Growth and yield of cactus pear under irrigation frequencies and nitrogen fertilization

ABSTRACT Microirrigation associated with nitrogen (N) fertilization aims to meet the water and nutritional demands of cactus pear. The objective of this study was to evaluate the growth and yield of cactus pear (Opuntia ficus-indica) irrigated by microirrigation and fertilized with N. The experiment was conducted in the field at the Poço Redondo farm, Santa Luzia, PB, Brazil (6° 52’ 27’’ S and 36º 56’ 0’’ W and altitude of 299 m), between April and December 2017. The experimental design was in randomized blocks in a 5 x 2 factorial scheme, with five irrigation frequencies (7, 14, 21, 28 and 35 days) and two types of fertilization (soil fertilized with N and not fertilized) in the cultivar ‘Orelha de Elefante Mexicana’, with three replicates. Different irrigation frequencies promote reduction in green biomass yield and increase in the economic water productivity when using of the cladode for propagative material. Nitrogen fertilization increased growth, green biomass yield, water productivity and economic water productivity. The greatest economic return is obtained by producing cladodes marketed for propagative material. Reducing the frequency of irrigation promotes greater water saving, increasing the irrigated area and production by using less water at high frequency.

摘要：结合氮肥（nitrogen, N）的微灌（microirrigation）技术，旨在满足梨果仙人掌的水分与养分需求。本研究以梨果仙人掌（*Opuntia ficus-indica*）为供试材料，评估微灌与氮肥施加对其生长及产量的影响。试验于2017年4月至12月在巴西帕拉伊巴州圣卢西亚的Poço Redondo农场大田开展，试验点地理坐标为南纬6°52′27″、西经36°56′0″，海拔299米。试验采用5×2析因的随机区组设计，设置5个灌溉频率梯度（7、14、21、28、35天）与2种施肥处理（施加氮肥与不施肥），供试品种为‘Orelha de Elefante Mexicana’，每组处理设置3次重复。当以仙人掌扁茎（cladode）作为繁殖材料（propagative material）时，不同灌溉频率会降低青绿生物量产量（green biomass yield），却提升经济水生产力（economic water productivity）；氮肥施用可显著提升植株生长势、青绿生物量产量、水生产力与经济水生产力；以生产可作为商品的繁殖用扁茎为目标时，可获得最高经济收益；降低灌溉频率可实现更优的节水效果，而采用高频灌溉并减少用水量，则可扩大灌溉面积并提升总产量。