Photosynthetically active radiation in strawberry produced in stair-like containers

ABSTRACT In intensive hydroponic systems, such vertical and pyramidal systems, photosynthetically active radiation (PAR) and integrated (IPAR) may be intercepted by the containers and the leaf area of the plants grown in the upper strata, decreasing fruit yields and quality. The objective of this study was to evaluate the behavior of PAR and IPAR at different planting heights and the effect of geographic orientation and fruit yield and quality of strawberry produced in stair-like containers. The factors were four heights of the container (0.20, 0.50, 0.80 and 1.10 m) and two orientations (east and west). At each height and orientation of the container, PAR and IPAR, yield and fruit total soluble solids were measured. PAR and IPAR were statistically different at all heights evaluated and were highest in the highest containers. The east and west orientation of the containers was significantly different in the morning and in the afternoon for PAR and IPAR, while daily average values were equal. Yield on average was 47% higher in plants cultivated in containers at heights of 0.50, 0.80 and 1.10 m, relative to those in 0.20 m high containers. Fruits grown in the highest containers had higher values of total soluble solids.

摘要 在立式、金字塔形等集约化水培系统中，光合有效辐射（Photosynthetically Active Radiation，PAR）与整合光合有效辐射（Integrated Photosynthetically Active Radiation，IPAR）可能被上层栽培层的容器与植株叶面积拦截，进而导致果实产量与品质下降。本研究旨在评估不同栽培高度下PAR与IPAR的变化特征，并探究栽培方位对阶梯式容器栽培草莓的果实产量及品质的影响。本试验设置两个试验因素：4个容器栽培高度（0.20、0.50、0.80、1.10 m）以及2个栽培方位（东、西）。在各栽培高度与方位的容器位置，分别测定PAR、IPAR、果实产量以及果实总可溶性固形物含量。结果表明，所有测定高度下PAR与IPAR均存在显著统计学差异，且最高层栽培容器中的PAR与IPAR数值最高。在上午与下午时段，容器东、西方位的PAR与IPAR存在显著差异，但二者的日平均数值无显著区别。相较于栽培高度为0.20 m的容器，高度为0.50、0.80、1.10 m的栽培植株平均产量提升47%。最高层栽培容器所结草莓的总可溶性固形物含量更高。