施用控释肥对设施番茄NO_3^-—N淋洗、N_2O排放及产量与品质的影响

Effects of Controlled Release Fertilizer on Soil Nitrate Leaching, N_2O Emission and Fruit Yield and Quality in Greenhouse Tomato Production System

以京郊番茄为对象,研究了聚合物包膜控释肥不同用量与有机肥配合施用对设施生产体系产量和品质、硝态氮淋洗和N2O排放的影响。试验设对照(CK)、有机肥(N 134kg·hm-2,OM)、控释肥低量(控释N300kg·hm-2+有机肥N134kg·hm-2,N1)、控释肥中量(控释N 450 kg·hm-2+有机肥N 134kg·hm-2,N2)、控释肥高量(控释N600kg·hm-2+有机肥N134kg·hm-2,N3)、习惯施肥(速效N600 kg·hm-2+有机肥N 134 kg·hm-2,N4)共6个处理,用土壤溶液提取器测定淋洗液硝态氮浓度,静态箱法测定N2O排放。结果表明,与习惯处理(N4)相比,3个控释肥处理(N1、N2、N3)氮素淋洗损失明显减少,60 cm和100 cm土层的提取液硝态氮平均浓度降幅分别为15.4%~24.0%和17.8%~30.0%,拉秧后0~100cm土壤剖面硝态氮残留降低21.0%~59.8%。各处理N2O平均排放通量为60~144μg N·m-2·h-1,实际排放量为2.47~5.33kg·hm-2,施肥造成的N2O排放损失率为0.08%~0.39%;与习惯处理相比,控释肥处理平均减排38.1%~47.0%。番茄产量介于113~132 t·hm-2,N2处理产量最高,但处理间未见显著差异;N4处理的番茄硝酸盐含量最高,与对照差异显著。与习惯处理的多次施肥相比,控释肥与有机肥混配一次性基施显著降低了硝态氮淋洗量和N2O排放损失,控释肥高氮水平下氮素损失风险有增加趋势。试验结果显示施用中低量控释肥为协调番茄高产、高效与环保的较好选择。

Excessively high nitrogen fertilization and irrigation in intensive greenhouse vegetable production to maximize yield are very common practices in China. However, these has greatly increased the risk of N losses and caused serious non-point source pollution. Production systems with more yields and less environmental impacts are urgently needed. The objectives of this field study were to evaluate the effects of application of controlled-release fertilizers（CRF）and manure on fruit yield and quality, NO3^--N leaching and N2O emission from a highyield tomato production system in greenhouse in a Beijing suburb. Six treatments were used：no fertilizer N treatment（CK）, organic fertilizer（OM）, controlled-release fertilizer at nitrogen rate of 300 kg·hm^-2（N1）, controlled-release fertilizer at 450 kg·hm^-2（N2）, controlled-release fertilizer at 600 kg·hm^-2（N3）and traditional fertilization at 600 kg·hm^-2（N4）, and N1, N2, N3 and N4 treatments received the same amount of manure with that of OM treatment, respectively. The experimental design was a randomized complete block with three replications,and each plot was 13.2 m2（1.2 m×11 m）. All treatments were irrigated based on soil moisture sensor, starting at 60% available soil water（ASW）and ending at 90%ASW. Nine times of furrow irrigation were applied with 180 mm irrigation water in total. High-yield crop management practices were adopted. Soil leachate was collected with a soil solution extractor at 60 cm and 100 cm soil depth, and N2O emission was measured with the closed chamber technique. The average nitrate concentrations of soil leachate at depth of 60 cm and 100 cm from three controlled-release fertilizer treatments were reduced by 15.4%～24.0% and 17.8%～30.0%,respectively, and soil residual nitrate in 0～100 cm at harvest was reduced by 21.0%～59.8% compared with the traditional treatment, indicating that the nitrate leaching losses in the controlled-release fertilizer treatments were much lower than in the traditional treatment. Average N2O flux of all treatments were 60 μg N·m^-2·h^-1 to 144 μg N·m^-2·h^-1. The seasonal N2O emissions ranged from 2.47 kg·hm^-2to 5.33 kg·hm^-2, accounting for 0.08%～0.39% of applied fertilizers. Compared with the traditional treatment, controlled-release fertilizer treatments reduced N2O emission by 38.1%～47.0%.Fruit yields of all treatments were 113～132 t·hm^-2, with the highest in the N2 treatment. However, there were no significant differences between treatments. Nitrate concentration in fruits in the N4 treatment was significant higher than in the CK. In conclusion, single basal application of controlled-release fertilizers and manure together can significantly reduce nitrate leaching loss and N2O emission compared with the traditional fertilization. The use of controlled-release fertilizer should be at 300 kg·hm^-2 and 450 kg·hm^-2 as there is an increasing risk of N losses at higher rates of controlled-release fertilizer（ 600 kg·hm^-2）.