不同氮处理对温室膜下滴灌甜瓜产量和品质的影响

Effects of different nitrogen treatments on yield and quality of greenhouse muskmelon under mulched drip irrigation condition

【目的】针对我国设施农业肥料利用效率偏低的现状,采用滴灌施肥技术,以甜瓜为试验材料,研究不同施氮量和施氮频率对甜瓜氮磷钾吸收量、产量和品质的影响,在保证甜瓜产量的前提条件下,减少化肥的施用量,达到提高肥料利用效率的目的。【方法】以甜瓜品种‘一品天下208’为试材,在温室内进行了覆膜滴灌种植试验。根据温室内收集的气象资料,应用Penman-Monteith修正公式确定灌水量,采用1.0ETc进行灌水。试验设置3个氮肥水平,85 (N_1)、125 (N_2)、160 kg/hm^2 (N_3);3个施氮频率,5 d (F_5)、10 d (F_(10))、15 d(F_(15)),共9个处理,完全随机区组设计。膨大期测定甜瓜叶片净光合速率,成熟期测定干物质累积量、氮磷钾吸收量、产量及品质。【结果】在同一施氮水平下,甜瓜净光合速率随施氮频率的增加而增大,高频次施氮处理(F_5)的净光合速率均大于中频次施氮处理(F_(10))和低频次施氮处理(F_(15)),平均增加了17.4%和56.1%。在同一施氮频率下,高氮处理(N_3)的叶片净光合速率均高于低氮处理(N_1)和中氮处理(N_2),平均增加了22.6%和9.8%。在低氮(N_1)和中氮(N_2)条件下,提高施氮频率能够促进甜瓜干物质累积及氮磷钾吸收量,而在高氮(N_3)条件下,F_5和F_(10)处理下的甜瓜产量差异不显著(P <0.05)。在相同施氮频率条件下,高氮处理(N_3)的产量为25.30 t/hm^2,均高于低氮处理(N_1)和中氮处理(N_2),平均增加了7.2%和0.4%,但是高氮(N_3)处理与中氮(N_2)处理间差异不显著(P> 0.05)。在同一施氮频率下,中氮处理(N_2)的果肉品质最佳,施氮量不足或者过量都不利于甜瓜品质的改善;在同一施氮水平下,中频次施氮处理(F_(10))下的果肉品质均高于高频次施氮处理(F_5)和低频次施氮处理(F_(15))。【结论】施氮量和施氮频率控制在125 kg/hm^2和10天时,甜瓜的品质最佳,产量略低于施氮量160 kg/hm^2和施氮频率5天。但从化肥减量和降低人工成本角度考虑,N_2F_(10)是最佳的处理组合。

【Objectives】The conventional soil fertilization is relatively low in fertilizer efficiency in crop production inside the facilities in China.The alternative drip irrigation-fertilization technology was applied in muskmelon planting,and the suitable nitrogen application amount and frequency were studied in this paper.【Methods】Muskmelons cultivar of YPTX208 was used as test materials in a mulched drip irrigation experiment inside greenhouse.The irrigation amount was determined using modified Penman-Monteith equation and 1.0ETc was adopted for irrigation.Three N levels of 85,125 and 160 kg/hm^2(N1,N2 and N3)and three N application frequencies of 5,10 and 15 days(F5,F10 and F15)were setup for the experiment.Leaf net photosynthetic rate was measured during the fruit enlargement period.The dry matter accumulation,nutrient absorption,fruit yield and quality of muskmelon were measured during the ripening period.【Results】At the same N level,the leaf net photosynthetic rate was the highest in frequency of F5,followed was F10 and F15,the average increase was 17.4%and 56.1%.At the same N application frequency,the leaf net photosynthetic rate in N3 was higher than in N1 and N2,the average increase was 22.6%and 9.8%.Under N1 and N2 rates,the higher N application frequency significantly promoted dry mass accumulation and NPK uptake of muskmelon;while under N3 rate,there was statistically significant difference in growth and NPK accumulation between F5 and F10.Under the same N application frequency,the yield of treatment N3 was 25.30 t/hm^2,which was significantly higher than that in treatment N1(P<0.05),but not than N2,the average increase was 7.2%and 0.4%.At the same N application frequency,N2 has the best pulp quality,insufficient or excessive N application was not conducive to the improvement of melon quality.At the same N level,the pulp quality of treatment F10 was higher than that of treatment F5 and F15.【Conclusions】Nitrogen level of 125 kg/hm^2 and the nitrogen application frequency of 10 day are recommended as the better combination,although its yield is slightly lower than that in nitrogen level of 160 kg/hm^2 and the application frequency of 5 day.