GROWTH EVOLUTION OF CACTUS FORAGE DRIP IRRIGATED

ABSTRACT: The objective was to evaluate the growth of clones of forage cactus, subjected to different conditions of water availability in the Brazilian Semiarid, during a year of climate anomaly (biennium 2012-2013). The experiment was carried out in the first production year of the second crop cycle (March 2012 to February 2013), in the district of Serra Talhada, State of Pernambuco. The experiment was carried out in a randomized block design using a factorial arrangement 3x3 with three replications, being used three intervals of application of a fixed irrigation depth (7.5 mm), (7, 14 and 28 days), and three forage cactus clones (IPA: IPA Sertânia; MIU: Míuda and, OEM: Orelha de Elefante Mexicana). Eight biometric campaigns were performed during the experiment period for morphological analysis of the plants and cladodes along the time. It was found that water availability conditions showed no significant influence (P>0.05) on the majority of the absolute and relative values of the growth variables of the three forage cactus clones. However, when comparisons were performed among different clones, regardless of the water availability conditions, it was observed that, in terms of absolute values, the OEM had the highest means, differing only from the MIU clone. Regarding evaluations over time, there were increased growth rates in the last months of the crop cycle because of the occurrence of rainfall, which in conjunction with the application of the irrigation treatments promoted the best biometric increments for the OEM and IPA Sertânia clones.摘要：本研究旨在评估巴西半干旱地区不同供水条件下饲用仙人掌克隆株系的生长表现，试验周期为2012-2013年气候异常的两年期。实验于巴西伯南布哥州塞拉塔尔哈达地区开展，时段为第二个种植周期的首个生产年（2012年3月至2013年2月）。实验采用随机区组设计，设置3×3因子试验方案并设3次重复：固定灌溉深度为7.5mm，设置3个灌溉间隔梯度（7天、14天、28天）；供试饲用仙人掌克隆株系共3类，分别为IPA（IPA Sertânia）、MIU（Míuda）以及OEM（墨西哥象耳仙人掌，Orelha de Elefante Mexicana）。试验期间共开展8次生物测定采样，用于随时间推移对植株及肉质茎片开展形态学分析。结果显示，供水条件对3个饲用仙人掌克隆株系的绝大多数生长指标的绝对值与相对值均无显著影响（P>0.05）。然而，在不考虑供水条件的前提下对不同克隆株系进行组间比较时可观察到：就生长指标的绝对数值而言，OEM克隆株系的均值最高，仅与MIU克隆株系存在显著差异。就随时间的动态评估结果而言，种植周期末期因降雨事件出现，植株生长速率有所提升；结合灌溉处理的实施，为OEM与IPA Sertânia克隆株系带来了最优的生物指标增量。