كليدواژه لاتين :
Physiological parameters, morphological parameters, soil cover, jujube, low irrigation
چكيده انگليسي :
Drought stress is the most important factor affecting plant growth in arid and semi-arid regions and plays a greater role in the establishment of seedlings in an ecosystem than other abiotic stresses. Considering the arid and semi-arid climate of Iran and the limitation of water resources and the medicinal and economic value of jujube trees, knowledge of the water requirement and the level of resistance of this species to different levels of drought stress seems essential. Therefore, this research aims to investigate the effect of mulch management (including M1: without using plant residues, M2: using plant residues on the soil surface and M3: mixing plant residues with the surface layer of the soil up to a depth of 30 cm) on reducing water consumption and growth Jujube tree in different levels of irrigation (including FI: 0.15: irrigation with 50% of full irrigation and 0.25 FI: irrigation with 25% of full irrigation). At the end of the growth period, the parameters of applied water amount, evaporation-transpiration of the entire growth period, seedling height, trunk diameter, number of secondary branches, relative leaf water content, ion leakage percentage, chlorophyll a and b values, chlorophyll a to b ratio, leaf area , the crown volume and shade diameter were measured. The results showed that the main effects of soil cover on the parameters of height, relative leaf water content, chlorophyll b, chlorophyll a to b ratio, leaf area, canopy volume and shade diameter were significant at the level of one percent and seedling diameter and ion leakage at the level of five percent. The main effects of irrigation on all mentioned parameters were significant except the ratio of chlorophyll a to b. The interaction effect of the treatments was significant only on the parameters of chlorophyll a to b ratio and leaf surface.full irrigation, FI 0.75: The main effects of irrigation on all mentioned parameters were significant except the ratio of chlorophyll a to b. The interaction effect of the treatments was significant only on the parameters of chlorophyll a to b ratio and leaf surface. The results showed that by applying 25, 50 and 75% less irrigation, water consumption was saved by 29, 51 and 74%, respectively. Also, the use of M2 and M3 treatments compared to the control led to a decrease in water consumption by 16 and 9%. The highest and lowest seedling height was observed in FI 0.75 (90.44 cm) and FI 0.25 (79 cm) treatments, respectively. The highest and lowest seedling diameter and the number of secondary branches were obtained in full irrigation treatments (1.42 cm, 5.33) and FI 0.50 (1.2 cm and 3), respectively. irrigation with 75% of full . In the parameters of relative leaf water content, chlorophyll a and b, canopy volume and canopy diameter, the highest and lowest values were respectively in full irrigation treatments (85.4%, 0.23 µg/ml, 0.09 µg/ml, 16507 cm3 and 36.87 cm) and FI 0.25 (67.32%, 0.17 μg/ml, 0.07 μg/ml, 8575.52 cm3 and 28.21 cm) were obtained. The highest and lowest amount of ion leakage was observed in FI 0.25 (48.74%) and full irrigation (33.33%) treatments, respectively. The use of soil cover increases the parameters of seedling height and diameter, the relative content of leaf water, the volume of the canopy It reduced chlorophyll b and ion leakage. The application of mulch on the soil surface caused an increase of 8.69%, 15% and 13.95% respectively in seedling height, trunk diameter and relative leaf water content compared to the control treatment (M1). The largest canopy volume was observed in the soil cover treatment mixed with the soil surface layer (M3). No significant difference was observed between M2 and M3 treatments in most of the measured characteristics. The use of mulch by maintaining soil moisture is effective in reducing water consumption and increasing the growth characteristics of jujube even with low irrigation by 25%. Therefore, by applying 25% less irrigation (FI treatment 0.75) and using plant residues on the soil surface, it is possible to achieve a favorable performance in the cultivation of jujube seedlings while saving water consumption and preserving limited water resources.and the
