熱帶氣候條件下之水稻永續灌溉管理

Sustainable Irrigation Management for Paddy Rice in Tropical Climate Conditions

威多諾(Victoriano Joseph Pascual)

指導教授 ： 王裕民

國立屏東科技大學/國際學院/熱帶農業暨國際合作系/博士(2016年)

摘要

在現今的社會中，灌溉農業為世界人口主要的生產食物方式；而農業正面臨著兩個主要挑戰：需要大量且持續的生產糧食，以滿足世界人口的不斷增長，同時在缺水的條件下完成。
本研究在台灣南部針對水稻產量、生長反應、不同節水管理方式之實踐技術進行研究；節水技術如乾濕交替灌溉（AWDI）和控制排水可以更節省水的使用，同時仍保持可接受的糧食產量；此外，水稻強化栽培系統（SRI），已經成為一套可以透過更強壯和更健康的植物及土壤保持更高的產量，同時減少外部資源的投入之指導原則。
在台灣，節約用水的技術在低地稻米灌溉是必須的，因為氣候變遷可能導致季風降雨的不確定性，造成灌溉用水可能減少；然而，在氣候變遷的情況下，利用季節性條件下有利之水量優勢來提高作物產量和灌溉水利用效率時，可以優化節水措施；因此，本研究的第一部分是結合四個不同的水深處理（T2cm，T3cm，T4cm，T5cm），同時利用降雨透過完全隨機區集設計系統，以四次重複試驗來找到減少水稻灌溉水合適的水深，從移植至抽穗採用每週水深控制。
第二個研究是為了評估低地水稻在SRI管理下的表現，這個實驗在雨季進行，由4個水資源管理措施和4次重複試驗組成：（1）T2cm，排出2cm深的過量雨水並以相同的量再次灌溉、（2）T4cm，排出4cm深的過量雨水並以相同的量再次灌溉、（3）T6cm，排出6cm深的過量雨水，並以相同的量再次灌溉、（4）TSat，在作物週期中，試驗田保持飽和或淹沒。
第三項研究亦針對於SRI的管理，但是是在旱季期間進行，因為在旱季SRI對水稻適應力，生長和節水的知識仍然有限。實驗設計為完全隨機區集設計，包括四次重複試驗和兩個水稻品種台南11號（TN11）和台東30號（TD30）。灌溉方案評估包含（a）連續淹灌（CF）以（TN11CF和TD30CF）表示，（b）間歇灌溉，3天的間隔（TN113和TD303）和（c）間歇灌溉，7天的間隔（TN117和TD307）。在間歇灌溉方案中移植後的前5天應用3-6cm的池水深度，然後連續灌溉3和7天的間隔，直到收成的前一週。在CF模式下，在移植相同的持續時間後，立即採用4-7cm水深。實驗結果表明：在AWDI條件下，T5cm雨水的生產率最高（2.07kg / m3），T2cm最低（1.62kg / m3）；在T2cm達到最高的總生產率（0.75kg / m3）和灌溉水生產率（1.40kg / m3）；在T4cm，T3cm和T2cm中節約的總水量分別為20％，40％和60％。從移植至抽穗，每週水深控制在T4cm水深，與T5cm相比，最低產量減少（1.57％）和穀物生產損失（0.06kg），對產量損失沒有顯著影響。實驗二的結果表明，抽穗開始後，水分的減少對T2cm和T4cm的植株高度及T2cm的穀粒產量顯著影響。T4cm中最低顆粒減少產（4.92％）和顆粒產量損失（0.09kg）；T2cm中產生最高的總生產率（0.52kg /m 3）和灌溉水生產率（1.88kg / m 3），其次為T4cm的總生產率（0.44kg /m 3）和灌溉水生產率（1.14kg / m 3）。在產量和節約灌溉水方面，在4厘米深度排放過量的降雨並提供相同量的灌溉用水，在SRI管理下提供了最好的結果。實驗三的結果表明，與連續淹灌方式相比，3天和7天的間歇灌溉間隔所節省的用水55％和74％，總水分生產率以7天間歇灌溉為最大，產量為0.35kg grain / m3（TN117）和0.46kg grain / m3（TD307）。與TN11F相比，TN113和TN117的平均穗量減少166％和196％，與TD30F相比，TD303（150％）和TD307（156％）的降低量相似。在穀物產量比較中，TD30品種的產量是相似的。然而在TN11品種中， TN117的穀粒產量比TN11F降低了30.29％。最後比較不同間歇灌溉方式之植物高度、葉面積和總葉綠素，發現3天間隔的間歇灌溉方式大於其他間歇灌溉方式。

關鍵字

水稻強化栽培系統 ； 乾濕交替灌溉 ； 間歇灌溉 ； 用水效率 ； 氣候變遷 ； 稻米 ； 排水控制

並列摘要

Irrigated agriculture plays a vital role in the production of food for the world’s population. Agriculture faces two major challenges. First, it needs to enhance food production sustainably to feed a growing world population; at the same time, this increase needs to be accomplished under conditions of increasing water scarcity. This study investigated rice yield, growth response and water saving under different water saving management practices and technology in southern Taiwan. Water saving technology such as alternate wetting and drying irrigation (AWDI) and controlled drainage may help to minimize water loss while still maintaining an acceptable yield. In addition, the system of rice intensification (SRI) has emerge as a set of guiding principles that can maintain higher yields through stronger and healthier plants and soils while reducing external inputs. The adoption of water saving technology in irrigated lowland rice is essential in Taiwan, as climate change may cause the uncertainty of monsoon rainfall which may decrease the availability of irrigation water. However, under climate change circumstances water saving measure can be optimized when taking advantage of favorable water seasonality to increase crop yield and irrigation water use efficiency. Therefore, the first research in this study was to find a suitable water depth for reducing rice irrigation water use using four different water depth treatment (T2cm, T3cm, T4cm, T5cm) while utilizing rainfall through a complete randomized block design system having four replications. Water depths were applied weekly from transplanting to heading. The second focus of this research was conducted to evaluate the performance of lowland paddy rice under SRI management practices and controlled drainage. This experiment was performed during the rainy season; the treatments consisted of 4 water management practices and 4 replications: (1) T2cm, draining of excess rain water at 2cm depth and re-irrigating at same amount (2) T4cm, draining of excess rain water at 4cm and re-irrigating at same amount (3) T6cm, draining of excess rain water at 6cm and re-irrigating of same amount (4) TSat, plots remained saturated or flooded during the crop cycle. The third research also focused on SRI management practices however it was conducted during dry season as there is still limited knowledge about rice adaptation, growth and water saving under SRI during this time. The experiment was laid out in a complete randomized block design consisting of four replications and two rice varieties Tainan11 (TN11) and Tidung30 (TD30). The irrigation regimes evaluated were (a) continuous flooding (CF) represented as (TN11CF and TD30CF), (b) intermittent irrigation at 3days interval (TN113 and TD303) and (c) intermittent irrigation at 7days interval (TN117 and TD307). Ponded water depths of 3-6cm were applied for the first 5 days after transplanting in intermittent irrigation regimes thereafter successive irrigation of 3 and 7days intervals followed until one week before harvest. Under CF regime, 4-7cm ponded water depth was applied immediately after transplanting for the same duration. The results from experiment one showed that under AWDI the highest rainwater productivity (2.07kg/m3) was achieved in T5cm and the lowest in T2cm (1.62kg/m3). The highest total water productivity, (0.75kg/m3) and irrigation water productivity (1.40kg/m3) was achieved in T2cm. The total amount of water saved in T4cm, T3cm and T2cm was 20, 40 and 60% respectively. Weekly application of T4cm ponded water depth from transplanting to heading produced the lowest yield reduction (1.57%) and grain production loss (0.06kg) having no significant impact on yield loss compared to T5cm. Findings from experiment two suggests that water reduction after panicle initiation significantly affected plant height in T2cm and T4cm, and grain yield in T2cm. The lowest grain reduction (4.92%) and grain production loss (0.09 kg) was produced by T4cm. The highest total water productivity (0.52kg/m3) and irrigation water productivity (1.88 kg/m3) was produced in T2cm followed by T4cm (0.44 kg/m3) and (1.14kg/m3) respectively. The draining of excess rainfall at 4cm depth and providing irrigation of the same amount provided the best results under SRI management in terms of yield and irrigation water saving. The results obtained in experiment three showed that intermittent irrigation of 3 and 7days intervals produced water savings of 55% and 74% compared with continuous flooding. Total water productivity was greater with intermittent irrigation at 7days intervals producing 0.35kg grain/m3 (TN117) and 0.46kg grain/m3 (TD307). Average daily headed panicle reduced by 166% and 196% for TN113 and TN117 compared with TN11F, with similar reduction recorded for TD303 (150% ) and TD307 (156%) compared with TD30F. Grain yield of TD30 variety was comparable among irrigation regimes, however, it reduced by 30.29% in TN117 compared to TN11F. Plant height, leaf area and total chlorophyll was greater in plants exposed to intermittent irrigation of 3 days intervals.

並列關鍵字

System of Rice Intensification ； Alternate Wetting and Drying ； intermittent irrigation ； water use efficiency ； climate change ； rice ； controlled drainage

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