| This study set up three different patterns,including with rainfed(RI),traditional irrigation(TI),and micro-sprinkling irrigation(MI)under a field trial,with ’Yannong 19’ as the experimental variety,to investigate the effects of different irrigation and fertilizer application patterns,as well as compaction after sowing,on wheat yield and water and nitrogen utilization in the Huaibei area.N-fertilizer was all applied as basal fertilizer under rain-fed,and 60% basal application + 40% at jointing for traditional irrigation,and 60%basal application + 20% at jointing + 20% at booting for micro-sprinkling irrigation.Compaction after wheat sowing treatments(RC,TC and MC)were set under each pattern,six treatments in total.Investigations were conducted on wheat’s agronomic characteristics,flag leaf physiological traits,root growth and senescence,dry matter accumulation,grain yield,and water and nitrogen utilization.The intrinsic mechanisms of various water and N-fertilizer management patterns and compaction after sowing affecting wheat yield,water and nitrogen utilization in Huaibei area were clarified by examining the effects on seedling quality,late senescence of flag leaf,yield formation,and water and nitrogen utilization of wheat.The main research results are as follows:(1)Compared with RI and TI,MI treatment significantly increased the number of tillers,plant height,leaf age and number of primary roots,population dry matter accumulation increased by 43.75% and 16.85%,leaf area index and chlorophyll content increased by50.37%、10.32%,33.54% and 7.25%,respectively.MI stabilized the activity of protective enzymes in leaves,and the content of malondialdehyde(MDA)in leaves decreased by39.63% and 26.99%,respectively.Compared with no compaction treatment,soil compaction after sowing significantly increased the number of tillers and secondary roots of seedlings under rain-fed pattern,increased the population dry matter accumulation by6.10%,increased the leaf area index and chlorophyll content by 8.14% and 7.63%,respectively,and significantly decreased the MDA content of leaves.Under traditional flood irrigation and micro-sprinkling irrigation,compaction and no compaction treatment had no significant effect on the growth of wheat seedlings during the overwintering period.(2)Compared with RI and TI,the grain yield of MI was significantly increased by40.00% and 16.25%,respectively.The highest grain yield of MI was due to the significant increase of spike number,grain number per spike and 1000-grain weight.Under the rainfed pattern,the yield of soil compaction after sowing was 6.17% higher than that under the no compaction treatment,there was no significant effect of soil compaction after sowing on yield under micro-sprinkling irrigation and traditional flood irrigation patterns.Compared with RI and TI,MI significantly increased pre-anthesis dry matter remobilization amount(DMRA)and contribution of dry matter production to grain yield(CDMP).In rainfed pattern,soil compaction after sowing significantly decreased DMRA and increased CDMP.The chlorophyll content and activities of protective enzymes in flag leaves of MI were significantly higher than those of TI and RI,and RI was significantly the lowest,while MDA content in flag leaves of RI was significantly higher than that of TI and MI,and MI was the lowest.Under rain-fed,soil compaction after sowing treatment significantly increased the chlorophyll content and catalase(CAT)activity of flag leaves from 0 to 14 days after flowering,and decreased the MDA content of flag leaves from 0 to 7 days after flowering.Compared with RI and TI,MI significantly increased the root length density(RLD)of wheat in 0-60 cm soil layer at jointing stage and maturity stage,and RLD of RI treatment was significantly lower than that of TI.MI significantly enhanced the activity of root protective enzymes and decreased the content of MDA at grain filling stage.Under rain-fed pattern,soil compaction after sowing significantly increased root length density,root activity and superoxide dismutase(SOD)activity in 0-20 cm soil layer,and decreased root MDA content,however,the root activity and protective enzymes activities were not significantly affected by the soil compaction after sowing under traditional flood irrigation and micro-sprinkling irrigation patterns.(3)Compared with RI and TI,water use efficiency(WUE)of MI was significantly increased,and WUE was increased by 5.04% and 17.92%.The WUE was significantly increased by soil compaction after sowing under rain-fed pattern compared with the no compaction treatment,while the WUE was not significantly affected by soil compaction after sowing under traditional flood irrigation and micro-sprinkling irrigation.The total nitrogen at maturity(TNM),nitrogen accumulation grain(NAA)and pre-anthesis N remobilization amount(NRA)of wheat were significantly higher in MI than in TI and RI,and the lowest in RI.Compared with RI and TI,the contribution of N absorption to grain yield(CAN)increased by 18.53% and 7.22% in MI treatment.In rain-fed pattern,the soil compaction after sowing treatment significantly increased TNM,NAA,and CAN compared with the no compaction treatment.The nitrogen partial factor productivity(NPFP)and nitrogen harvest index(NHI)under different water and fertilizer patterns showed that MI was significantly higher than RI and TI.Soil compaction after sowing significantly increased NPFP and NHI under rain-fed,while soil compaction after sowing had no significant effect on nitrogen use under traditional flood irrigation and micro-sprinkling irrigation.In conclusion,micro sprinkling water and fertilizer integrated irrigation mode can promote the formation of strong wheat seedling before winter,improve grain yield,water use efficiency and nitrogen harvest index in Huaibei area.The effect of soil compaction after sowing under traditional flood irrigation and micro-sprinkling irrigation pattern on wheat yield and water and nitrogen use was small,while the effect of soil compaction after sowing under rain-fed pattern was significant. |
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