Effects Of Edible Fungus Residue On Rice Yield And Soil Fertility Under Paddy-edible Fungus Rotation System

With the rapid development of the industry of edible fungus production, vast amount of theedible fungus residue is generated. This would be a great threat to environment and resource wasteif it is not treated properly or reutilized. As a new ecological agriculture mode, rice-edible fungusrotation system could reuse the edible fungus residue by returning it to the field to play its value ofsoil building, which makes contribution to the rice production. In present study, a longterm fieldexperiment and incubation tests were conducted for revealing the effects of this measure. In thefield study, a combination of chemical fertilizers (C) and edible fungus residue (F) application wasset up. The rates of C and F (edible fungus residue) were set as0,50%and100%of conventionaldosage. By measuring the rice physiological indices and the nutrients in the rice plants and soil,investigations were carried out to reveal the effects of continuous application of edible fungusresidue on rice yield, nutrient absorption, the soil physicochemical properties, the balance ofnutrient in the soil and effectiveness of trace elements. The main results were as follows:(1) The combined application of C and F (C100F100) significantly improved rice growth, resultingin the maximum grain yield of8969kg/ha, being increased by62.69%compared with the controltreatment (C0F0). Spike number of single cluster, grain number of single spike and panicle lengthwere significantly increased under combined application of C and F, being the largest effectsreached by45.54%(C100F100),41.76%(C100F50),24.58%(C100F50), respectively, compared toC0F0.The effect of F on increasing rice grain yield was much less effective than C, but F couldalleviate the downward trend of rice economic coefficient compared to C.(2) After two years of rice-edible fungus rotation, a significant increase occurred in soil pH, beingthe highest increase of1.36pH units (C0F50). By contrast, soil organic matter (SOM) content andsoil available N, P and K decreased significantly, with largest decline being20.21%(C50F0),22.65%(C100F50),49.13%(C50F50),45.77%(C100F50) respectively. During fungus cultivationperiod, SOM content decreased significantly, while pH value, soil available P and K increasedsignificantly.The combined application of C and F contributed to optimize the transformation offertilizer in the soil. Although chemical fertilizer promoted rice production, it existed the risk of soil K deficit under its long-term single application, which could be avoided by combinedapplication.(3) The highest increase of total accumulation of N, P, K by rice aboveground were128.91%(C100F50),61.90%(C100F50) and206.10%(C100F100). With the continuation of the trial period, therole of chemical fertilizers and edible fungus residue gradually become apparently. Continuouslynone or significantly less (halved) fertilizers application caused serious soil nutrient deficiency,poor soil structure and declined soil fertility. Even halved chemical fertilizers combined with50%edible fungus residue could not meet the demand of rice growth.(4) Under the premise of chemical fertilizers, soil available Fe, Mn content decreased along withedible fungus residue addition, while soil available Cu, and Zn contents were not affectedsignificantly by edible fungus residue. Chemical fertilizer significantly promoted the rice toabsorb Fe, Mn, Cu, Zn, but edible fungus residue was not conducive to trace elementsaccumulation by rice aboveground.(5) In the incubation experiment, it existed significantly positive interaction between edible fungusresidue and urea on WSOC, and CNF20reached the highest value. NH4+-N concentration of soilsolution were up to the highest value by day15, and had a significant positive correlation with therates of edible fungus residue and urea. Under flooded state, applying high rate of edible fungusresidue had a negative role for the soil Fe activation, while it was opposite for Mn. Edible fungusresidue had inactivation effect on soil Cu, but not apparently on Zn.In summary, it’s necessary to optimize land management in fungus operation period andproportion of organic and inorganic fertilizers application in rice cultivation period. Propercoordination of organic-inorganic fertilizers ratio can promote the sustainable production of thepaddy soil. Combine application of C and F could ease the problem of soil degradation caused bylong-term application of chemical fertilizers. Meanwhile, it was also an effective pathway torecycle the waste from edible fungus production.