基于叶片SPAD值的滴灌春小麦氮肥分期施用推荐模型

试验于2014—2015年进行,利用2014年田间试验建立基于叶片SPAD值的滴灌春小麦氮肥分期施用推荐模型,2015年进行推荐模型的验证实验。结果表明:在滴灌春小麦拔节期、孕穗期、抽穗期和灌浆期,随着氮肥施用量的增加,小麦叶片SPAD值均呈线性增加的趋势;各生育期叶片SPAD值与产量具有显著的相关性;全生育期最佳施氮量为261 kg·hm-2;滴灌春小麦拔节期、孕穗期、抽穗期和灌浆期叶片SPAD临界值分别为42.4、39.4、41.8、54.1;建立了基于叶片SPAD值的滴灌春小麦氮肥分期施用推荐模型,在保证产量的前提下,基于模型推荐施肥可以节约肥料7.86%,提高氮肥利用率9.64%。研究得出,小麦叶片SPAD值可以指导滴灌春小麦氮肥分期施用。

Recommendation model of nitrogen fertilizer based on SPAD of leaves for drip-irrigated spring wheat

To explore a nitrogen fertilizer recommendation using SPAD-502 for drip-irrigated spring wheat,an ex-periment had been carried out between 2014 and 2015 .Field test data in 2014 was applied to establish a nitrogen fertiliz-er recommendation model based on SPAD of leaves for drip-irrigated spring wheat,which was compared with the field test in 2015 .The results showed that the SPAD of wheat leaves presented a liner increasing trend with the increase of N fer-tilizer rate at jointing,booting,heating and filling stages .The corresponding thresholds of SPAD were 42 .4,39 .4, 41 .8,and 54.1,respectively,when the total application rate of nitrogen fertilizer was 261 kg·hm-2 during the whole growth period of spring wheat .As a result,a nitrogen fertilizer recommendation model based on the SPAD of leaves could be established in this experiment .Field experiment indicated that the nitrogen fertilizer recommendation model could make the fertilizer application rate down by 7 .86%and the utilization ratio up by 9 .64%when wheat yield is secured .