辽西风沙半干旱区氮肥减施对花生干物质积累和产量的影响

Effects of reduction of nitrogen application on dry matter accumulation and yield of peanut in semi-arid area of western Liaoning Province

为评估辽西风沙半干旱区花生减施氮肥的可行性及对花生产量的影响,以‘白沙1016’花生为研究材料,开展为期两年的试验(2018—2019年),设置不施氮(N0)、低氮(N1)、中氮(N2)和高氮(N3)4个处理,施氮量分别为0、40、80和120 kg·hm^(-2),研究雨养条件下施氮对单作花生产量和干物质积累的影响。结果表明:辽西降水时空变异大,2018和2019年分别为干旱年和丰水年。在两种年型下,增加施氮量均未显著提高花生产量和干物质。由于2018年前期水分条件限制,每平米荚数极显著低于2019年(P<0.01)。高氮水平下,单荚粒数减小,2018年显著高于2019年(P<0.01)。两年各施氮处理百粒重无显著差异。缺水的2018年氮肥效应发挥受限,影响叶片生长;2019年生长季水氮协调不佳,各处理下干物质无显著差异;但施氮缩短了花生达最大干物质量及最大生长率的时间;相较2018年,丰水的2019年施氮更有利于茎、叶干物质形成,但差异不显著。因此,在该干旱区可选择少施氮(40 kg·hm^(-2))的施肥方案,既不会因氮胁迫影响花生生长,还能减少农田和地下水污染,利于土地可持续发展。本研究可为风沙半干旱区氮肥减施、花生增产及保证粮食安全提供一定参考作用。

This study aimed to assess the effects of reducing nitrogen application on growth and yield formation of rainfed peanut in a semi-arid region of western Liaoning Province.The testing peanut variety was‘Baisha 1016’.A two-year experiment(2018-2019)was conducted with four nitrogen application levels,including no nitrogen(N0),low nitrogen(N1,40 kg·hm^(-2)),medium nitrogen(N2,80 kg·hm^(-2))and high nitrogen(N3,120 kg·hm^(-2)).There were substantial spatial-temporal variations of precipitation in western Liaoning,with 2018 being a dry year and 2019 being a wet year.Due to water limitation,increasing nitrogen application rate did not significantly affect peanut yield and aboveground dry matter in both years.Because of drought at early stage in 2018,the pod number per unit area was significantly lower than that in 2019(P<0.01).Under high nitrogen rate,seed number per pod decreased in 2018 but was higher than that in 2019(P<0.01).There was no significant difference in 100-seed weight between those two years.In 2018,nitrogen application effect was limited by water shortage,which directly impacted leaf growth.In 2019,water and nitrogen were not well coordinated in the growing season,thus resulting in no significant difference of dry matter among different treatments.However,high nitrogen rate shortened the time for peanut to reach maximum dry matter and maximum growth rate.Compared with 2018,high nitrogen rate increased stem and leaf dry matter formation in 2019,but without statistical significance.Therefore,low nitrogen application(40 kg·hm^(-2))could be applied in this semi-arid region.Such a scheme of nitrogen application would not affect the growth of peanut,and the pollution of cropland and groundwater would be largely reduced,which is conducive to sustainable land use.Our results provide a reference for reducing nitrogen application,increasing peanut yield,and ensuring food security in semi-arid regions.