CAJ | 학술논문

为了确定甘蔗水分亏缺诊断指标及其临界值，该文以新台糖22号为试验材料，通过盆栽和大田试验研究了水分胁迫下甘蔗全生育期植株茎直径变化特征，然后利用盆栽试验数据分析了盆栽甘蔗的茎直径变化指标日最大收缩量（maximum daily shrinkage，MDS）、日增长量（daily increase，DI）和土壤水分的关系，回归建立了基于MDS和DI的甘蔗水分亏缺诊断模型。大田和盆栽试验均表明，甘蔗处于苗期、分蘖期和伸长期的茎生长阶段，土壤水分差异导致的茎生长差异显著（P＜0.01）。盆栽试验表明60%以下田间持水率的水分胁迫（中度及重度干旱）在茎生长阶段均可使甘蔗茎直径增长总量降低约41.7%～100%，且对甘蔗茎直径增长的影响以伸长期最大，分蘖期次之，苗期最小；在甘蔗成熟期，16个观测日正常、轻、中和重旱茎直径总增长量分别为0.049、0.055、0.048和0.033 mm，该阶段茎秆基本停止生长，土壤水分差异导致的茎生长差异不显著（P＞0.05），成熟期对水分亏缺最不敏感。对各生育期的MDS和DI与土壤含水率的回归分析结果表明，除成熟期DI指标外，其他各生育期的MDS和DI均与土壤含水率显著线性相关，决定系数在0.501～0.765之间。苗期MDS、分蘖期和伸长期的 DI 能更好地诊断水分亏缺。所建立的模型可较好的诊断甘蔗水分亏缺，研究结果可为利用茎直径变化指导甘蔗灌溉提供理论依据。
위료학정감자수분우결진단지표급기림계치，해문이신태당22호위시험재료，통과분재화대전시험연구료수분협박하감자전생육기식주경직경변화특정，연후이용분재시험수거분석료분재감자적경직경변화지표일최대수축량（maximum daily shrinkage，MDS）、일증장량（daily increase，DI）화토양수분적관계，회귀건립료기우MDS화DI적감자수분우결진단모형。대전화분재시험균표명，감자처우묘기、분얼기화신장기적경생장계단，토양수분차이도치적경생장차이현저（P＜0.01）。분재시험표명60%이하전간지수솔적수분협박（중도급중도간한）재경생장계단균가사감자경직경증장총량강저약41.7%～100%，차대감자경직경증장적영향이신장기최대，분얼기차지，묘기최소；재감자성숙기，16개관측일정상、경、중화중한경직경총증장량분별위0.049、0.055、0.048화0.033 mm，해계단경간기본정지생장，토양수분차이도치적경생장차이불현저（P＞0.05），성숙기대수분우결최불민감。대각생육기적MDS화DI여토양함수솔적회귀분석결과표명，제성숙기DI지표외，기타각생육기적MDS화DI균여토양함수솔현저선성상관，결정계수재0.501～0.765지간。묘기MDS、분얼기화신장기적 DI 능경호지진단수분우결。소건립적모형가교호적진단감자수분우결，연구결과가위이용경직경변화지도감자관개제공이론의거。
In order to test the feasibility of diagnosing water deficiency of sugarcane using parameters related with stem diameter variations, both pot experiment and field experiment were conducted. In the pot experiment, pots were selected with 60 cm in length and width, and 40 cm in depth. Sugarcane t22 was planted in pots and field. Stem diameter variations were continuously measured. The diurnal variations of stem diameter at different growing stages under different water deficits were investigated, and maximum daily shrinkage (MDS) and daily increase (DI) were calculated based on relative variations (RV) of stem. In addition, the correlations between MDS, DI (from pot experiment) and soil moisture were analyzed. A water deficiency diagnosis model was established and assessed by the F test. The results showed that RV values were significantly (P<0.01) different among different soil moisture treatments during the stem growing period include of seedling, tillering and elongating stage. The overall growth of sugarcane stem diameter was reduced by about 41.7% to 100% as soil moisture was less than 60% of field capacity. Elongating stage was most sensitive to soil moisture deficiency, followed by tillering stage and seedling stage. At the stem mature period (that was sugarcane’s mature stage), the total amount of stem diameter growth (sugarcane planted in pots) was 0.049, 0.055, 0.048 and 0.033 mm in 16 observation days under conditions of normal irrigation, light drought, moderate drought and severe drought, respectively. The growth of stem diameter basically stopped at this stage and thus it was the least sensitive to water deficits. The regression analysis showed that MDS and DI were significantly correlated (P<0.01) with soil water content at different growing stages of stem except for DI at mature stage, the coefficient of determination was 0.501-0.765. During the stem growing period include seedling, tillering and elongating stage, MDS and DI both had high response to water stress, and hence could be reliable indicators for diagnosing water status in sugarcane. MDS was more reliable at seedling and elongating stage, while DI was better indicators at tillering stage from the results of the coefficient of determination and root mean squared error. At the mature stages, MDS was more reliable due to its high sensitivity to water deficits. The upper and lower values of soil moisture were inputted as variable values into the regression equation, and thereby the threshold range of MDS and DI under water stress was determined. At the seedling stage, the MDS of 0.026-0.052 mm or DI of 0.087-0.160 mm indicated the soil was in a moderate drought condition, and the MDS of 0.052-0.078 mm or DI of 0.012-0.087 mm indicated the soil was in a severe drought condition. At the tillering stage, the MDS of 0.046-0.099 mm or DI of 0.256-0.111 mm indicated the soil was in a moderate drought condition, and the MDS of 0.099-0.153 mm or DI of-0.038-0. 111 mm indicated the soil was in a severe drought condition. At the elongating stage, the MDS of 0.082-0.174 mm or DI of-0.013-0.189 mm indicated the soil was in a moderate drought condition, and the MDS of 0.174-0.266 mm or DI of-0.216--0.013 mm indicated the soil was in a severe drought condition. At the mature stage, the MDS of 0.072-0.111 mm indicated the soil was in a severe drought condition. The F test indicated that the established models could reliably predict water deficiency, and the coefficient of determination for prediction was between 0.515-0.787. The determined indicator, as well as the established water deficiency diagnosis models, is valuable for studies on irrigation scheduling for sugarcane based on stem diameter variations.