Effects Of Irrigation, N And P Fertigation On The Yield And Quality Of Olive

Olive is one of the most important woody oil trees in the world,and olive oil has abundant health benefits for human.Reasonable cultivation techniques are important ways to improve the yield and adjust the quality of olive oil.Irrigation and fertilization are commonly used cultivation methods in olive production.At present,there are many studies on the effect of irrigation and fertilization on the yield and quality of olive oil in the harvest season,however,fewer comparative studies are focus on the whole production season.The study was conducted in consecutive years during 2014-2017 at Negba and Hoshaya under the Mediterranean climate（Israel）,and Xichang under the temperate climate with summer rain（China）.The irrigation strategies（rain-fed,flood irrigation and drip irrigation）,and amounts of irrigation water,N（0,75,150 and 300 kg/hm²）and P（0,100 and 200 kg/hm²）fertilizers were controlled.Both experiments of the irrigation strategies and the irrigation amounts in Hoshaya used variety‘Souri’with 6 and 11 years old,respectively,while the different fertilization（N,P）experiments in Negba adopted‘Barnea’with 7 years old.The characteristics of vegetative growth,reproductive growth,yield and quality of olive from flowering to harvest period were studied.The effects of irrigation,N and P fertigation on yield and quality of olive were revealed and the main results are as follows:1 Effects of irrigation on the growth and yield of oliveCompared with the olive trees without irrigation（CK）,the trunk diameter（TD）and shoot growth rose greatly,and the P and K contents in leaves,and K content in fruits,the numbers of inflorescences and flowers,perfect flower ratio and fruit setting increased significantly,which leaded to the significant increases of fruit quantity,yields of fruits and oil from trees under drip irrigation（DI）and flood irrigation（FI）.And DI had the best results of yields.The number of fruits from trees under FI increased from 255.77%to 335.02%,and the yield increased from 254.40%to 324.26%,respectively,and the oil yield increased from268.29%to 287.80%when compared to CK;while the fruits values from DI increased from103.65%to 125.50%,the yield increased from 103.49%to 110.85%,and the oil production increased from 88.05%to 90.07%in comparison with FI.Small amount of drip irrigation water（SDI）and large amount of drip irrigation water（LDI）were applied on olive trees.By comparing to the rain-fed trees（DI0）,the TD and shoot growth,leaf P and K contents,and fruit K content,the flowers and fruit setting increased significantly,causing the higher values of yields of fruits and oil from trees under SDI and LDI.And LDI had the best results of yields.The number of fruits from trees under SDI increased from 22.39%to 71.94%,and the yield increased from 39.16%to 84.75%,and the oil yield increased from 37.84%to 86.36%when compared to DI0;while the fruits values from LDI increased from 49.62%to53.29%,the yield increased from 61.01%to 63.07%,and the oil production increased from 53.92%to 59.35%in comparison with SDI.2 Effects of irrigation on the quality of olive leaf,fruit and oilCompared with CK,DI and FI significantly increased the content of UFA（OA,ALnA and PoA）,but significantly reduced the TPC of leaves,pulps and olive oil and improved the content of SFA（PA,SA,AA and BA）and FFA.The total content of UFA under DI was more than FI,while the TPC was lower.LDI and SDI significantly increased the content of UFA（OA,ALnA and PoA）,while reduced the TPC of leaves,pulps and olive oil and increased the contents of SA and FFA.The total content of UFA under SDI was fewer than LDI,while the TPC was more.3 Effects of applying N and P fertilizers on the growth and yield of oliveThe application of N and P fertilizers significantly increased the growth of TD and shoot,and the contents of N and P in leaves and fruits,the numbers of inflorescences and flowers,the perfect flower ratio and the fruit setting rate,thereby significantly increased the fruit quantity,yields of fruits and oil.The treatment of N and P with 207.14 and 145.68 kg/hm²per year had the best yields.4 Effects of applying N and P fertilizers on the quality of olive leaf,fruit and oilThe application of N fertilizer significantly increased the contents of PoA,LA and ALnA,but reduced the TPC in leaves,pulps and olive oil,and increased FFA.The content of FFA in oil from trees applying 300 kg/hm² of N per year was more than 0.8%,which was not meet the IOC’s trade standard of extra virgin olive oil.Applying 75 kg/hm² of N per year got better oil quality than that with the dose of 150 kg/hm² by increasing the TPC and OA contents.Applying P fertilizer significantly increased the content of UFA（OA and ALnA）,and reduced the content of SFA（SA,AA and BA）,but reduced the TPC in leaves and olive oil.An intermediate annual level of 84.09 kg of P₂O₅ per year got the highest TPC.The contents of FFA and the PV with increased fertilization rate of P₂O₅.In summary,drip irrigation before flower bud differentiation,and the period of flowering and fruit setting in Xichang insures high yield and quality.large amount of drip irrigation water during fruit development is recommended during olive development period in Israel.When high yield is the main target,it is best to applying 207.14 kg/hm² of N and 145.68kg/hm² of P₂O₅ per year,respectively.While the recommended application rates of N and P₂O₅ per year are 75.00 kg/hm² and 84.09 kg/hm² for producing high quality of olive and oil.