Xiayu GUO，Zhiyong AI

Hunan Hybird Rice Research Center,Changsha 410125,China

Chemical fertilizer is a guarantee of crop yield growth and it is surveyed that the effect concerned takes up to about 40%[1].Nevertheless,excessive application and unbalance proportion havecaused severe soil problems,involving poor soil permeability,decreased fertilizer use rate,pollution on surface and ground water,and soils[2-3].Currently,there is an increasing concern about improving soil eco-environment and fertility and reducing chemical fertilizer’s pollution by applying microbial inoculum fertilizer[4].Different with traditional chemical and organic fertilizers,microbial inoculum fertilizer contains specific living microorganisms for agricultural production[5]and enhances the growth of crops by vital movement of microorganisms[6].

The research started since the 1950s on development of microbial inoculum fertilizer domestically[7],but researches available are much fewer on its application in super hybrid rice compared with vegetable,tea,and pasture.In order to improve yield of super hybrid rice,the research designed fertilizer effect test based on microbial inoculum fertilizer to explore the effects on growth and yield of super hybrid rice.

Materials and Methods

Test materials

Test site and crop varietiesThe test was conducted in an experimental base of Hunan Hybrid Rice Center with Liangyou No.959 (a super hybrid rice combination)as test materials and seeds were provided by Hunan Hybrid Rice Center,also.

Test fertilizersThe test fertilizers included common compound fertilizer,containing over 48% nutrients and 16% phosphorous, nitrogen and potassium,and HYT microbial inoculum fertilizer,which is one of product series of high-efficient microbial inocu-lum fertilizer promoted by Agrinos AS.

Test method

Farmland designThe test included four treatments,including treatment CK (traditional fertilizers),treatment 2 with traditional fertilizers and 6 750 g/hm2HYT microbial inoculum fertilizer(gradient),treatment 3 with traditional fertilizers and 4 500 g/hm2HYT microbial inoculum fertilizer(gradient),and treatment 4 with traditional fertilizer and 2 250 g/hm2HYT microbial inoculum fertilizer (gradient).Specifically,traditionalfertilizers included 210 kg/hm2pure nitrogen,40%,20%,30% and 10% base fertilizer,tillering fertilizer,ear fertilizer and granulated fertilizer;300 kg/hm2superphosphate was applied as phosphorus fertilizer and totally applied as base fertilizer;potassium fertilizers contained 150 kg/hm2potassium chloride,50% tillering fertilizer and 50% ear fertilizer.HYT microbial inoculum fertilizer was applied along with base fertilizer,tillering fertilizer,ear fertilizer and granular manure,respectively.Besides,the test was designed as per randomized block design and rice was covered with mulches and isolated with ridges.Every treatment was with three replications,and the test plot has an area of 48 m2.

Farmland managementRice was sown on May 17,2014 and cultivated with soft trays.Two seeds were sown in every hole and every test plot contained 900 trays/hm2,followed by transplanitng at 20 cm×30 cm and harvesting on October 10.In conclusion,farmland management was conducted as per high-yield cultivation.

Observation index and methodFor every treatment,10 clumps of rice were collected to observe seedling growth and leafage.Besides,5 clumps of rice were sampled in mature stage from every test plot to explore economic traits.In addition,rice yields should be measured in different plots.The test data were analyzed with Microsoft Excel 2003 and DPS 6.05.

Results and Analysis

Effects of different treatments on tillering of super hybrid rice

As shown in Fig.1,the number of tillers was significantly higher in the treatment applied with microbial inoculum fertilizer than that of the control and reached the peak on July 19.For example,the number of tiller averaged 26.7 in treatment 3,which was 2.4 more than that of the control.Besides,the tillering rates were 58.9%,60.3% and 56.1% in treatments 2,3 and 4,respectively,and the final numbers of ear were 15.1,16.1 and 14.2,accordingly,keeping higher than that of the control,also.In general,tillering effective proved the best in treatment 3 where rice grew faster,with a higher ear rate.

Effects of different treatments on economic traits of super hybrid rice

As shown in Table 1,the number of effective ear was significantly higher in the treatment applied with microbial inoculum fertilizer than that of the control and the numbers were 11.05% and 8.57% higher in treatments 3 and 2 than that of the control.In treatment 4,the number of effective ear was 2.83% more than the control,showing significant differences.As for the number of seed per ear,treatment 4 achieved the most at 231.5,which was 13.7 more than that of the control,showing significant differences,and insignificant differences were shown between treatment 2 and the control,and between treatment 3 and the control.Besides,the number of practical seed number all exceeded 190 seed/ear in treatments 2-4,which was significantly higher than that of the control,but insignificant differences were shown among treatments 2-4.In addition,setting rate was the highest at 88.2% in treatment 2,significantly higher than that of the control and showing significant differences with treatments 3 and 4.Compared with the control,thousand-seed weight also improved in treatments 2-4,which kept 0.4,0.3 and 0.3 g higher than that of the control.In conclusion,microbial inoculum fertilizer has active effects on yield components of super hybrid rice,especially for increasing the number of effective ear and broadening rice storage capacity.

Effects of different treatments on yields of super hybrid rice

In the test,rice was harvested on October 10.It is notable that rice harvesting and husking proceeded alone in different test plots.After sunning and cleaning,the rice yield and significance analysis were recorded(Table 2).It can be concluded from Table 2 that yields from high to low were treatment 3＞treatment 2＞treatment 4 and treatment 1 (CK);yield of treatment 3 increased by 10.3% compared with the control,showing extremely significant differences;yield of treatment 2 increased by 6.2%,showing significant differences;yield of treatment 4 increased by 1.5%,showing insignificant differences.

Table 1 Effects of treatments on yield components

Table 2 Comparisons among treatments

Conclusion and Discussion

In the test,microbial inoculum fertilizer played a key role in increasing yield of super hybrid rice,so that yields of relevant treatments were all higher than that of the control.It is analyzed that it is microbe that contributes to rice growth.Many researches available have demonstrated that beneficial microorganism increases dramatically when some microbial fertilizer is applied,which enhances the content of available nutrients in soils and advances vitamin synthesis.Meanwhile,microorganisms would also produce plant hormone like substances,regulating plant growth and improving environment[8-9].In terms of super hybrid rice,the number of effective ear and seed per ear kept increasing,as well as thousand-seed weight,laying foundation for high yielding of rice.

The test designed three gradients on fertilizer quantity,including 2 250,4 500 and 6 750 g/hm2,of which the treatment with 4 500 g/hm2fertilizers proved the best,for the yield was extremely higher than that of the control.As for the treatment with 6 750 g/hm2,nutrients required by rice,such as phosphorus,nitrogen and potassium were excessive,because the test farmlands are located in demonstration farmlands of Hunan Hybrid Rice Center,featured by high soil fertility.Meanwhile,microbial inoculum fertilizer is able to transform the required nutrient elements to rice roots by microbial strains themselves.Consequently,nutrient enrichment occurs with abundant nutrients,which is adverse for rice growth.Therefore,the advantage of microbial inoculum fertilizer is not fully exploited.In addition,yield growth was small in the treatment with 2 250 g/hm2fertilizers,because it is hardly for the optimal result be achieved with lower dose of the fertilizer.

The research has investigated the effects of microbial inoculum fertilizer on growth and yield of super hybrid rice and the results showed that microbial inoculum fertilizer is of great value in planting for super hybrid rice.In future,it is recommended to further explore the optimal quantity,term and application method of microbial inoculum fertilizer in growth and development process of super hybrid rice.

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