| In order to discuss the discipline of nutrient transport and yield formation of spring maize in Ningxia dryland.Use Xianyu 698 and two kinds of fertilizer type were normalN and controlled-release N as material to apply five nitrogen treatments with the random block design experiment,which studied the effects of nitrogen fertilizer on the growth and development,key enzyme activities,dry matter and nutrient accumulation characteristics,yield and yield components of spring maize.The results show:1.Reasonable nitrogen fertilizer can significantly increased maize growth.The total dry matter accumulation of T2,T3 and T4 in controlled-releaseN treatments compared with CK and T1 respectively increased by 18.82%,26.38%,20.02%and 9.92%,16.61%,10.76%and root vigor is also significantly higher.Meanwhile,reasonable nitrogen fertilizer can significantly improve the root length,root weight and root volume in the horizontal and vertical distribution of maize roots,that combined application 75 kg/hm2 normalN and 150 kg/hm2 controlled-releaseN is more beneficial to promote root growth,Which promoted the growth and development of whole maize.2.Reasonable nitrogen fertilizer can significantly increase the activity of antioxidant enzyme and key enzymes during N metabolism in maize.The NRA activity of T2,T3 and T4 compared with CK and T1 respectively increased by 45.06%,50.50%,45.72%and 7.28%,10.74%,7.48%;GSA activity increased by 66.34%,78.78%,73.21%and 27.22%,33.66%,29.70%.Meanwhile the antioxidant enzyme activities of maize also showed different degree of improvement,indicating that reasonable nitrogen fertilizer scheme could alleviate the effect of drought on spring maize to a certain extent.3.In the dry matter accumulation and distribution of maize,the vegetative period is mainly distributed in leaves and stalks;After the tasseling period,the dry matter distribution began to turn to the pan and grains.The dry matter in the leaf and stem gradually decreased the panicle transfer and eventually turned to the grain,and controlled-releeaseN was significantly higher than CK and T1.The contribution rate of dry matter to grain was as follows:leaf>stem.The contribution rates of T2,T3 and T4 treatments respectively were 19.92%,21.95%and 22.40%,which was beneficial to the promotion of dry matter transport to grain.4.Reasonable nitrogen fertilizer can significantly improve the accumulation,distribution and operation of nutrient accumulation in maize,and the distribution of nitrogen accumulation in T2,T3 and T4 treatment is higher than CK and T1 treatment.The nitrogen transfer rate(rate)and the contribution rate of controlled-releaseN were higher than other treatments,and also showed leaf>stem.To fertilizer utilization rate,combined application 75 kg/hm2 normalN and 150 kg/hm2 controlled-releaseN in the terms of the treatment of partial productivity(PEP),agronomic efficiency(AE),physiological utilization(PE)and recycling efficiency(RE)performed the best,respectively by 56.67%,35.91%,45.86%and 49.80%,and the harvest index(HI)was 29.94%.5.The order of maize yield was T3>T4>T2>T1>CK,and the treatment of T3 compared with CK and T1 was significantly increased by 36.97%and 12.57%.In the yield components,the controlled-releaseN treatments showed a higher degree performance than CK and T1 treatments.Among them,the most important constituent factors were 100 grain weight,and T2,T3,T4 treatment compared with CK and Tlrespectively increased by 12.78%,15.27%,10.90%and 9.17%,11.61%,7.41%,andalso use the most favorable ways of combined application 75 kg/hm2 normalN and 150 kg/hm2 controlled-releaseN to obtain high yield. |
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