[Interactive effects of irrigation regime and planting density on grain yield and water use efficiency in winter wheat]. / 灌水量与密度互作对冬小麦籽粒产量和水分利用效率的影响.

To get an optimal irrigation regime and planting density for simultaneous improvement of grain yield (GY) and water use efficiency (WUE) in winter wheat, we examined the responses of 'Tainong 18' (with bigger ears) and 'Shannong 22' (with medium-sized ears) under four irrigation regimes, including 0, 45, 60, and 75 mm. Those two cultivars were planted at four densities: Tainong 18 at 135×104, 270×104, 405×104, and 540×104 plants·hm-2 and Shannong 22 at 90×104, 180×104, 270×104, and 360×104 plants·hm-2. The interactive effects of irrigation regimes and plant densities on GY, water consumption characteristics, and WUE were investigated. The results showed that GY, evapotranspiration, soil water consumption, and WUE were significantly affected by irrigation regime, plant density, and their interaction. The optimal irrigation regime was 45 mm for both cultivars, while the optimal plant density was 405×104 plants·hm-2 for Tainong 18 and 270×104 plants·hm-2 for Shannong 22, as indicated by the highest GY, the lowest ratio of soil evaporation to evapotranspiration after jointing, and higher WUE and the ratio of soil water consumption below 1 m to total soil water consumption. The rational combination of plant density and irrigation could reduce unnecessary water consumption and improve WUE.

[Correlation between nitrogen fruiting efficiency and nitrogen utilization and remobilization in winter wheat at different sowing dates]. / ä¸åŒæ’­æœŸå†¬å°éº¦æ°®ç´ å‡ºç±½æ•ˆçŽ‡ä¸Žæ°®ç´ åˆ©ç”¨åŠè½¬è¿çš„ç›¸å ³æ€§.

To understand the correlation between nitrogen fruiting efficiency and nitrogen utilization and remobilization in winter wheat, the differences and mutual relationships of nitrogen fruiting efficiency, nitrogen utilization and remobilization of winter wheat at different sowing dates (S1:24 September, S2:1 October, S3:8 October, S4:15 October and S5:22 October) were analyzed in two growing seasons from 2014 to 2016. The results showed that there was no significant difference in grain yield and grain number per unit area among different sowing dates. Delayed sowing date decreased nitrogen accumulation in both shoots and spikes, and then reduced nitrogen uptake efficiency and increased nitrogen utilization efficiency and nitrogen fruiting efficiency. Nitrogen fruiting efficiency was positively correlated with nitrogen utilization efficiency, negatively correlated with nitrogen uptake efficiency, but not significantly correlated with nitrogen use efficiency. Nitrogen nutrition index tended to be optimum with delayed sowing dates, showed synchronicity with the improvement of nitrogen fruiting efficiency. Pre-anthesis nitrogen remobilization amount in vegetative organs and post-anthesis nitrogen accumulation amount significantly decreased with postpone of sowing dates, but pre-anthesis nitrogen remobilization efficiency remarkably rise. There was a positive correlation between nitrogen fruiting efficiency and nitrogen remobilization efficiency, indicating that the improvement in nitrogen remobilization efficiency facilitated the increment in nitrogen frui-ting efficiency. Taken together, properly delayed sowing date reduced nitrogen uptake, but increased nitrogen utilization efficiency and nitrogen fruiting efficiency and improved nitrogen supply status, which provided a theoretical basis for the implementation of reducing input and improving nitrogen utilization efficiency in wheat production in this region.

[Effects of wide-range planting on the yield and nitrogen use efficiency of winter wheat cultivar Tainong 18.] / å®½å¹ æ’­ç§å¯¹å†¬å°éº¦'泰农18'äº§é‡å’Œæ°®ç´ åˆ©ç”¨çŽ‡çš„å½±å“.

The effects of wide-range planting (WR) versus drilling-planting (DP) on grain yield, nitrogen use efficiency (NUE), and nitrogen uptake efficiency (UPE) were investigated using winter wheat cultivar Tainong 18 at experimental fields in Tai'an and Yanzhou during the growing seasons of 2015 and 2016. The results showed that planting pattern, experimental field location, and their interaction significantly affected the grain yield, NUE, and related indices of cultivar Tainong 18. Compared to DP, the WR pattern significantly increased grain yield by 22.5% and 15.4% at Tai'an and Yanzhou, respectively, by raising the number of spikes per unit area at maturity (originating from the greater numbers of tillers per plant and per unit area) and the number of spikes per plant. Compared to DP, the WR pattern significantly increased UPE by 27.7% and 17.5% at Tai'an and Yanzhou, respectively. NUE with the WR pattern at Tai'an and Yanzhou was also increased, respectively, by 22.5% and 15.4% by enhancing nitrogen accumulation and increasing the UPE. A stonger positive effect on yield was observed at Tai'an than at Yanzhou. Thus, the popularization and application of a WR pattern would synergistically improve grain yields and NUE in winter wheat.