不同氮素及硝化抑制剂对叶菜用甘薯光合特性、茎叶产量及硝酸盐含量的影响

Studies on the effects of different fertilizers and nitrification inhibitor on photosynthetic and vine yield and nitrate accumulation in vine-vegetable sweetpotato

研究了铵态氮肥（NH4）2SO4、硝态氮肥NaNO3及硝化抑制剂双氰铵（DCD）对叶菜用甘薯光合特性、茎叶产量以及硝酸盐含量的影响。结果表明，不同氮肥类型和施氮量对叶菜用甘薯植株叶绿素含量及光合特性均有显著影响，其中硝态氮肥对叶绿素a含量、光合速率的影响大干铵态氮肥。施肥量对叶绿素a含量的影响达显著水平。单独施用铵态氮茎尖产量较其他氮肥类型低。纯氮用量在450kg／hm^2范围内。增加施氮量可提高茎叶产量，但超过此范围继续增加施氮量则增产效应不明显。硝态氮比铵态氮更容易提高硝酸盐含量；施氮量极显著影响硝酸盐含量，在低中施用量（150～450kg／hm^2）条件下，硝酸盐含量的峰值大约出现在8～9d，而高施用量（600～750kg／hm^2）条件下，硝酸盐含量的峰值在7～8d；DCD可以使施用铵态氮的叶菜用甘薯硝酸盐含量显著下降，但对施用硝态氮的叶菜用甘薯影响不显著。综合考虑产量与硝酸盐含量两因素，叶菜用甘薯最佳施肥采摘方案为，施纯氮450kg／hm^2，采用铵态氮结合DCD的方式施用，在施肥后第9天或第10天进行采摘。

This paper studied the photosynthetic,edible-vine yields and nitrate accumulation of vinevegetable sweetpotato character by using the （NH4）2SO4,NaNO3 and Nitrification inhibitor DCD. The results showed that there was a significant effect of applied nitrogen amount and nitrogen type on photosynthetic character and chlorophyll content. NO3-N had higher effects than NH3-N on the chlorophyll a and photosynthetic rate,and fertility application amounts evidently affected the content of chlorophyll a. Vine and leaf yield of single application of NH4^＋-N was lower than that of nitrogen treatment. Within the range of 450 kg pure nitrogen per hectare,with the increase of applied nitrogen,the yields of vine and leaf improved. But if the amount applied went out of that range ,increasing application of nitrogen couldn＇t notability affect the yield. The NO3-N application could increase the content of nitrate more easily. The highest nitrate level appeared 8-9 d after treating at medium and lower nitrogen level （150-450 kg/hm^2） and 7-8 d at higher nitrogen （600-750 kg/hm^2）. The DCD could reduce the NH3-N-genetic-nitrate content significantly but not significant for NO3-N. The best means was the combination of NH4-N and DCD,450 kg per hectare pure nitrogen and harvest after 9-10 d treatment.