무논 써레질과 마른논 써레질의 벼 생육과 메탄 배출량 비교 = Comparison of rice growth and methane emissions between puddling and non-puddling

다국어 초록 (Multilingual Abstract)

Before planting rice in the paddy field, puddling is an important cultivation method for rice rootage and growth. It is the process of breaking up the soil and leveling the ground. However, there are some problems such as water pollution when introducing puddling. Because field preparation working is generally performed in irrigated paddy, puddling generates turbid water which can flow into rivers or lakes. Meanwhile, puddling is no longer considered as an essential field process because of the developments of agricultural machinery and alternative methods. As a result of advancements in science and technology, new cultivation techniques have emerged such as non-puddling. Because non-puddling is performed under drained paddy conditions, it can prevent non-point source pollution. Also, non-puddling helps to distribute labor more evenly during the peak farming season since it can allow rotary to begin relatively early. Despite its many cultivation advantages, there are still significant challenges to overcome in adopting non-puddling. For instance, there is not enough research on whether stable rice yield and quality in non-puddling are comparable to those of puddling. Including rice growth, there is insufficient data regarding the changed soil physical properties and its impact on methane emissions. To this end, two experiments were designed in this study. Experiment 1 was conducted in pots and drums in the greenhouse. Experiment 2 was performed in rice paddy. In experiment 1, crop environments and rice growth were investigated. For crop environments, soil hardness, soil porosity, soil bulk density, fall of water, and redox potential were monitored. When non-puddling was performed, soil hardness tended to be lower and soil porosity tended to be higher, which is likely due to differences in puddling intensity and an increase in soil hardness during drying in puddling. As a result, fall of water was relatively increased and redox potential was higher values in the non-puddled soil. In rice growth, dry weight, leaf area, plant height, number of tillers, bleeding rate, nitrogen concentration, and yield were compared. Under non-puddled conditions, rice root establishment and above-ground growth were improved at the rooting stage likely due to relatively lower soil hardness and better soil aggregates. After rooting stage, leaf, panicle, and root dry weight were not statistically significant. Stem dry weight was significantly higher in non-puddling at the tillering stage, but no significant differences were observed after tillering stage. The difference in stem dry weight at the tillering stage was likely due to the difference in bleeding rate between puddling pot rice and non-puddling pot rice. The bleeding rate which is an indicator for assessing rice growth was higher in the non-puddling at the tillering stage and this is considered to be the outcome of enhanced water and nutrient uptake driven by the rapid rice rootage at the rooting stage in non-puddling. For yield, number of panicles per m2, number of spikelets per panicle, ripening ratio and weight of 1,000 grains were investigated. Each yield component showed no significant difference between puddling and non-puddling. Although there were several differences in rice growth investigation results between puddling and non-puddling at the rooting stage, no differences in yield components were observed, which may be attributed to changes in soil clogging and similar rice tiller numbers over the cultivation period between puddling and non-puddling. In experiment 2, soil environments, rice growth, yield and methane flux were analyzed. In soil environment results including physical properties, soil porosity and redox potential were relatively higher under non-puddled conditions during a specific period, and there was no statistically significant difference in soil temperature. The differences in soil porosity and redox potential were attributed to soil compaction and disrupted soil aggregates due to different puddling intensity between puddling and non-puddling. As a result of changes in soil physical properties, methane emissions were reduced in non-puddled paddy. In rice growth, no differences in rice dry weight were observed between puddling and non-puddling across the five growth stages (young panicle formation, booting, heading, early ripening, late ripening). Also, non-puddling showed stable rice yield, amylose content, protein content, and percentage of head rice without any differences compared to puddling. Through findings, it is concluded that non-puddling facilitates rice rootage at the rooting stage and shows stable rice growth and yield compared to puddling. Additionally, because it has many benefits such as water pollution reduction, climate change adaptation by reducing methane emissions, and others, this study is expected to be utilized as a technical reference for the adoption of new cultivation technology, non-puddling.

목차 (Table of Contents)

• 1. 서언 1
• 2. 재료 및 방법 5
• 2.1. 실험 재료 및 설계 5
• 2.1.1. 포트 조건에서의 무논 써레와 마른논 써레에 따른 토양 환경 차이 및 작물 생육 비교 (시험 1) 5
• 2.1.2. 포장에서 무논 써레와 마른논 써레에 따른 메탄 배출 관측과 수량 및 품질 비교 (시험 2) 8
• 2.2. 통계 처리 10
• 3. 결과 11
• 3.1. 포트 조건에서의 무논 써레와 마른논 써레에 따른 토양 환경 차이 및 작물 생육 비교 11
• 3.1.1. 시험 전 토양 분석과 재배 환경 미기상 11
• 3.1.2. 포트 조건에서의 무논 써레와 마른논 써레의 토양 물리성 및 재배 환경 차이 14
• 3.1.3. 포트 조건에서의 무논 써레와 마른논 써레에 따른 작물 생육 비교 21
• 3.2. 포장에서 무논 써레와 마른논 써레에 따른 메탄 배출 관측과 수량 및 품질 비교 34
• 3.2.1. 포장에서 무논 써레와 마른논 써레에 따른 토양 물리성 변화 및 메탄 플럭스 산출 34
• 3.2.2. 포장에서 무논 써레와 마른논 써레에 따른 작물 생육과 수량 및 품질 비교 40
• 4. 고찰 46
• 4.1. 무논 써레질과 마른논 써레질이 착근기 벼 뿌리 활착에 미치는 영향 (시험 1) 46
• 4.2. 무논 써레와 마른논 써레의 재배 환경 차이 해석 (시험 1) 47
• 4.3. 마른논 써레질의 메탄 발생 저감 효과 (시험 2) 48
• 4.4. 무논 써레와 마른논 써레의 작물 생육과 수량 및 품질 비교 (시험 1, 시험 2) 50
• 5. 적요 54
• 6. 참고문헌 56