  
Total Water ◽  
Irrigation Water Productivity ◽  
Local Farmers

Field study was conducted to determine the optimum irrigation quantity and times of corn in 2010. Different irrigation treatments were set according to local farmers’ practices. Irrigation amounts of T1, T2, T3, T4, T5 and T6 were 225, 270, 337.5, 300, 360 and 450 mm, respectively. Irrigation times of T1, T2 and T3 were 3, and T4, T5 and T6 were 4. The results showed that soil salt decreased with the increasing of irrigation water amounts. The corn yield varied from 6560 to 8060 kg/ha2. The highest yield was obtained from T5. Aiming to get high corn yield, total water supply of corn crops was 865 mm. Irrigation water productivity (Wpi) was the highest (2.92 kg/m3) with T1, and the lowest (1.74 kg/m3) with T6.

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