施用钾肥对温室黄瓜光合特性及产量的影响

通过温室田间试验,研究施K2O 0、240、480、720、960 kg/hm2等5个钾肥处理对津春3号黄瓜光合特性、产量、效益和品质的影响。结果表明,施K2O 720 kg/hm2时,黄瓜的净光合速率最高;施K2O 240 kg/hm2,黄瓜的叶面积和叶数最大。随着钾肥施用量增加,黄瓜的光合作用呈现先增高后降低的过程,钾肥量与黄瓜叶片净光合速率(Pn)的关系式为y=-4.160+4.5307x-0.6693x2,r=0.9470**。施钾肥能够提高叶绿素含量,钾肥量与叶绿素含量增量SPAD值关系式为y=-6.66+7.406x 8-0.97x2,r=0.9836**。施用钾肥对黄瓜的前期结瓜作用明显,前期施用钾肥,结瓜数量和产量增加显著。施用钾肥黄瓜增产14.7%～53.5%;施K2O 720 kg/hm2时,黄瓜产量和经济效益最高。施用钾肥使黄瓜提前结果,并延长了黄瓜的结果期。施用钾肥改善黄瓜品质,在K2O 240～720kg/hm2范围内,随着K2O量增加,黄瓜果实中可溶性糖含量、Vc含量逐渐增加,硝酸盐含量降低。

Effects of potassium fertilization on photosynthetic characteristics and yield of cucumber in solar greenhouse

The effects of potassium fertilization on photosynthetic characteristics, yield, economic benefit and quality of cucumber(Jinchun 3)were studied in the solar greenhouse. There were five levels of potassium fertilization, K₂O 0, 240, 480, 720 and 960 kg/ha. The results showed that the net photosynthetic rate is highest under the level of K₂O 720 kg/ha, while the area and number of leaves are the largest under the level of K₂O 240 kg/ha. With the increasing of potassium application rate, photosynthesis of cucumber is increased at first then decreased, and the equation between K rate and net photosynthetic rate is y=-4.160+4.5307x-0.6693x2 (r=0.9470**). The chlorophyll content is increased with the application of potassium fertilizer, and the relation model between chlorophyll ΔSPAD volume and the potassium fertilizer application rate is y=-6.66+7.406x 8-0.97x²(r=0.9836**). It is obvious that with the increasing of potassium fertilizer rate at the early stages, the yield is significantly increased from 14.7% to 53.5%. The highest yield and benefit of cucumber are under the K₂O 720 kg/ha fertilization. The fruit bearing stage of cucumber is advanced and prolonged by the fertilizer application, and the quality of cucumber is also improved. Contents of soluble sugar and vitamin C of fruits are increased under the K₂O 240-720 kg/ha fertilization, while, the nitrate contents are decreased.