EFFECT OF SKIPPING ONE IRRIGATION DURING DIFFERENT GROWTH STAGES AND FOLIAR APPLICATION OF MICRONUTRIENTS ON ROSELLE (HIBISCUS SABDARIFFA, L.) PLANTS AND SOME WATER RELATIONS IN HEAVY CLAY SOILS

Document Type : Original Article

Abstract

Water considers the most important component of life, it is rapidly
becoming a critically short commodity for humans and crop production.
Drought is one of the major a biotic stresses in agriculture worldwide. In order
to study the effect of water stress (skipping one irrigation at vegetative,
flowering and fruits formation growth stages) in comparison with traditional
irrigation in addition to foliar application of chelated iron , zinc , manganese
and their combination on growth , productivity of dark roselle (Hibiscus
sabdariffa, L.) plants and some water relations under surface irrigation
system. Two field experiments were conducted at the Experimental Farm of
Sakha Horticulture Research Station, Kafr El-Sheikh Governorate during the
summer seasons of 2014 and 2015. The results revealed that skipping one
irrigation at any of the three studied stages significantly reduced all the tested
growth parameters and yield production as compared with unstressed plants
(control). However, subjecting roselle plants to water stress at flowering stage
had the most negative effect on growth parameters and yield production. On
the other hand, water stress had a stimulating effect on chemical composition
(total anthocyanin, T.S.S, acidity%, pH and T.S.S acidity ratio). The present
study also indicated that foliar application of chelated Fe ,Zn, Mn and
combination among them had a positive effect on growth parameters, yield
and chemical composition but chelated Zn application surpassed the other
nutrients in counteracted the deleterious effects of stress on chemical
composition. Application of chelated Fe+ Zn + Mn showed the significant
increasing in calyxes yield/fed, fibers yield/fed and seeds yield/fed. Also, the
highest overall mean values for seasonal amount of water applied,
consumptive use, water productivity and productivity of irrigation water for all
plant organs were recorded under traditional irrigation. Meanwhile, the lowest
overall mean values were recorded under water stress treatments and the
amount of water saving is 8.89%. Concerning, micronutrients as foliar
application, the highest overall mean values were recorded under application
of chelated (Fe+Zn+Mn) in comparison with non-application and application
every nutrient as alone. Regarding, consumptive use efficiency, the highest
mean values were recorded under skipping one irrigation at vegetative growth
stage, but the lowest were recorded under traditional irrigation. Also, the
highest values were recorded under foliar application treatment (Fe+Zn+Mn)
comparing with non- application and application every nutrient as alone .This
study can be concluded that skipping one irrigation at vegetative growth stage
when cultivated roselle plants under studying region with chelated ( Fe+ Zn+
Mn) foliar application which counteracted the deleterious effects of stress and
chelated Zn foliar application only to increase chemical component
.Nevertheless, reduction in yield offset saving nearly 9% of water applied.

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