Nitrogen Release Characteristics And Effects Of The Coated Slow-release Fertilizer On Yield And Quality Of Cabbage

In China,low utilization of common fertilizers not only causes a waste of resources,but also leads to serious environmental pollution.Special controlled release fertilizers can improve the nitrogen use efficiency and reduce environmental pollution due to nutrient release synchronizing with crop uptake and low loss of ammonia volatilization.In this research,according to the fertilizer requirement characteristics of cabbage,"ventilation method" under laboratory conditions was adopted to study the volatilization rate and accumulation characteristics of Cabbage coated slow-release fertilizer.In addition,pot experiments and field experiments were conducted to study the effects of the coated slow-release fertilizer on yield,quality and NPKS content of soil and cabbage.The main results are as follows:(1)The volatilization rate and accumulation volatilization of ammonia reduced by special coated slow-release fertilizers.The dynamic changes of ammonia volatilization rate and accumulation volatilization of ammonia increased first,reaching up to the maximum and then decreased,and stabilized gradually(except for CK).The ammonia volatilization rate and accumulation volatilization of ammonia in OCF and MCF treatments reached the peaks at seventh day,while the ammonia volatilization rate and accumulation volatilization of ammonia in MSRF,CSRF1 and CSRF2 treatments reached the peaks at thirtieth days;Compared to nitrogen accumulation amount of OCF,MCF and MSRF,the ammonia volatilization of two cabbage slow release fertilizer reduced by 49.11%,32.18%,16.80% and 43.54%,21.61%,11.23%,respectively.(2)The releasing characteristics of three nitrogen forms(ammonium nitrogen,nitrate nitrogen and total nitrogen)in special coated slow release fertilizers best fitted by the polynomial equation.Elovich equation,quadratic polynomial equations and cubic polynomial equation all fitted the release of ammonium nitrogen,nitrate nitrogen and total nitrogen in two Chinese cabbage special coated slow release fertilizers,and the best fitting was the polynomial equation(correlation coefficient R2 of ammonium nitrogen is 0.9878**-0.9978**;the correlation coefficient R2 of nitrate nitrogen is 0.9767**-0.9919**;the correlation coefficient R2 of total nitrogen is 0.9886**-0.9959**).(3)The yield of cabbage increased by special coated slow-release fertilizers.In pot experiment,dry weight of shoot and root,and dry weight of plant in cabbage at two kinds of coated slow release fertilizer treatments were significantly higher than those of other treatments.In field trials,the yield of cabbage in CSRF1 treatment was significantly higher than that of OCF,MCF and MSRF treatments by 16.84%,19.35%,13.28% and 10.53%,13.28% and 7.140%.(4)The quality of cabbage improved by special coated slow release fertilizers.The content of VC in two kinds of coated slow release fertilizers increased by 19.82%-40.74% and 7.510%-26.28% respectively compared to the other treatments;the content of amino acid in CSRF1 improved by 16.34% and 29.89%,respectively compared to OCF and MCF treatments;the content of reducing sugar in CSRF1 and CSRF2 treatment was higher 60.32%-267.9% and 10.65%-154.3% than that of other treatments.The lowest nitrate concentration was found in CSRF2 treatnent,and decreased by 0.5100%,9.350% and 4.660% respectively compared to OCF,MCF and MSRF treatments.(5)The concentrations and utilization of nitrogen,phosphorus and potassium in cabbage increased by special coated slow-release fertilizers.In the pot experiment,the highest concentrations of nitrogen,phosphorus and potassium in root,petiole or leaf were observed in two kinds of special coated slow-release fertilizer treatments.In the field experiment,root nitrogen concentrations in CSRF1 and CSRF2 treatments increased by 17.28%-31.16% and 5.160%-17.60% compared to the other treatments;the concentrations of phosphorus in leaves were in order of CSRF2> CSRF1> MSRF> MCF> OCF>CK,but no significant difference was observed;the highest concentrations of potassium in leaf was found in CSRF2 treatment,and followed by CSRF1 treatment.Leaf potassium concentrations in CSRF2 and CSRF1 treatments were higher by 3.980%-48.87% and 1.850%-45.83% than that of other treatments.The utilization of nitrogen in cabbage was in order of CSRF1>CSRF2>MSRF>MCF>OCF.The utilization of nitrogen in cabbage at CSRF1 and CSRF2 treatments,which were 41.28% and 36.46% respectively,increased by 14.22-24.82 percentage points(CSRF1)and 8.400-20.00 percentage points(CSRF2)compared to OCF,MCF and MSFR treatments.The highest utilization of phosphorus in cabbage was found in CSRF1 treatment,and followed by CSRF2 treatment,increased by 6.780-7.850 percentage points(CSRF1)and 5.830-6.900 percentage points(CSRF2)respectively compared to OCF,MC and MSRF treatment.The utilization of potassium in cabbage was in order of CSRF1>CSRF2>MSRF>MCF>OCF.The utilization of potassium in cabbage at CSRF1 and CSRF2 treatments increased by 5.190-11.30 percentage points(CSRF1)and 0.9500-6.060 percentage points(CSRF2)compared to other treatments.(6)Special coated slow release fertilizer can improve the soil microorganism quantity,increase the content of effective nitrogen,phosphorus and potassium in soil.The number of soil bacteria in two special coated slow release fertilizer treatments increased by 256.5%-811.1% and 360.9%-1077% respectively,compared to CK,OCF,MCF and MSRF treatments.The number of soil fungi in two coated slow release fertilizers decreased by 175.0%-425.0% and 161.0%-400.0% compared to CK,OCF,MCF and MSRF treatments.The numbers of soil actinomycetes in two coated slow release fertilizer treatments were significantly higher than that of CK,while no significant differences were found among two special coated slow release fertilizers and OCF.Soil available potassium content of CSRF1 and CSRF2 increased by 22.47%-68.24% and 22.47%-45.50% compared to the other treatments,and significant differences were found between two special coated slow release fertilizers(CSRF1 and CSRF2).(7)Compared with two coated slow release fertilizers(CSRF1 and CSRF2),CSRF1 was better than CSRF2 due to higher yield,quality,NPK utilization of cabbage,and soil available NPK content.