基肥配施和拔节期追氮对鲜食糯玉米子粒热力学特性的影响

Effects of Basic Fertilizer Ratio and Nitrogen Topdressing at Jointing Stage on Thermal Properties of Fresh Waxy Maize Grain

以苏玉糯5号和渝糯7号为材料,研究基肥配施和拔节期追氮对鲜食糯玉米子粒热力学特性的影响。研究表明,热焓值和胶凝温度受基肥配施影响较小,回生热焓值和回生值受拔节期追氮影响较小。热力学特征参数中,以回生热焓值和回生值变异系数较高。基肥配施处理中,氮磷钾肥均衡配施时各参数较高。随着拔节期追氮量增加,胶凝温度(起始温度、峰值温度和终值温度)先升后降;热焓值、回生值在不追氮或追氮150 kg/hm2时无显著差异,在过量追氮(300 kg/hm2)时前者较低,后者较高。相关分析表明,胶凝温度3个指标两两极显著正相关,且回生值和回生热焓值极显著正相关。6个热力学特征参数可转换为3个独立的主成分,累计方差贡献率为97.2%。氮磷钾均衡基施并拔节期适量追氮时子粒热稳定性较好,回生值适中。

The results of a field experiment using Suyunuo5 and Yunuo7 indicated that fertilizer treatments sig- nificantly changed the thermal properties, and the effects of basic fertilizer on thermal characteristics were lower than those of nitrogen topdressing at jointing stage except for retrogradation enthalpy（△Hgel） and retrogradation per- centage（R）. The variation coefficient of AH, o, and R was higher than other thermal characteristics. Among basic fertil- izer treatments, all the thermal characteristics were highest when the fertilizer was balanced applied. With the incre- ment of nitrogen top-dressing at jointing stage, the gelatinization temperatures raise first and fall later. Gelatiniza- tion enthalpy（△Hgel） and R was similar between no topdressing treatment and topdressing 150 kg/ha N treatment, but the former was lower and the later was higher under topdressing 300 kg/ha N treatments. The thermal characteristics were different between years. The thermal parameters were higher in Suyunuo5 except for △Hgel, which was similar between two varieties. The onset, peak and conclusion temperatures were positively correlated each other at p〈0.01 level. The AH~, was significantly positive correlated to R. The six thermal parameters could transferred to three inde- pendent principle components and its cumulative contribution reached to 97.2%, indicated that peak temperature. The treatment of fertilizer was balanced applied as basic fertilizer had higher thermal stability and moderate R.