摘要:吉林省黑土区是我国玉米生产的重要基地, 农业集约化程度较高, 农业面源污染风险较大。因此, 掌握吉林省黑土区降雨与农田氮磷淋溶的关系, 对区域生态农业可持续发展意义重大。本研究基于吉林省4个面源污染监测点, 于2016—2019年春玉米季对降雨情况、淋溶量、淋溶液氮磷浓度及淋溶强度等进行了动态监测, 系统分析了吉林省黑土区自然降雨与农田氮磷淋溶的关系。结果表明: 1)吉林省黑土区降雨年际间和监测点间差异较大, 年际间波动在424~554 mm, 春玉米全生育期平均降雨量为475 mm; 不同监测点降雨量大小依次为通化(593~785 mm)>公主岭(512~699 mm)>梨树(305~434 mm)>农安(197~342 mm)。2)淋溶量和降雨强度呈极显著正相关关系, 降雨强度每增加10 mm·(24h)-1, 淋溶量增加1.81 mm。全生育期(4—10月)降雨量与淋溶次数、淋溶概率分别呈极显著和显著正相关, 降雨量每增加100 mm, 淋溶次数约增加3次, 淋溶概率上升6%。当全生育期降雨量超过74 mm时, 淋溶概率增加, 可能引起淋溶; 而当全生育期降雨量达到217 mm时, 淋溶次数增加, 可以发生淋溶。产生淋溶的降雨等级一般以中雨(10~24.9 mm)和大雨(25~49.9 mm)为主。3)淋溶量和淋溶液总氮浓度呈极显著正相关, 与总磷浓度无明显相关关系。4)总氮淋溶强度与降雨强度呈极显著正相关, 降雨强度每增加10 mm·(24h)-1, 总氮淋溶强度增加0.73 kg·hm-2, 而总磷淋溶强度与降雨强度无明显相关性。由此可见, 吉林省黑土区农田在春玉米雨养条件下以氮素淋溶为主, 且与降雨密切相关, 应因地制宜采取农艺措施在源头上阻控农业面源污染的发生, 为农业生态可持续发展提供有效途径。
关键词:黑土区/
降雨/
氮磷淋溶/
春玉米
Abstract:The black soil area of Jilin Province is important for maize production in China, where agricultural development and nonpoint source pollution risks are intensifying. Understanding the effects of nitrogen and phosphorus leaching from rainfed spring maize farmland is important for the sustainable development of the region. This study investigated rainfall and leaching amounts, nitrogen and phosphorus leachate concentrations, and leaching intensity from 2016 to 2019 at four nonpoint source pollution monitoring stations in Jilin Province, China, and analyzed the relationship between rainfall and farmland nitrogen and phosphorus leaching. The results showed that the inter-annual and inter-regional rainfall differences were large, ranging from 424 to 554 mm. The average rainfall during spring maize growth season was 475 mm. Tonghua monitoring station had the most rain (593–785 mm), followed by Gongzhuling station (512–699 mm) and Lishu station (305–434 mm); Nong'an station had the least rain (197–342 mm). Tonghua and Nong'an growth seasons had primarily light and moderate rain, and Gongzhuling and Lishu had moderate and heavy rain and thunderstorms. There was a significant positive correlation between the leaching amount and rain intensity (P < 0.01). For every 10 mm·(24h)-1 increase in rain intensity, the leaching amount increased by 1.81 mm. Rainfall during the spring maize growth season (April to October) was also significantly correlated with the leaching amount (P < 0.05). For every 100 mm rain increase, the leached sample number and the leaching probability increased (3 times and 6%, respectively). When the growing season rainfall exceeded 74 mm, the leaching probability increased, and when it exceeded 217 mm, leaching could occur. Leaching occurred when rain levels were 10.0–24.9 mm (moderate rain) and 25.0–49.9 mm (heavy rain). There was a significant positive correlation between leaching amount and total nitrogen concentration, but no correlation with total phosphorus concentration. The total nitrogen leaching intensity had a strong positive correlation (P < 0.01) with rain intensity; for every 10 mm·(24h)-1 increase in rain intensity, the total nitrogen leaching intensity increased by 0.73 kg·hm-2. The total phosphorus leaching intensity did not correlate with rain intensity. Nitrogen primarily leached from black soil area farmland in Jilin Province during the rainfed spring maize growth season and was correlated with rainfall. Agronomic measures should be adopted to prevent agricultural nonpoint source pollution at the source.
Key words:Black soil area/
Rainfall/
Nitrogen and phosphorus leaching/
Spring maize
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