The Effect Of Organic And Inorganic Fertilizer On Growth,Yield And Fruit Quality Of Cucumber Grown In 'Sandwich' Soilless Culture System

Cucumber?Cucumis Sativa L?is widely spread throughout the world and has been cultivated in greenhouses.The excess use of nitrogen fertilizers in agriculture lead to the accumulation of nitrates in the plants and groundwater,have ultimate negative impact on human health.Thus reduction of chemical fertilizers is required to reduce these hazards.So far,there is a paucity of information on the ratio of organic to inorganic fertilizer applied for vegetable production.Therefore,the aims of the current study are to determine the optimum depths of sand on water contents,optimal amount of organic base fertilizers in substrates,optimum ratio of poultry manure?PM?to mineral fertilizer MF?NPK15:15:15?,and the best ratio of NO₃^-/NH₄⁺in nutrient solution.Therefore,the experiments were conducted using troughs built by red bricks.The total depth of root zone?30 cm?was divided into three layers and the thickness of each layer was kept 10 cm.The top layer of trough was sand and used a cover,the middle layer was used for the treatments,mixture of fertilizer with substrate and the bottom layer was only substrate?cocopeat?.The trough system in this structure is called‘Sandwich'Culture System.The experimental design was randomized complete block design?RCBD?with three replicates.The main results were summarized as follows:1.Effect of Different Sand Thickness on Moisture and Temperature Changes in Substrate.The sand added to different depths of coverage?0,5,10,15,20 cm?represent the treatments?T1-control,T2,T3,T4,T5?respectively,the final treatment was plastic film mulch?T6?.T3 recorded the best treatment and exhibited the most stable moisture and temperature during the whole period of experiment;this result was used in the following trials.2.Effect of Different Amounts of Organic Manure on Cucumber Growth and Yield grown in Substrates.Five levels of organic manure were used,which were 15,30,45,60 and75 kg/m³ respectively.The organic manure was mixed with coco-peat based on the weight/volume?w/v?,for T1,T2,T3,T4and T5 respectively,in addition to nutrition solution as control?CK?.The results of this experiment showed that the treatments of organic manure had a positive effect on vegetative growth,fruit,and physiological parameters of cucumber plants.Organic manure at the rate of 60 kg/m³ had the best positive effect on the vegetative growth and fruits parameters in cucumber plant.3.Effect of Mixed Organic Manure with Inorganic Fertilizer on Growth,Yield,and Fruit Quality of Cucumber Grown in Soilless CultureAmount of poultry manure?PM?and mineral fertilizer MF?NPK15:15:15?were mixed with coco-peat based on the weight/volume?w/v?.The treatments of this experiment were as follows;60 kg PM?T1?in each cubic meter substrate used as a control,30 kg?PM?plus 3 kg MF?T2?,30 kg?PM?plus 5kg MF?T3?and 30 kg?PM?plus7 kg MF?T4?.The results demonstrated that integrated use of PM and mineral fertilizers MF)significantly improved?p<0.05?vegetative growth,physiological parameters and quality of the crop.Whereas,treatments T2,T3,and T4 did not differ among themselves.4.Effect of NO₃^--N/NH₄⁺-N Ratio on Cucumber Growth,Nitrogen Metabolism,Fruit Quality and Yield in Soilless Culture.Four nutrient solution treatments of nitrogen were applied,as a ratio of NO₃^--N to NH₄⁺-N,as follows:?T1?=100:0%,?T2?=75:25%,?T3?=50:50%,?T4?=25:75%.Total nitrogen concentration in all treatments was 196 mg/L.The results demonstrated that,the use of NO₃^--N combined with NH₄⁺-N?75:25;50:50%?had significantly?p<0.05?affect the vegetative growth,physiological,nitrogen-enzymes activities parameters,yield and cucumber fruits quality.Finally,we concluded that,the best thickness was 10 cm of sand layer,which was more feasible to maintain required moisture and temperature in substrate.Moreover,the optimal level of organic manure,60 kg/m³?poultry manure/substrate?,improved all the cucumber parameters growth,quality and yield components.The best application ratio was 30 kg?PM?mixed with 3 kg MF?NPK15:15:15?in each cubic meter substrate.Based on these results,the optimal combined ratio of 75:25%and50:50%?NO₃^--N/NH₄⁺-N?is chosen to improve cucumber performance under the condition of this this experiment.