International Commission on Irrigation and Drainage
26
thEuro-mediterranean Regional Conference and Workshops
« Innovate to improve Irrigation performances »
12-15 October 2015, Montpellier, France
WORKSHOP:PRECISION IRRIGATION FOR SUSTAINABLE CROP PRODUCTION
THE IMPACT OF MANAGEMENT PRACTICE ON YIELD AND IRRIGATION WATER USE EFFICIENCY FOR PADDY RICE UNDER SHORTAGE ENVIRONMENT
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THE IMPACT OF MANAGEMENT PRACTICE ON YIELD AND IRRIGATION
WATER USE EFFICIENCY FOR PADDY RICE UNDER SHORTAGE
ENVIRONMENT
Yi-Ju Lin 1; Ching-Tien Chen 2*; Cheng-Haw Lee 3
ABSTRACT
In order to adapt the current water management practices to dramatic rainfall pattern in Taiwan, an experiment was conducted in the field to evaluate the effect of different water management practices on crop productivity. The result shows that, with the yield and water saving for irrigation are considered at the same time, it is recommended adjusting the cultivation time for the drought in spring, and planting on February 16th and irrigation interval of 7 days is recommendable for paddy rice during the heading stage, that amounts of water can be saved for about 27.3%, and the yield is only slightly influenced yield. In view of water saving efficiency, it reaches the best of 39.7% under the modify SRI; however the yield reduction rate is up to 7.2%~16.5%. On water resource productivity, The modify SRI method is the best to plant on January 16th, that amounts of water resource productivity is about 0.8 kg/m3.These suggestions can serve as the foundation for the irrigation bureau to implement a feasible irrigation ration policy and lead to the minimum water requirements under different drought conditions.
Keywords: Paddy rice ; Drought tolerance ; Saving irrigation ; BMP ; SRI
1 [PhD student], [Department of Resources Engineering, National Cheng Kung University], [No.1, University Rd., Tainan City 70101, Taiwan],
[pippolin@msn.com] ;
2 [Associate Professor], [Department of Civil and Water Resources Engineering, National Chiayi University], [No.300, Syuefu Rd., Chiayi City 60004, Taiwan],
[ctchen@mail.ncyu.edu.tw]*;
3 [Professor], [Department of Resources Engineering, National Cheng Kung University], [No.1, University Rd., Tainan City 70101, Taiwan],
WORKSHOP : PRECISION IRRIGATION FOR SUSTAINABLE CROP PRODUCTION
THE IMPACT OF MANAGEMENT PRACTICE ON YIELD AND IRRIGATION WATER USE EFFICIENCY FOR PADDY RICE UNDER SHORTAGE ENVIRONMENT
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1. Introduction
The restriction of terrain and the unequal distribution of rainfall have resulted in limited application of water resource in Taiwan, and the drought reaches its peak during November to April. Now, under the impact of global warming, the extreme weather had relatively elevated the frequency and intensity of drought to another level. Therefore, in expect of minimize the impact of extreme climate and water shortage in spring, the application of all irrigation managing strategies during the drought period would be a major task to all irrigation managers.
This research would apply rotation irrigation along with regional rainfall and crop’s growing characteristics to conduct field experiment. The field sets at the irrigation center in Chia-Nan Irrigation Association in Chia-Nan Plain, which is the main grain production and the most severe drought region in Taiwan. The experiment postpones the crop planting date from January 16th to February 16th during the first-season paddy rice of year 2014, and uses different water management practice including the best water management practice (BMP), the modify system of rice intensification (Modify SRI) and conducting rotation irrigation interval of 7 days during heading stage(MBMP). The result would be analyzed on the influence to the paddy rice yield, agronomic traits, crop water requirement, field irrigation water, and water resource productivity, further to evaluate the best management practice in the drought period, the most appropriate irrigation amount of water and water saving effectiveness of paddy rice without influence the yield. This research expects to distribute the irrigation water more flexibly and effectively in order to cope with climate change and the severe water shortage problem in spring.
2. Materials and methods
2.1 Materials
This materials is applied in the purpose of understanding how different water saving irrigation designs and treatments such as planting date, irrigation timing, irrigation water amount and irrigation interval of paddy rice could influence on the yield, drought tolerance and water resource productivity. The experiment rice variety would be Tainan No. 11, which is widely used in Taiwan with high yields. This research conducts field experiment at the experiment station of the irrigation center in Chia-Nan Irrigation Association (23°13' N, 120°11' E) where the altitude from about 4m and distant 10 km away from the coastline(Figure 1). The terrain of the station is plain that locates in the tropical region of Chia-Nan Plain.
The research targets on the first-season paddy rice that has severe and high rate of drought issue in Taiwan. Considering the characteristic of regional rainfall, physical properties of crop, rotation irrigation method and management practice, the field experiment was designed. By carrying out BMP and Modify SRI with single seedling or numerous seedlings (Barison, J., & Uphoff, N., 2011) and then postponing from January 16th (controlled) to February 16th, and conducting water saving rotation irrigation with
the interval 7 days during the heading stage (irrigates according to the general irrigation plan before rotation irrigation conducted) along with 5 types of irrigation design that random planted and ran in duplicate. The field experiment is divided into 10 blocks of size 19m×20m which is roughly 3,800 square meters.
Figure 1 Location of study area in Chia-Nan plain, Taiwan
2.2 Methods
By applying analysis of variance, drought tolerance analysis (yield reduction rate), water saving rate and water resource productivity analysis, this research could help to understand the influence of different irrigation operational and management strategies on yield and amount of irrigation water.
2.2.1
Analysis of Variance
This research took analysis of variance with randomized complete block designs in hope of learning the differences in various responses to management practice. In mathematical statistics, it is proved that when there is no difference in various averages (meaning no effect), the within-groups variation equals to between-groups variation. This research had made null hypothesis to the analysis of variation that the investigated agronomic traits have no significant difference under different management practice. The standard of significance is set as α=5%.All the agronomic traits have significant difference in different management practice and showed significant difference on a remarkable level of 5%.
WORKSHOP : PRECISION IRRIGATION FOR SUSTAINABLE CROP PRODUCTION THE IMPACT OF MANAGEMENT PRACTICE ON YIELD AND IRRIGATION WATER USE EFFICIENCY FOR PADDY RICE UNDER SHORTAGE
ENVIRONMENT
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2.2.2
Analysis of Impact on Crop Water Requirement of Paddy Rice
Crop water requirement is the essential amount of consumed water for growing crops, all irrigation strategies should be established under the purpose of applying and filling the required amount of evaporation while growing the crops. In order to understand the impact on crop water requirement by conducting management practice, this research adopts the most accurate Penman-Monteith Equation (Monteith, 1994) to calculate the reference crop water (ET0). The ET0 of Tainan area
could plus crop coefficient with various planting interval could further obtain the crop water requirement in different growth stages.
2.2.3
Analysis of Drought Tolerance and Water Saving Efficiency of Paddy Rice
The level of paddy rice’s drought tolerance (yield index) is defined with the perspective of yield reduction rate(%). The drought tolerance is better when the yield reduction rate is low and vice versa. In order to promote water saving irrigation among farmers and to apply it easily in the water shortage period, the efficiency of water saving irrigation set standard on the water use of general farmer’s operation (irrigation water in controlled area). This research defines under the perspective of water saving rate(%) that the higher the rate reaches, the better the irrigation water saving efficiency gets.
2.2.4
Water Resource Productivity Index
This research apply water resource productivity index to evaluate the effectiveness of irrigation based on different operations. The higher the water resource productivity index, the better the water resource utilization effectiveness. In other words, when water resource productivity rises, the yield in field irrigation water per hectare gets better.
3. Results and Discussions
3.1 Analysis of the Impact on Management Practice to Agronomic Traits
The different management practice of first crop in 2014 has significant influence on plant height, total tiller number per cluster, effective tiller number per cluster, spikelet number per spike, grain number per spike, spike weight per cluster, fertility and yield. The highest plant height is Modify SRI with single seedling(99.7cm). The greatest total tiller number per cluster and effective tiller number per cluster is Modify SRI with numerous seedlings(42 and 41). The most spikelet number per spike and grain number per spike is Modify SRI with single seedling(170.4 and 153.6). Then, the heaviest spike weight per cluster is BMP that planting date on February 16th(82.2g). The best performance of fertility is 99% by
conducting MBMP. The maximum yield is 7,920 kg/ha by the management practice of BMP that planting date on February 16th in the first cropping season of 2014.
3.2 Analysis of Impact on Crop Water Requirement and Field Irrigation Water for Different
Management Practice of Paddy Rice
The change trend of reference crop water (ET0) in Tainan, Taiwan in 2014 is at its peak in the late-June, the reference
crop water is 55.2mm at maximum. The result could be a reference for estimating the crop water requirement of first-season paddy rice. By estimating the above statistics, further cooperation with different planting date and crop coefficient would result in the crop water requirement of first season paddy rice. In figure 2, the first-season paddy rice is planted differently in 2014 during January 16th to June 4th and February 16th to June 14th, resulted in crop water requirement of 498mm and 450mm. The statistics could be explained by comparing the average crop water requirement. The growing period of time is under higher temperature when planting on February 16th, which the average crop water requirement is naturally higher than planting on January 16th with only shorter growing interval. Hence the crop water requirement of first-season paddy rice shows a trend of decrease as the planting date postponed.
Figure 2 Estimating on the crop water requirement of first-season paddy rice for different planting date
3.3 Analysis of the Impact on Management Practice to Yield Reduction Rate and Water Saving
Efficiency
In figure 3, the experimental result of 2014 shows similar trend in paddy rice yield reduction rate and water saving efficiency. In view of water saving efficiency, it reaches the best of 39.7% under the Modify SRI with single seedling and numerous seedlings; however the yield reduction rate is up to 7.2~16.5% that fails farmer’s expectation. In conclusion, the
WORKSHOP : PRECISION IRRIGATION FOR SUSTAINABLE CROP PRODUCTION
THE IMPACT OF MANAGEMENT PRACTICE ON YIELD AND IRRIGATION WATER USE EFFICIENCY FOR PADDY RICE UNDER SHORTAGE ENVIRONMENT
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overall evaluation of water saving efficiency and yield reduction rate: 1) the paddy rice field irrigation managing strategy is conducted under the regional rainfall, physiological characteristic of plant, rotation irrigation method and management practice; 2) on the plant date of February 16th and applying 7 days rotation irrigation interval in heading stage, the water saving efficiency could reach 27.3% with minor influence to the yield (3.5%). The water saving efficiency is significantly higher than only adjusting the plant date(14.1%). This finding could respond to the problem from climate change and spring drought, also advances the distribution and application performance of irrigation water use during water shortage period.
Figure 3 Analysis of impact on water saving efficiency and yield reduction rate for different Irrigation management practice
3.4 Analysis of the Impact on Management Practice to Water Resource Productivity
This paragraph analyzes irrigation water use efficiency with various irrigation management practice based on the water resource productivity index. In figure 4, the water resource productivity is 0.52 kg/m3 planting the first-season paddy rice in BMP on January 16th (controlled group). It is lower than 0.62
kg/m3 of adjusted plant date on February 16th. The irrigation management practice with better water resource productivity performance is in sequence of 1) 0.80 kg/m3 that plants on January 16th and applies Modify SRI with single seedling; 2) 0.72 kg/m3 that plants on January 16th and applies Modify SRI with numerous seedlings; 3) 0.69 kg/m3 that plants on February 16th and applies 7 days rotation irrigation interval in tillering stage. The above statistic indicates by applying Modify SRI would achieve the best results of water resource productivity.
Figure 4 Analysis of impact on water resource productivity for different Irrigation management practice of first-season paddy rice
4. Conclusion and Suggestion
This research applies the irrigation experiment design that combines regional rainfall, physiological characteristic of crops and rotation irrigation. The design adjusts irrigation management practice and plant date of first-season paddy rice with rotation irrigation according to the water requirement during the crop growing period, further establishes the irrigation managing strategy in water shortage period. In the overall evaluation of yield reduction rate and water saving rate, the field irrigation water of first-season paddy rice planted on February 16th has reached water saving efficiency of 14.1%~27.3%, comparing with the ones planted on January 16th.In addition, the field irrigation water of Modify SRI on January 16th has reached water saving efficiency of 39.7%, comparing with BMP on January 16th, but has influence on yield. On water resource productivity, Modify SRI with single seedling is also the best management practice. The paddy rice field irrigation managing strategy established from this research could respond to the climate change and severe water shortage problem in spring of Taiwan effectively, moreover advance the distribution and utility efficiency of irrigation water use in water shortage period. To view from the growing days and crop water requirement, the plant date of first crop adjusted from January 16th to February 16th, its growing days would change from 140 days to 119 days; and the accumulated crop water requirement from 498mm to 450mm.Thus the paddy rice growing days, crop water requirement and field irrigation water have all shown a trend of decrease according to the adjustment of plant date. The field irrigation water decreases due to the extension of rotation irrigation interval. This finding could be applied on facility preparation of paddy rice hovering stage and irrigation water use plan establishment.
REFERENCES
Barison, J., Uphoff, N., 2011. Rice yield and its relation to root growth and nutrient-use efficiency under SRI and conventional cultivation: an evaluation in Madagascar. Paddy and Water Environment 9: 65-78.
Chen, C.T., Lin, Y.J., Lee, C.H., 2013. The Effects of Different Cultivation Time on Yield and Irrigation Water Use Efficiency in Paddy Rice of Taiwan. Taiwan Water Conservancy 61: 98-107. (in Chinese)
Monteith, J. L., 1994. Proposed Calculation Procedures for ET0 Combination Formula. Bulletin of International
