Abstract

Water scarcity and salinity are major concerns for the new intensive olive groves in arid and semi-arid areas in Tunisia. Furthermore, an inadequately applied fertilization program should aggravate the problem of salinity. The main aim of the present study is to assess the effects of salinity and ammonium nitrate (AN) on the behavior of olive plants (Olea europaea L.var. Arbequina). The experiment was performed with four NaCl levels (0.5, 50, 100, and 150 mM) combined with three levels of NH₄ NO₃ (0, 50, 100 g) by adding the nutrient solution of ½ Hoagland. Salinity had a statically significant negative effect on the considered responses, although the severity of the effect varies among treatments. High concentrations of salt (100, 150 mM) decreased vegetative growth, the production of fresh and dry biomass, leaf area, chlorophyll concentration, and increased leaf succulence. Similarly, salinity induced an accumulation of toxic ions and loss of electrolytes in the leaves. The use of ammonium nitrate is noticed to be ineffective in improving various growth and physiological parameters of olive plants grown under saline conditions, and it depressed all studied parameters mainly at the highest dose. This depression could be attributed to an increase in leaf sodium concentration after ammonium nitrate application, in spite of the increase of leaf nitrogen concentration. A better management of nitrogen fertilization in saline conditions should be considered mainly in relation to the right source.

摘要

突尼斯干旱和半干旱地区的新集约化橄榄园面临的主要问题是缺水和盐碱。此外，施肥计划应用不当会加剧盐度问题。本研究的主要目的是评估盐度和硝酸铵（AN）对橄榄植物（Olea europaea L.var。Arbequina）行为的影响。实验是在四种NaCl水平（0.5、50、100和150 mM）与三种水平的NH ₄ NO _{3结合下进行的}（0、50、100克）加入½Hoagland的营养液。盐度对所考虑的反应具有静态显着的负面影响，尽管影响的严重程度因治疗而异。高浓度盐（100，150 mM）会减少营养生长，新鲜和干燥生物量的产生，叶面积，叶绿素浓度并增加叶的多汁性。同样，盐度引起叶片中有毒离子的积累和电解质的损失。注意到硝酸铵的使用不能有效改善在盐条件下生长的橄榄植物的各种生长和生理参数，并且它主要在最高剂量时降低了所有研究的参数。这种降低可能归因于硝酸铵施用后叶片钠浓度的增加，尽管叶片氮含量增加。主要在正确的来源方面，应考虑在盐条件下更好地管理氮肥。