减氮结合宽窄行种植对小麦光合特性及产量的影响

Effects of Nitrogen Reduction Combined with Wide-Narrow Row Planting on Photosynthetic Characteristics and Yield of Wheat

试验于2018—2019、2019—2020年度连续两个小麦生长季,以商麦167为材料,设置N_(0)(不施氮肥)、N_(165)(减氮45%)、N_(210)(减氮30%)、N_(255)(减氮15%)和N_(300)(常规施氮)5个施氮水平,研究宽窄行种植条件下减施氮肥对小麦光合特性及产量的影响。结果表明,两年度小麦叶面积指数(LAI)均在开花期达最大值,且随施氮量降低花前呈降低趋势,花后呈先升后降趋势。叶片SPAD值均在N_(300)处理下达到最大值。随着施氮量降低,小麦叶片净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)均在开花期达最大值,且趋势均为先增后降,减氮15%处理下值最大,显著高于常规施氮处理;胞间CO_(2)浓度(Ci)变化趋势为先减后增,与Pn、Gs、Tr相反。随施氮量减少,单位面积穗数和穗粒数呈下降趋势,千粒重呈上升趋势,产量呈先增后减趋势,N_(255)处理产量最高,且除N_(300)外差异均达到极显著水平(P<0.01)。因此,小麦宽窄行种植模式下,在常规施氮量基础上减氮15%处理最有利于商麦167实现高产。

In this study,Shangmai 167 was used as the experimental material in two consecutive growing seasons of 2018-2019 and 2019-2020,and five nitrogen application levels were set as N_(0)(no nitrogen application),N_(165)(nitrogen reduction of 45%),N_(210)(nitrogen reduction of 30%),N_(225)(nitrogen reduction of 15%)and N_(300)(conventional nitrogen application).The effects of nitrogen reduction on photosynthetic characteristics and yield of wheat were studied under wide-narrow row planting.The results showed that leaf area index(LAI)of wheat reached the maximum value at flowering stage in both years,and decreased before flowering and increased first and then decreased after flowering with the decrease of nitrogen application rate.SPAD value reached the maximum under N_(300) treatment.With the decrease of nitrogen application rate,the net photosynthetic rate(Pn),stomatal conductance(Gs)and transpiration rate(Tr)of wheat leaves reached the maximum value at flowering stage,and their change trends were all as first increasing and then decreasing;the values reached the maximum under 15%of nitrogen reduction treatment,which were significantly higher than those of conventional nitrogen application treatment.The change trend of intercellular CO_(2) concentration(Ci)was first decreasing and then increasing,which was opposite to that of Pn,Gs and Tr.With the decrease of nitrogen application rate,the number of ears per unit area and grains per ear showed downward trends,the thousand-grain weight showed an upward trend,and the yield showed a trend of first increasing and then decreasing.The yield was the highest under N_(255) treatment,and the differences among treatments reached extremely significant level(P﹤0.01)except for N_(300) treatment.Therefore,under the wide-narrow row planting mode,15%of nitrogen reduction on the basis of conventional nitrogen application rate was the most beneficial to high yield of Shangmai 167.