田间补充灌溉施肥对菠萝生长、产量及水肥生产力的影响

为探明菠萝田间控水减肥效应及确定补充灌溉施肥水平,为粤西地区菠萝生产中节水节肥和提质增效提供依据。研究以金菠萝‘MD-2’为材料,设置无灌溉常规施肥（常规）,2个补灌W₁（-15~-35 kPa）和W₂（-35~-55 kPa）与3个肥料F₁（100%）、F₂（75%）和F₃（50%）梯度处理（F₁W₁、F₂W₁、F₃W₁、F₁W₂、F₂W₂、F₃W₂）,以无灌溉无施肥作为对照（CK）。研究菠萝光合面积、光合效率、干物质积累、经济性状、灌溉水生产力及肥料偏生产力对不同处理的响应。结果表明,补充灌溉施肥能够显著提高菠萝株高、叶长、叶宽、叶片数和植株干物质含量。水肥限制下,叶片数和叶长的减少是单株叶面积下降的主要因素,而光合面积的减小是干物质量下降的主要因素,菠萝植株生长受限来自于肥料减施和因干旱而导致的肥料利用受限。雨季干旱胁迫解除后叶片实际光化学效率（Φ_PSII）能够快速恢复,但营养生长期光合面积显著下降的不可逆转仍然导致果实干物质量和产量显著下降。补充灌溉施肥条件下肥料偏生产力表现为F₃>F₂>F₁,而果实田间产量和田间糖锤度均表现为F₃2≈F₁,因此确定F₂是最佳施肥水平;在F₂施肥水平下,水分生产力表现为W₂>W₁,但果实增产率和田间糖锤度在W₁和W₂之间差异不显著。因此,采用F₂W₂补充灌溉施肥方式可为菠萝生产中节水节肥和提质增效提供支撑。

Effect of Supplementary Fertigation on Pineapple Growth,Yield and Fertigation Production

Intensified seasonal drought turns into a crucial factor affecting tropic agricultural production only to pest and disease. From the autumn of 2014 to the spring of 2020, continuous days without effective precipitation exceeding 90 days and 120 days occurred in 4 years and 2 years, respectively. CAM-Cycling pathway makes pineapple a strong drought tolerance crop, but drought stress still restricts the growth and yield of pineapple even if it can live on. Heavy fertilization at the early growth stage without irrigation adopts in the production of pineapple due to the benefit limitation, which results in the decrease of yield and quality, low fertilizer utilization efficiency and farmland pollution. A major objective of this study is to investigate the effect of the supplementary fertigation on pineapple ‘MD-2’ at field condition. Two irrigation levels including W₁ (-15~-35 kPa), W₂ (-35~-55 kPa) and three fertilize levels including F₁ (100%), F₂ (75%), F₃ (50%) were conducted as F₁W₁, F₂W₁, F₃W₁, F₁W₂, F₂W₂, F₃W₂ and traditional fertilizer without irrigation to explore the effect on photosynthetic area, PSII quantum use efficiency (Φ_PSII), dry matter production, economic characters and fertigation production, taking non-fertigation as the contrast. The results showed that supplementary fertigation significantly improved the plant height, leaf length, leaf width, leaf number and dry matter production of pineapple. The decrease of leaf number and leaf length was the main factor that reduced the single plant leaf area under fertigation and photosynthetic area reduction resulted in the decrease of dry matter production. The significant difference of single plant leaf area and the aerial part dry matter production represented among the fertilizer levels rather than irrigation levels, confirmed that the adverse effects of pineapple growth under fertigation originated from the fertilizer reduction and limitation of fertilizer usage in drought. The PSII quantum use efficiency (Φ_PSII) of pineapple D-leaf without irrigation remained relatively high, which declined only 15% compared with irrigation treatment. Then it recovered after drought stress relieved in rainy season accompanied the reverse of the yellow leaf back to green. This phenomenon inferred that pineapple is insensitive to non-severe drought, the drought damage to pineapple leaf originate from the photoinhibition and photoreaction center regeneration might be the crucial assistance of the Φ_PSII recovery. But the irreversible reduction of photosynthetic area determined the decrease of fruit dry matter production and yield at harvest. Partial factor productivity showed F₃>F₂>F₁ while the yield and Brix showed F₃2≈F₁, which made F₂ the best fertilizer level. Irrigation water productivity represented W₂>W₁, between which no significant difference in yield and Brix was shown under F₂. Therefore, F₂W₂ is the appropriate supplementary fertigation pattern for pineapple production. In summary, pineapple is insensitive to non serve drought stress, maintaining the 20 cm depth soil water potential above -60 kPa guarantees the water requirement of pineapple, meanwhile, saves 25% of fertilizer consumption.