Impact of Irradiated Compost on Growth and Nutritional Status of Valencia Orange Grown in the Desert Areas

Aims: To evaluate the effect of compost application whether irradiated or not in addition to recommended mineral fertilization on growth and nutritional status of Valencia orange trees.

Study Design: The design of the study is a randomized complete block design. The study was done on five-years-old Valencia orange grown in a loamy sand soil.

Place and Duration of Study: The study was conducted in El-Shrouk yard -Cairo-Alexandria Desert Road through five successive seasons 2014, 2015, 2016, 2017 and 2018. Compost irradiation was done at the National Centre for Radiation Research and Technology, Atomic Energy Authority.

Methodology: In addition to mineral fertilization, four main treatments were applied to Valencia orange trees, T1 three years application of non-irradiated compost, T2 four years application of non- irradiated compost, T3 and T4 similar to T1 and T2 while irradiated compost was applied. Shoot length and thickness, leaf number and area were calculated. Leaf N, P and K% as well as Fe, Mn, Zn and total chlorophyll content were measured.

Results: Data revealed that application of compost especially irradiated form in combination with chemical fertilizers has a positive effect on vegetative growth of Valencia orange trees in addition to leaf content of nitrogen, phosphorus, potassium, iron, manganese, zinc and total chlorophyll. Four years application of compost regardless irradiation was superior to three years application. Combination of irradiated compost and four years application gave the highest values for the previously mentioned parameters.

Conclusion: Addition of compost to chemical fertilizers improved the vegetative growth and nutritional status of Valencia orange trees. Irradiation of compost increased its efficiency that might reduce the time of application. Also, using compost, particularly in the newly reclaimed soil, greatly increase water and mineral fertilizers use efficiency, which in turn lead to saving in irrigation water and fertilization nutrients.