| Heilongjiang,a large agricultural province,has always been concerned by researchers because of its special climate,soil characteristics and geographical location.Previous studies on paddy field in the black soil region of Heilongjiang province focused on the effects of different irrigation,fertilization and water and fertilizer coupling on rice growth,however there were few studies on physical mechanisms,especially solar radiation resources.Therefore,it is necessary to study the utilization of light-heat resources in the black soil region of Heilongjiang province,to provide theoretical basis and reference for improving the utilization efficiency of light-heat resources in paddy fields.Based on this,field experiments were conducted for four consec utive years on irrigation methods and fertilization management in this area.Experiment 1:five fertilization levels were set up which namely:inorganic nitrogen fertilizer(T1,110 kg/hm~2pure nitrogen),30%humic acid fertilizer+70%inorganic nitrogen fertilizer(T2),50%humic acid fertilizer+50%inorganic nitrogen fertilizer(T3),70%humic acid fertilizer+30%inorganic nitrogen fertilizer(T4)and humic acid(T5,1500 kg/hm~2).Experiment 2:Three irrigation methods were set up which namely:control irrigation(CI)and flood irrigation(FI)and wet irrigation(WI),the level of fertilization is the local level of fertilization.Experiment 3:different irrigation and fertilization methods were tested,the irrigation and fertilization were the same w ith experiment 1and experiment 2,the main result showed as follows:(1)At tillering stage,jointing stage,heading stage and ripening stage,the RUE(radiation use efficiency)increased firstly and then decreased.The lowest amount of effective radiation interception with different fertilization methods was obtained under the T2 condition,and its RUE of different growth stages and whole growth stages was also the lowest,while the RUE of T4 and T5 treatments was higher than that of other treatments.Under d ifferent irrigation methods,the amount of effective radiation interception in CI treatment was lowest.The RUE in FI treatment was higher than that of CI and WI treatments.The RUE at different growth stages and whole growth stages under CT4.CT5,FT4,FT5,WT4 and WT5 treatments were significantly higher than other treatments,while CT2,FT2 and WT2 treatments were significantly lower than other treatments.(2)The changes of canopy temperature in paddy fields with different treatments were different.The changes of canopy temperature during the whole growth period and different growth stages under different fertilization methods were not significant among T1,T2,T3,T4 and T5treatments.Under CI treatment the canopy temperature was higher than that of under FI and WI treatments,and all of them were lower than atmosphere temperature.The canopy temperature under CT2 and WT2 treatments was higher than that of other treatments,and there was a negative difference between the canopy and temperature during the whole growth period.The canopy temperature of CT2 and WT2 treatments was higher than those of other treatments,and there was no significant difference as compared to atmosphere temperature.(3)With the increase of soil depth,the soil temperature of paddy fields under different treatments decreased firstly and then increased,reaching the maximum at 5 cm and the lowest at15 cm.The soil temperature of 5 cm and 10 cm was significantly higher than that of 15 cm,20 cm and 25 cm,but there was no significant difference among 15 cm,20 cm and 25 cm.The soil temperature of 5 cm and 10 cm in T1,T2,T3,T4 and T5 treatments varied with different fertilization methods.The surface soil temperature of T2 treatment was higher than that of T1,T3,T4 and T5 treatments,followed by T1 and T3 treatments,and the soil temperature of T4 and T5treatments was the lowest.The soil temperature of 15 cm,20 cm and 25 cm had no significant difference among T1,T2,T3,T4 and T5 treatments.Under different irrigation methods,the soil temperature of 5 cm and 10 cm in CI treatment was significantly higher than that of in FI and WI treatments,but there was no significant difference among 15 cm,20 cm and 25 cm.The soil temperature of CT2 and WT2 treatment was higher than that of other water and fertilizer treatments.The surface soil temperature of CT4,CT5,FT4 and FT5 treatments was relatively small,but there was no significant difference among the soil temperature under different water and fertilizer treatments.(4)The plant height under T2 treatment was significantly lower than that under T1,T3,T4and T5 treatments at tillering stage,jointing stage and heading stage.The plant height of rice under CI treatment was lower than that of under FI and WI treatments,and at the jointing and heading stages was significant.The plant height under different water and fertilizer conditions had significant differences at tillering stage,jointing stage and heading stage.The lowest value was obtained in WT2 treatment,and the highest value was recorded in CT5 treatment.Dry matter and LAI(leaf area index)under FI,T5 and FT5 treatments were the largest in the two growing seasons,while under CI,T2 and WT2 treatments were the lowest.(5)SPAD(The chlorophyll content)of rice under different fertilization treatments,the best was for T5 treatment,and under CI treatment was higher than that of FI and WI treatments.SPAD under CT5 and FT5 treatments was higher than that of the other treatments.The fluorescence parameters under FI,T5 and CT5 treatments were better than those of CI,T2 and WT2 treatments.(6)Comparing the WUE_i(irrigation water use efficiency)and yield of rice under different irrigation and fertilization treatments,it was found that the WUE_i between different irrigation and fertilization treatments was small,but the WUE_i under different water and fertilizer coupling treatments changed greatly.The WUE_i under CT4 and CT5 treatments was the highest,above 1.8kg/m~3.In terms of yield,CT5 treatment had the highest yield in the two growing seasons.(7)In view of the effects of different water and fertilizer methods on paddy fields,6evaluation indexes,such as yield,WUE_i,RUE,extinction coefficient,dry matter and LAI were selected.The improved multi-objective decision making model based on game theory was used to evaluate the results.The evaluation results were ideal and consistent with reality.From the analysis and model assessment,under the control irrigation,1500 kg/hm~2 humic acid applied in the soil was the best treatment.Under this condition,the utilization of light-heat resources and the yield were the highest,as well as the irrigaton water use efficiency was increased with the decrease of irrigation water.Therefore,the control irrigation with the1500kg/hm~2 humic acid could be given full attention. |
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