| The fertilizer utilization rate of japonica rice in China is much lower than that in developed countries and it is predicted to decrease further.The high cost of traditional fractional fertilization method,low fertilization efficiency and utilization rate conteractes the role of nitrogen fertilizer in increasing crop production.The deep side fertilization technology combined with the slow-release fertilizer increased japonica rice production and the nitrogen fertilizer utilization.The effect of slow release rate fertilizers on crop production varies as they have different composition and physiochemical characteristics.The study presented here aims to explore the effects of releasing characteristics of different slow release fertilizer on the growth,yield formation and nutrient absorption,and utilization characteristics of japonica rice in cold regions.This paper exploreded a theoretical basis for the reasonable application of slow-release fertilizers in the cold one-time lateral deep application.We set up several experiments field experiment to investigate the effect of one-time machine-inserted deep and controlled release fertilizer on the growth,nutrient accumulation and yield of japonica rice.In 2018-2019,the fertilization trial of the japonica rice was carried out in Beilin District,Suihua City,Heilongjiang Province.The tested japonica rice variety was Suijing 18.Fertilization treatments were set as:46%common blended compound fertilizer(CG),48%Japanese coated controlled release fertilizer(T1),52%domestic coated controlled release fertilizer(T2),48%domestic blend 5 treatments of coated controlled-release fertilizer(T3),52%domestic slow-release blending special fertilizer(T4).The main results obtained are presented as follows:1.The initial nitrogen nutrient release rate of T1 and T2 in static water culture were 5.66%and 6.02%respectively.This nitrogen nutrient releasing rate is comparable to the initial nitrogen nutrient release rate of slow-controlled release fertilizers in China.Therefore,T1 and T2 can be applied only once to support rice growth during its complete growth period,which is followed by T4 fertilizer.T3 treatment is characterized by a higher initial nitrogen nutrient releasing rate and shorter releasing period.The effect of one-time application of T3 during the growth period of japonica rice was worse than that of T1,T2 and T4 fertilizers.2.The one-time application of slow release fertilizer at the deep side can meet the nutrient requirements of japonica rice throughout the growth period,while the response of the absorption of nutrients in japonica to different slow-release fertilizers varies.The deep application of slow release fertilizer on the side of the machine can promote the early greening of rice seedlings compared to the conventional fertilization,and its'early nutrient release patterns matched the nutrient absorption law of japonica rice.The annual increase of percentage of available tiller was more than 6.70%in 2018 and 2.98%-6.35%in 2019.The dry matter accumulation in slow-release fertilizer treatments at the early stage of japonica rice growth was lower the conventional treatment.In the two-year trial,during jointing and booting stage,the accumulation of dry matter in the T1treatment were of 6.86%higher than the CG treatment and T2 treatment were of 5.82%higher than CG treatment.Compared to the CG treatment,the dry matter accumulation of T1 and T2treatments at maturity were increased by 1.38t/hm~2and 1.28t/hm~2,respectively.In the two-year trial,the storage capacity and harvest index of other application of slow and controlled release fertilizer treatment(with the exception of T3 treatment)were higher than that of CG treatment.The storage capacity was incresead by 17.99%and 7.57%in 2018 and 2019,respectively;The slow release fertilizer treatment harvest index was increased by an average of 8.99%and 28.22%in 2018 and 2019,respectively.The nitrogen nutrient release rates of fertilizers in the soil in the early stage of T1 and T2 treatment were slower than that of T3 treatment;The nitrogen nutrient releasing rates of fertilizers treated with CG and T3 in the early growth stage of japonica rice is higher than the actual nitrogen demand of japonica rice,which leads to japonica rice absorbing excess nitrogen when it is prior to the booting stage.The amount of nitrogen accumulated in CG and T3 during the early stage was highe.However,the nutrient supplies of CG and T3 treatments in the late stage of japonica rice growth were insufficient.This was supported by the higher nitrogen accumulation(over 6.69%)of japonica rice in T1 and T2 than that in CG treatments during the mature period.Application of slow-release fertilizer can promote the accumulation of phosphorus and potassium,improve nitrogen partial productivity,nitrogen agronomic utilization rate and nitrogen harvest index of japonica rice.In the two-year trial,the partial nitrogen productivity of T1,T2,T3 and T4 treatment was 10.57-38.82kg/kg higher than that of CG treatment and the nitrogen harvest index was 8.07%higher than that of CG treatment.Our data suggest that it is feasible to apply fertilization in one side deep in cold area japonica rice.Considering from the perspective of simultaneous nutrient absorption and utilization,T1 treatment is the best,followed by T2 treatment,followed by T4 treatment,and T3 treatment has the lowest fertilizer efficiency.3.Increasing the seed setting rate of japonica rice can increase the yield of japonica rice.The production of T1 and T2 fertilization treatments was significantly different from that of CG treatment in 2018.The production of T1 and T2 treatment was 14.34%and 11.26%higher than that of CG treatment,respectively.The production of T1 and T2 treatments were 2960.85kg/hm~2and 2373.75kg/hm~2higher than that of CG treatment in 2018 and 2019,respectively.Evaluating from the aspect of production,T1 was better than T2 treatment,followed by T4 treatment,and T3treatment had the lowest yield.Although the cost of slow-release fertilizers was relatively expensive.However,compared to the CG treatment,one-time application of slow-release fertilizer increases income by at least 80 yuan per mu,and reduce labor and save invests.Among the slow-release fertilizer treatments,T1 treatment had the best effect in enhancing income,followed by T2 treatment.The results of this study provided a reference for the selection of no-fed fertilizer varieties of japonica rice under reduced nitrogen conditions. |
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