1.State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences;2.Amway (China) Botanical R&D Centre, Wuxi;3.Institute of Vegetable Science, Jiangsu Academy of Agricultural Sciences
Supported by the Agricultural Science and Technology Innovation Fund of Jiangsu Province, China (No. CX(18)1005) and the Enterprise Cooperation Projects (No. Am20210407RD)
设施菜地揭棚休闲期种植填闲作物是阻控淋溶发生的重要措施，在降雨频繁地区氮磷阻控效率高的填闲作物尚不明确。以休闲为对照，种植5种填闲作物：高粱（Sorghum bicolor L.）、玉米（Zea mays L.）、黑麦草（Lolium perenne L.）、马齿苋（Portulaca oleracea L.）和羽衣甘蓝（Brassica oleracea var. acephala DC.），研究了不同种类填闲作物对设施菜地氮磷淋溶、土壤速效氮、土壤微生物的影响。结果表明：与休闲处理相比，种植填闲作物高粱、玉米、黑麦草、马齿苋和羽衣甘蓝分别显著减少了12.6、16.6、27.4、28.9和26.8 kg?hm-2的氮淋溶，显著减少了0.10、0.05、0.04、0.04和0.13 kg?hm-2的磷淋溶。氮淋溶阻控率由高到低依次为马齿苋、黑麦草、羽衣甘蓝、玉米、高粱，磷淋溶阻控率由高到低则依次为羽衣甘蓝、高粱、玉米、马齿苋、黑麦草。5种填闲作物中黑麦草、马齿苋和羽衣甘蓝的氮阻控率分别达到52.3%、55.1%和51.2%，较高粱和玉米氮阻控率平均提高了近一倍。这是因为黑麦草、马齿苋和羽衣甘蓝在休闲前期（21 d）就有一定的覆盖度，与休闲相比分别减少了23.5%、17.1%和26.7%的淋溶水量，而高粱和玉米前期覆盖度差，在前期降水多后期降水少的情况下其淋溶水量与休闲无显著差异；种植黑麦草、马齿苋和羽衣甘蓝耕层土壤（0~20 cm）中硝态氮的含量为40.1~52.8 mg?kg-1，而种植高粱和玉米土壤硝态氮的含量为67.8~72.7 mg?kg-1；此外，与高粱和玉米相比，马齿苋和羽衣甘蓝还显著提高了耕层土壤nirS型反硝化细菌和根际土壤中nosZ型反硝化细菌的丰度，可能增强了土壤的反硝化过程。综上，黑麦草、马齿苋和羽衣甘蓝作为降雨频繁地区的夏季填闲作物可显著减少氮磷淋溶，其中羽衣甘蓝对氮磷综合阻控的效果最佳。
【Objective】Planting catch crops in a protected vegetable field during the fallow season is an important practice to reduce the leaching loss of important nutrients. However, few studies have been done on catch crops with high nitrogen and phosphorus leaching control efficiency in frequent rainfall areas.【Method】This research set up five planting catch crop treatments (sorghum treatment, maize treatment, ryegrass treatment, purslane treatment and collard treatment) and a fallow treatment to study the effect of different kinds of catch crops on nitrogen and phosphorus leaching, NO3--N and NH4+-N content and soil microorganism.【Result】The results showed that compared with fallow treatment, sorghum, maize, ryegrass, purslane and collard treatments significantly reduced nitrogen leaching by 12.6, 26.6, 27.4, 28.9 and 26.8 kg?hm-2 and phosphorus by 0.10, 0.05, 0.04, 0.04 and 0.13 kg?hm-2, respectively. The nitrogen and phosphorus control efficiency was as follows: purslane＞ryegrass＞collard＞maize＞sorghum, and collard＞sorghum＞maize＞purslane＞ryegrass, respectively. The nitrogen control rates of ryegrass, purslane and collard reached 52.3%, 55.1% and 51.2%, respectively, which were nearly twice higher than the nitrogen control rates of sorghum and maize. This may be because the ryegrass, purslane and collard treatments had a certain coverage in the early fallow period (21 days), which reduced the leaching volume by 23.5%, 17.1% and 26.7% compared with fallow treatment. In contrast, sorghum and maize treatments had poor coverage in the early fallow period, hence there was no significant difference in leaching volume between sorghum and maize treatments and fallow treatment. In addition, the NO3--N content in the surface soil (0-20 cm) of ryegrass, purslane and collard treatments was 40.1-52.8 mg?kg-1, while in the surface soil of sorghum and maize treatments it was 67.8-72.7 mg?kg-1. Besides, compared with sorghum and maize treatments, ryegrass, purslane and collard treatments also significantly increased the abundance of nirS type denitrifying bacteria in surface soil and nosZ type denitrifying bacteria in rhizosphere soil, which may enhance the denitrification process in soil. This may be one of the mechanisms for high nitrogen leaching control efficiency.【Conclusion】In general, ryegrass, purslane and collard as the catch crops of protected vegetable field in areas with frequent rainfall can significantly reduce nitrogen and phosphorus leaching, and collard has the best effect on nitrogen and phosphorus comprehensive control.
JU Shengrong, MIN Ju, DONG Gangqiang, LI Jianbin, SHI Weiming. Effects and Mechanisms of Different Kinds of Catch Crops on Reducing Nitrogen and Phosphorus Leaching Loss in Protected Vegetable Field[J]. Acta Pedologica Sinica, DOI:10.11766/trxb202112010590,[In Press]