施氮量对双季稻产量及其群体光合特性的影响

以早稻株两优4024、金优402和晚稻H优159、金优207为试材分析了不同施氮水平对双季稻(早稻、晚稻)产量及群体特性的影响。施氮水平设置为120,150,180,225 kg/hm2(分别记作N1、N2、N3、N4),考察各处理的产量及其形成和分蘖动态、剑叶SPAD值、剑叶光合速率以及干物质积累等变化指标。结果表明:早稻株两优4024、金优402和晚稻H优159、金优207各处理产量均呈N1、N4、N2、N3依次增加的变化趋势;4个供试组合在分蘖盛期的总生物量呈N1、N2、N3、N4依次增大的变化趋势,在齐穗后13 d、成熟期4个组合的总生物量均呈N1、N4、N2、N3依次增大的变化趋势;相关分析发现,齐穗后13 d、成熟期的叶干质量、茎鞘干质量、穗干质量、根系干质量、地上部干质量、生物总量和剑叶光合速率与产量之间均呈显著或极显著正相关。试验结果说明,在120~180 kg/hm2,增加施氮量有利于双季稻取得高产;增加施氮量可促进分蘖盛期干物质的积累,但过量施氮会影响生长后期干物质的积累;齐穗后较大的生物总量和较高的剑叶光合速率有利于双季稻取得高产。

Effects of Nitrogen Levels on Yield and Photosynthetic Characters of Double Cropping Rice

In this study,Zhuliangyou 4024 and Jinyou 402,two early rice combination and Hyou 159 and Jiny-ou 207,two late combination were employed for tested materials,the effects of different nitrogen levels on canopy ap-parent photosynthesis(CAP)and yield were studied.Nitrogen levels were set to N1 (120 kg/ha),N2 (150 kg/ha), N3 (180 kg/ha),N4 (225 kg/ha),the yield and its components,tiller dynamics,SPAD and photosynthetic rate of flag leaves and dry matter accumulation of different treatment were comprehensive survey.The results showed that the yield of early rice combination Zhuliangyou 4024 and Jinyou 402 and late rice combination Hyou 159 and Jinyou 207 were showed decreased from N3 ,N2 ,N4 to N1 in turn;The total biomass of the four combination were increased with the nitrogen levels,but after full heading,each treatments were showed decreased from N3 ,N2 ,N4 to N1 in turn;The results of correlation analysis showed that the dry weight of leaf,dry weight of stems and sheaths,dry weight of spike,dry weight of root,upside dry wight,total biomass,flag leaf photosynthetic rate after 13 d of heading stage and mature period had significant or very significant positive correlation with yield.Which indicated that increasing the a-mount of nitrogen was beneficial to obtain high yield of double cropping rice in the range of 120 -180 kg/ha,increas-ing the amount of nitrogen could promote the dry matter accumulation at tillering stage,but excessive nitrogen could influence the accumulation of dry matter at later growth stage,maintaining larger total biomass and higher photosyn-thetic rate of flag leaf after heading stage were the key measures to acquire high yield of double cropping rice.