Effects of organic and chemical fertilizers on yield and quality in Hayward variety of kiwifruit

Evaluation of the possibility of integrated use of organic and inorganic fertilizers or gradual replacement of chemical fertilizers with organic manures is necessary in nutrition of kiwi vines, due to environmental issues resulted due to application of chemical fertilizers as well as increasing market value of organic fruits. This research was conducted to evaluate the short-term effects of four types of organic manures as compared to complete chemical fertilizer on total yield, yield components and qualitative characteristics in kiwifruit.
This short term field research was conducted in a randomized complete blocks design, consisting 6 treatments (complete chemical fertilizer treatment, organic manure treatments includes 30 kg of azola or azocompost or vermicompost or cow manure and treatment witout addition) and 4 replications, in kiwifruit garden, in citruse research center, Ramsar, Iran. Manures or fertilizers were mixd with surface soil, thoroughly and weed control and drop irrigation was done when nessesary. Fruits were harvested after ripening and their qualitative and quantitative properties were determined.
The results approved that quantitative parameters including total yield per tree, marketable fruits and its percentage and percentage of fruit dry matter, in organic and inorganic treatments were greater than control. Maximum and minimum total fruit yeild amoung treated plants were obtained in azocompost (84kg) and azola (62 kg) treatments. Minimum and maximum weight of tiny fruits in vermicompost (1kg) and azola (18kg), Minimum and maximum weight of deformed fruits in vermicompost and cow manure, minimum and maximum weight of unmarketable fruits in vermicompost (5 kg) and cow manure (28 kg), were obtained, respectively. Highest and lowest amount of marketable fruits produced by vermi/azocompost (58 kg) and azola (36kg) treatments, respectively. Ther is no significant differences between qualitative parameters in fruits in harvest time in different treatments such as firmness and total soluble solid (TSS). Acidity of fruits extract (pH) in vines treated with organic source were similar to control but it is more than chemical treatment, however there is no significant differences between treatments.Titratable acidity (TA) and Vitamin C in plants treated with organic or chemical fertilizer were greater than control, significantly.
according to the results in this research, it can be concluded that in the case of quantitative parameters, application of organic and inorganic fertilizers had positive but similar effects on total yield and marketable fruit weight, in harvest time as compar to the control, so, organic manure can be applied instead of chemical fertilizer in kiwifruit gardens and amoung organic manures, azocompost and vermicompost simes to be better choice. Due to environmental issues of chemical fertilizers, available organic manures including vermicompost, azocompost and cow manure can be applied to increase the quantitative and qualitative parameters and to produce organic kiwifruit in north of Iran.