Effects Of Water Hyacinth Organic Fertilizer On Yield Of Double-cropping Rice And Physio-ecological Properties Of Paddy Field

In this research,seven different combined application proportions of water hyacinth and nitrogen fertilizer had been designed,they were: T1(0 percent nitrogen fertilizer and 0percent water hyacinth),T2(100 percent nitrogen fertilizer and 0 percent water hyacinth),T3(80 percent nitrogen fertilizer and 20 percent water hyacinth),T4(60 percent nitrogen fertilizer and 40 percent water hyacinth),T5(40 percent nitrogen fertilizer and 60 percent water hyacinth),T6(20 percent nitrogen fertilizer and 80 percent water hyacinth)and T7(0 percent nitrogen fertilizer and 100 percent water hyacinth).The conventional early rice-double cropping late rice fertilization mode(T2)was used as control.The effects of different proportions of water hyacinth and nitrogen fertilizer on rice population quality,rice yield,rice quality,physicochemical properties of paddy soils and greenhouse gas emissions were researched,this would provide theoretical basis for a complete set of high yield and good quality rice fertilization measures after returning water hyacinth,optimized management of paddy soil nutrient,greenhouse gas emissions and control of agricultural non-point source pollution.The following conclusions have been drawn in this study:1 The effect of different combined application proportions of water hyacinth and nitrogen fertilizer on double cropping rice population quality Combined application of water hyacinth and nitrogen fertilizer played a significantly promoting role on rice tillers.The tiller number of T2 was high in previous tillering stage,but the tiller number of T3,T4,T5 and T6 were more at top tillering,and there was no significant difference between these treatments.About the plant height of double cropping rice,T4 was the highest,followed by T5,T3,T2,T6,T1 and T7.Appropriate proportion of water hyacinth and nitrogen fertilizer could promote nutrient absorption of rice,thereby promoted the above-ground portion of rice,and plant height had increased.The SPAD value of T4 in early or late rice was the maximal,it could be explained that combined application proportion of T4 could promote the synthesis of chlorophy effectively,and enhanced photosynthesis of rice leaves.Dry matter accumulations of T1,T2 and T7 were all significantly lower than that of T4,T5,T3 and T6,this result showed that combined application of water hyacinth and nitrogen fertilizer was beneficial to increasing dry matter accumulation of rice.Combined application of water hyacinth and nitrogen fertilizer could also help to improve LAI value of rice leaves,enhance photosynthesis,delay plant senescence and increase production of rice.2 The effect of different combined application proportions of water hyacinth and nitrogen fertilizer on yield components,yield and quality of double cropping rice Considering the year production of double cropping rice,rice production of T4,T3 and T5 were all increased compared with T2,and effect of T4 increasing production was the greatest,about 6.53% yearly increase.But there was no increase either in T6 or T7.The rates of brown rice,white rice rate and whole polished rice of T4 in both early and late rice were all the highest.The variation trend of chalk white rate in early rice and late rice were similar,and T4 was the least,they were 13.4% and 14.3% respectively.There was no significant difference between T3,T4 and T5,and they were less than T2.Chalk white rates of T7 and T1 had significant difference with others.The highest protein content in early and late rice were all T4 and content of T3,T5 and T6 were all higher than T2,but no significant difference.The lowest straight-chain starch content in early and late rice were T4,T1 was the highest.In early rice,straight-chain starch content of T3 and T5 were lower than T2,and in late rice,T3,T5 and T6 were lower compared with T2.Combined application of water hyacinth and nitrogen fertilizer could increase rice yield,and improve the quality of rice.3 The effect of different combined application proportions of water hyacinth and nitrogen fertilizer on physicochemical properties of paddy soils The soil p H of each treatment in early and late rice fields presented a certain volatility,but not obvious.The soil p H in early rice field ranged from 6.31 to 7.11.It was greater than T2 in T3,T1,T4,T7,T5 and T6 during different periods,but it remained unchanged in T1.About soil p H in late rice fields,T2 showed a linear decrease,and it was less than other treatments significantly.There was no obvious difference between T6 and T7,but they were higher than others.In mature stage,soil bulk densities in late rice fields were greater than early rice,and they were all presented: T1 > T2 > T3 > T4 > T5 > T6 > T7,in addition,it was greater in the mature stage than the period before transplanting.The soil porosity in early rice fields were characterized T7 > T6 > T5 > T4 > T3 > T2 > T1,in late rice,it presented T7 > T6 > T5 > T4 > T3 > T1 > T2.The contents of soil total nitrogen(TN)were characterized by T2 > T3 > T4 > T5 > T6 > T7 > T1 after harvest of early and late rice.Combined application of water hyacinth and nitrogen fertilizer led to decreasing of TN,the higher proportion of water hyacinth,the lower total nitrogen(TN)content.Appropriate proportion of water hyacinth and nitrogen fertilizer application increased the content of soil organic carbon(SOC).After harvest,the contents were characterized by T7 > T6 > T5 >T4 > T3 > T2 > T1,the higher ratios of water hyacinth,such as T6 and T7,the moresignificant influence on soil organic carbon(SOC)content.4 The effect of different combined application proportions of water hyacinth and nitrogen fertilizer on greenhouse gas emissions The seasonal emission rule of CO2 emission fluxes of every treatment in early rice paddy was consistent with each other during growth period.The trend reduced firstly and then induced,the emission was the maximum at grain filling stage.The order of CO2 emissions of each treatment was: T4> T5> T2> T3> T6> T7> T1.The rule of CO2 emission fluxes of each treatment in late rice paddy was also consistent.It increased firstly and then decreased.The order was: T4> T2> T5> T3> T6> T7> T1.CH4 fluxes of each treatment in early rice paddy on May 19 th showed T2> T3> T4> T6> T5> T7> T1.There was a significant CH4 fluxes increase in T4 at booting stage,the CH4 emissions order was T4> T6> T5> T3> T2> T1> T7.CH4 emission fluxes in late rice paddy showed centralized,high intensity and short duration when paddy was flooding,the emission fluxes died-off at field drying period.The CH4 emissions in each treatment showed T4> T6> T5> T3> T2>T7> T1.The emission trends of N2 O emission flux in early rice treatments were basically the same,the N2 O emissions stayed a low level in flooding period,sources and sinks changed alternately.After drying fields,paddy soil became source of N2 O.N2O emissions of each treatment showed T4> T5> T2> T6> T3> T1> T7.There was no regular performance in N2 O emission fluxes of different late rice treatments.N2 O emission flux of T2,T3,T4,T5 and T7 reached a peak value on September 5th.N2 O emissions of each treatment showed T4> T7> T5> T3> T2> T6> T1.