不同遮阴处理下施肥对水稻生长及生理特性的影响

太阳辐射减弱是气候变化的重要特征之一，研究太阳辐射减弱对水稻生产的影响，探讨通过施肥能否减缓太阳辐射减弱对水稻生长及生理代谢影响，具有重要的生产实际意义。采用田间模拟试验探讨了不同生育期遮阴条件下施用复合肥和施用硅肥对水稻生长和光合生理特性的影响。采用3因素3水平正交试验设计，遮阴设3水平，即不遮阴（S0，遮阴率为0）、开花-成熟期遮阴（S1，遮阴率为64%）和分蘖-成熟期遮阴（S2，遮阴率为64%）；施用复合肥（N-P₂O₅-K₂O）设3水平，即100（F1）、200 kg·hm^-2（F2）和300 kg·hm^-2（F3）；施用硅肥设3水平，即不施硅（R0）、钢渣200 kg·hm^-2（R1）和钢渣400 kg·hm^-2（R2）。结果表明，遮阴降低水稻株高、叶面积指数（LAI）和胞间CO₂浓度（Ci），降低产量。与S0对比，S1、S2分别降低产量43.99%和54.24%。S1增加净光合速率（Pn）、气孔导度（Gs）和蒸腾速率（Tr），降低叶绿素含量（SPAD值），S2则增加SAPD值和Tr，降低分蘖数、Pn和Gs；施用复合肥可提高水稻株高、分蘖数、SPAD值、Pn和Tr，降低Ci和Gs。与F1相比，F2处理下LAI降低10.13%，F3则增加12.13%。与F2相比，F3处理下株高、分蘖数、SPAD值、Pn增加1.28%、8.21%、4.16%、7.64%，Tr则降低0.64%；施用硅肥可提高LAI、Pn、Gs和Tr，降低SPAD值和Ci。与R0相比，R1处理下株高和分蘖数减少1.27%和5.00%，R2处理下则增加0.50%和13.77%。研究认为，模拟太阳辐射减弱条件下，施用复合肥300 kg·hm^-2和硅肥400 kg·hm^-2，可有效减缓遮阴对水稻植株生长和光合作用的不利影响，保持较高产量。

Effects of fertilization on the growth and physiological characteristics of rice under different shading conditions

The weakening of solar radiation is one of the main issues associated with global climate change. It is of great practical importance to understand the effect of weakening solar radiation on rice production, and to explore whether fertilization can mitigate the depressive effects of weaker solar radiation on plant growth and physiological metabolism in rice. A field simulation experiment was performed to investigate the effects of compound fertilizer supply and silicate fertilization on the growth and photosynthetic physiological of rice. A black shading net was used to cover the plant canopy to simulate the weakened solar radiation. An orthogonal experimental design was adopted with three factors and three levels. Shading was set at three levels:no shading(S0, 0% shading rate), shading from flowering to maturity(S1, 64% shading rate), and shading from tillering to maturity(S2, 64% shading rate). NPK compound fertilizer was supplied at three levels:100(F1), 200 kg×hm^-2(F2), and 300 kg×hm^-2(F3), and silicate fertilization was also set at three levels:no silicate fertilizer (R0), slag fertilizer 200 kg×hm^-2(R1), and slag fertilizer 400 kg×hm^-2(R2). The results showed that shading decreased plant height, leaf area index(LAI), intercellular CO₂ concentration(Ci), and yield of rice. Compared with S0, the yields in the S1 and S2 treatments decreased by 43.99% and 54.24%, respectively. S1 increased tiller numbers, net photosynthetic rate(Pn), stomatal conductance(Gs), and transpiration rate(Tr), but decreased the SPAD value. S2 increased SAPD value and Tr, but decreased tiller numbers, Pn, and Gs compared to S0, while the NPK compound fertilizer supply increased plant height, tiller number, SPAD value, Pn, and Tr, but decreased Ci and Gs. Compared with F1, F2 decreased LAI by 10.13% and F3 increased LAI by 12.13%. Compared with F2, F3 increased plant height, tiller numbers, SPAD value, and Pn(by 1.28%, 8.21%, 4.16%, and 7.64%, respectively), and decreased Tr(0.64%), whereas silicate fertilization increased plant height, tiller numbers, LAI, Pn, Tr, and Gs, but decreased the SPAD value and Ci. Compared with R0, R1 decreased plant height and tiller numbers(1.27% and 5.00%, respectively), while R2 increased plant height and tiller numbers(0.50% and 13.77%, respectively). This study suggests that under reduced solar radiation, applying 300 kg·hm^-2 of compound fertilizer and 400 kg· hm^-2 of steel slag silicate fertilizer not only ensured higher yield but also clearly mitigated the depressive effects of decreased solar radiation on plant growth and physiological metabolism in rice.