滴灌与施肥对河西灌区紫花苜蓿光合生理特性和干物质量的影响

Effects of drip irrigation and fertilization on photo⁃ synthetic physiological characteristics and the amount of dry matter of alfalfa in Hexi Irrigation Area

摘要:

为探明不同滴灌量下施肥模式对紫花苜蓿光合特性和干物质量的影响，本研究设置 3 种滴灌量(I3：160 mm；I2：80 mm；I1：0 mm)和 6 种施肥模式(F1：磷 120 kg/hm² +氮 75 kg/hm² ；F2：磷 60 kg/hm² +氮 75 kg/hm² ；F3：不施磷+氮 75 kg/hm² ；F4：磷 120 kg/hm² +不施氮；F5：磷 60 kg/hm² +不施氮；F6：不施氮磷)，于 2020 年在河西灌区开展田间试验。结果表明：1)I3 处理下各茬次紫花苜蓿的株高显著高于 I1，较 I1 分别提高了 23. 02%、28. 69% 和 19. 63%，F1 的各茬次紫花苜蓿单株总干物质量显著高于 F6，分别是 F6 的 4. 27、3. 44 和 4. 96 倍。2)I3 处理下紫花苜蓿的叶绿素 a、b 含量、类胡萝卜素含量和叶绿素总含量高于 I2 和 I1，施肥处理下，F2 的平均叶绿素含量最高。3)I3F1 的净光合速率、 蒸腾速率、气孔导度和胞间 CO₂浓度显著高于 I1F6，所有处理中，I3F1 的紫花苜蓿单株根、茎、叶及总干物质量均获得最大值。综上，I3F1 是提升紫花苜蓿光合性能和干物质量的适宜栽培模式。

Abstract:

In order to explore the effects of fertilization patterns on photosynthetic characteristics and dry matter mass of alfalfa(Medicago sativa)under different drip irrigation rates，the field study was carried out in Hexi Irriga- tion Area in 2020. In the field study tree drip irrigation levels(I3：160 mm；I2：80 mm；I1：0 mm)and six kinds of fertilization mode(F1：phosphorus application 120 kg/hm² and nitrogen application 75 kg/hm² ；F2：phosphorus ap- plication 60 kg/hm² and nitrogen application 75 kg/hm² ；F3：no phosphorus and 75 kg/hm² nitrogen；F4：120 kg/ hm² phosphorus and no nitrogen；F5：60 kg/hm² phosphorus and no nitrogen；F6：no Apply nitrogen and phospho- rus)were set. The study showed that：1)The plant height of alfalfa under I3 was significantly higher than that of I1， which was increased by 23. 02%，28. 69% and 19. 63%，respectively. The total dry matter weight per plant of al- falfa under F1 was significantly higher than that of F6，which was 4. 27，3. 44 and 4. 96 times of F6，respectively. 2)The chlorophyll a，b content，carotenoid content and total chlorophyll content of alfalfa under I3 treatment were higher than those under I2 and I1. The average chlorophyll content of F2 was the highest under fertilization treat- ment. 3)The net photosynthetic rate(P_n)，transpiration rate(T_r )，stomatal conductance(G_s )and intercellular CO₂ concentration(C_i) of I3F1 are significantly higher than that of I1F6. In all treatments，the individual roots， stems，leaves and the amount of dry matter of alfalfa achieved the maximum value in I3F1. To summarize，I3F1 is a suitable cultivation model to improve the photosynthetic performance and dry matter quality of alfalfa.