Effects Of Organic Fertilizer Equivalent Substitution And Compound Fertilizer Reduction On Yield,Quality And Soil Active Substances Of Intercropping Potato

To explore the effect of organic fertilizer on compound fertilizer effect,an efficient and economical fertilization scheme was obtained.In this study,the input costs of high,medium and low fertilizers were set in the potato monocropping and potato-maize 2:2,respectively.Under the certain condition of fertilizer input costs,the application amount of two kinds of fertilizer will be adjusted in equal gradients according to the factory unit price of the fertilizer.A randomized block design was used to study the development of potato organs,photosynthetic physiology,nitrogen and phosphorus potassium absorption and utilization,potato yield and yield components,nutrient quality of tubers,and soil microbiological characteristics of potato rhizosphere,and the law of soil enzyme activity when organic compound equivalent compound fertilizer is used.The main conclusions are as follows:1)Effect on potato yield and qualityWhen the amount of potato compound fertilizer per hectare reached 750 kg and above,and between 750 kg and 1125 kg in the intercropping,750 kg of organic fertilizer was used instead of 375 kg compound fertilizer,potato yield was not decreased in monoculture,and increased in intercropping,the soluble protein content,ascorbic acid content,starch content and commercial potato rate of potato in single cropping and intercropping potato can reach the best value.In Beibei,Wuxi and Wulong,the highest net income of monoculture potatoes per hectare was 51188.33 yuan,55521.13 yuan and11575.8 yuan respectively and of intercropping potatoes per hectare was 34296.13 yuan?54078.53 yuan?23733.73 yuan.2)The effect on the growth of potato organsA sufficient amount of single compound fertilizer or combined application with organic fertilizer is an effective measure to maintain or increase the potato leaf area and leaf chlorophyll content.Organic fertilizer completely replaces compound fertilizer is not conducive to the increase of potato leaf area and leaf chlorophyll content.All compound fertilizer and organic fertilizer partially replaced compound fertilizer to increase the root activity of monocropping potato.In the intercropping potato,compound fertilizer is too high will significantly reduce the activity of potato root system.The application amount of compound fertilizer should be below 1500 kg/hm²,and it should be applied with organic fertilizer.When high-cost organic fertilizer is used instead of compound fertilizer,the potato root system also has relatively high activity.The large amount of fertilizer input is beneficial to the accumulation of dry matter in all organs in monocropping potato and the stems,leaves,and roots in intercropping potato.The partial replacement of compound fertilizer by organic fertilizer can significantly increase the dry matter accumulation of potato tuber.Low-cost fertilizer inputs are more effective than high costs in promoting the advancement of potato dry matter to the underground.3)Effects on Photosynthetic Physiology of potatoIncreasing the amount of compound fertilizer can increase the net photosynthetic rate and transpiration rate in monocropping potato leaves.Excessive compound fertilizer has no significant effect on the net photosynthetic rate of the upper leaves in the intercropping potato,but it significantly reduces the net photosynthetic rate of the middle and lower leaves.The combination of compound fertilizer with organic fertilizer or low-level compound fertilizer significantly increased leaf transpiration rate.All organic fertilizer treatments were unfavorable for the net photosynthetic rate and transpiration rate of the leaves in different parts of the two patterns.The intercellular CO₂ concentration in monocropping potato leaves decreased with the increase of compound fertilizer input.Organic fertilizer completely replaced compound fertilizer or no fertilizer treatment could increase intercellular CO₂ concentration in potato leaves.The intercellular CO₂ concentration in the upper leaves increased with the increase of organic fertilizer dosage at the same fertilizer cost in the intercropping potato.The intercellular CO₂ concentration in the middle and lower leaves increased with the increase of the organic fertilizer dosage at high-cost fertilizer input.When the fertilizer cost is input,it will increase first and then decrease with the increase of organic fertilizer dosage.The stomatal conductance of leaves of different parts in monocropping potato gradually decreased with the reduction of the input of compound fertilizer?or the increase of the input amount of organic fertilizer?.Under the same fertilizer input costs in potato intercropping,there was no significant difference in the stomatal conductance of potato leaves when compound fertilizer was applied.All organic or nonfertilizing treatments in the two modes of potato could effectively reduce stomatal conductance in potato leaves.4)Effect on absorption and utilization efficiency of nitrogen,phosphorus and potassiumIn monocropping potato,increasing the input of compound fertilizer can promote the absorption and utilization of nitrogen and potassium in potato.Increasing organic fertilizer can promote the absorption and utilization of phosphorus by potato.The excessive application of compound fertilizer in the intercropping potato will reduce the absorption and utilization of nitrogen,phosphorus and potassium in the potato.Rationally increasing the application amount of the compound fertilizer can effectively promote the absorption and utilization of nitrogen and potassium by the potato.Increasing organic fertilizer can promote the absorption and utilization of phosphorus by the potato.The contribution rate of fertilizer in monocropping potato gradually decreased with the decrease of compound fertilizer application amount,and the input of compound fertilizer which was too high or too low in the intercropping system would reduce the contribution rate of fertilizer.Under the same fertilizer cost in the two planting systems,organic fertilizers have the lowest contribution rate when they completely replace compound fertilizers,and the contribution rate decrease with increasing dosage.The application of compound fertilizer combined with organic fertilizer in a certain range can significantly increase the contribution rate of fertilizer to potato yield.5)Effects on rhizosphere microbial biomass of potato and soil enzyme activityApplication of fertilization especially organic fertilizer,has a significant effect on potato rhizosphere microbial population.A large amount of organic fertilizer can effectively promote the increase of bacteria and actinomycetes,but it is not conducive to the reproduction of fungi.At the same fertilizer cost,all application of compound fertilizer is not conducive to the reproduction of the three types of microorganisms.Fertilization can promote rhizosphere microbial biomass carbon and nitrogen in monocropping and intercropping potato.The partial replacement of compound fertilizer by appropriate amount of organic fertilizer is most beneficial to the increase of rhizosphere microbial biomass carbon,nitrogen in monocropping potato and rhizosphere microbial biomass nitrogen in intercropping potato.In the intercropping potato,the amount of microbial biomass carbon increased with the increase of organic fertilizer substitution,and it was the highest when all the organic fertilizers were replaced.Intercropping is more conducive to potato rhizosphere microbial reproduction and increase in microbial carbon and nitrogen.Fertilization can increase soil urease activity,and the effect is best when a certain amount of organic fertilizer is equivalent substitution to compound fertilizer.The results showed that the application of a small amount of compound fertilizer combined with a large amount of organic fertilizer or total organic fertilizer in monocropping potato significantly improved the growth environment of potato.The more organic fertilizer used in intercropping potato,the more beneficial potato soil rhizosphere environment improved.