Effect of Substrate Type and Fertilizing Management Programs on Yield and Nitrate Content of Both Molokhia and Spinach Grown on Rooftops in Egypt

Abstract

leafy vegetables like molokhia and spinach are very popular vegetable crops for egyptian and known for it's high values in vitamins and nutients. For that, two experiments have been conducted (one experiment for molokhia and the second one for spinach) to invistigate the effect of substrate type and fertilizing management programs on yield and nitrate content of both molokhia and spinach grown on rooftops in Egypt. The two experiments have been conducted in the rooftop garden of Central Laboratory for Agricultural Climate (CLAC), Agriculture Research Center, Ministry of Agriculture and Land Reclamation, Dokki, Giza, Egypt, during seasons of 2020 and 2021; summer seasons for molokhia and winter seasons for spinach. Two factors have been tested in both experiments; first factor was substrate type (50% perlite: 50% peat moss "S1" and 80% sand: 20% compost "S2") and the second factor was the fertilizing management programs (chemical nutrient solution whole season "CNS", chemical nutrient solution then compost tea for 5 days before harvest "CNS+5", chemical nutrient solution then compost tea for 10 days before harvest "CNS+10" and organic nutrient solution whole season “compost tea”"CT"). Results indicated the following: regarding the effect of substrate type, S1 could be cosidered the more suitable substrate for producing both molokhia and spinach with high yield and growth parameters. Regarding the effect of fertilizing management programs, CNS recorded higher yield and growth parmeters followed by CNS+5. On the other hand, CNS+5 recorded lower nitrate values than CNS. From the above mentioned results it could be sumarize that inspite of CNS recorded
the highist yield values but if we put nitrate content in consideration, the interaction between S1 and CNS+5 could be the most suitable formula between substrate type and fertilizing management programs for producing both molokhia and spinach with high yield and lower nitrate accumaltion than using the standerd chemical solution only the whole production season.