| In view of the low water and nitrogen utilization efficiency in the oasis agricultural production areas in southern Xinjiang,this study passed field experiments at the characteristic forest and fruit test base of Xinjiang Agricultural University in Aksu,Xinjiang from 2017 to2018,taking winter wheat and reseeding maize as the research objects to explore different water and nitrogen utilization rates.The effects of gradients on growth indicators such as plant height,leaf area,dry matter and yield,as well as physiological indicators such as chlorophyll content,net photosynthetic rate,transpiration rate,and leaf water use efficiency of reseeding maize in winter wheat,using path analysis and response surface methodology to clarify crops The internal influence mechanism of physiological characteristics and yield and the response to water and nitrogen were analyzed.The growth and development of maize during the whole growth period of winter wheat replanting in southern Xinjiang was analyzed,and the optimal water and nitrogen application threshold suitable for the growth and development of replanting maize with winter wheat in southern Xinjiang was obtained.The water and nitrogen management measures for annual production of winter wheat and maize provide theoretical basis.The main research results are as follows:(1)Water and nitrogen have a significant effect on the plant height of winter wheat.The jointing to booting stage is the key growth stage.The irrigation amount of 282.9 mm and the nitrogen fertilizer amount of 207 kg/hm~2 are most conducive to the growth of winter wheat plant height and dry matter grain accumulation.High water and high fertilizer The highest yield of the treatment was 13.599 t/hm~2,followed by the medium water fertilizer treatment,which was 12.447 t/hm~2.However,the analysis found that the water use efficiency and harvest index of the medium water fertilizer treatment were better than those of the high water and high fertilizer treatment.In addition,the growth indicators and yield of winter wheat were There was a positive correlation,and the path analysis showed that the effective panicle number was a key factor in determining the yield of winter wheat.The comprehensive comparison showed that the water-nitrogen combination with the irrigation amount of 282.9 mm and the nitrogen fertilizer dosage of 207 kg/hm~2 was the optimal water-nitrogen combination for the growth and development of winter wheat,taking into account both yield and benefit.(2)The maximum plant height and leaf area index were obtained by re-seeding maize under medium water and fertilizer treatment.Increasing the amount of irrigation and nitrogen fertilizer significantly promoted plant height and leaf area,and high fertilizer treatment decreased the trend of growth index and continued to increase.The dry matter accumulation under the medium-fertilizer gradient showed a trend of first increasing and then decreasing with the increase of the irrigation amount.The maximum dry matter accumulation was 39.78 t/hm~2and the maximum yield was 12914.30 t/hm~2 with the medium-water fertilizer treatment.There was no significant difference between the index and the high water and high fertilizer treatments.Comprehensive analysis showed that the combination of 578.25～666.9 mm of irrigation and306.5 kg/hm~2 of nitrogen fertilizer was the most beneficial to achieve the growth index of reseeding maize and higher water and nitrogen use efficiency.Path analysis showed that the yield of reseeding maize and the 100-kernel weight of its constituent elements were the main factors determining the yield of maize.(3)The SPAD value of winter wheat showed a unimodal trend in the whole growth period,and the peak appeared in the heading and flowering stage and was most conducive to the accumulation of photosynthetic products.Increasing the amount of irrigation and nitrogen fertilizer application could significantly increase the net photosynthetic rate of winter wheat,at207 kg/hm~2～276 kg/hm~2 Nitrogen application range and increasing irrigation amount can delay leaf senescence,while the diurnal variation of Pn in winter wheat under no fertilization treatment showed a unimodal trend and the peak value was delayed.The transpiration rate of winter wheat under different water gradients showed a consistent law with the increase of nitrogen fertilizer application,and they all increased with the increase of nitrogen fertilizer application.Leaf water use efficiency showed a trend of increasing first,then decreasing,and then increasing sharply.Comprehensive comparison showed that the application range of 207-276 kg/hm~2 nitrogen fertilizer and the irrigation amount of 282.9 mm were the water and nitrogen application gradients suitable for the photosynthetic performance of winter wheat during the grain-filling stage.(4)Based on the response surface methodology to analyze the response of winter wheat and reseeding maize yields to water and nitrogen application,after optimizing the irrigation and nitrogen application thresholds,it was found that there is a partial interaction between winter wheat irrigation and fertilization,which promotes winter wheat yield,the effect of nitrogen application on wheat yield was more significant,but its upper threshold did not appear.The water-nitrogen interaction of reseeding maize showed an ellipse shape,and the effect of nitrogen fertilizer amount on the yield of reseeding maize was more significant.After the optimal prediction of the response surface,it was found that when the irrigation rate was 107.53%ET_C(621.79 mm)and the nitrogen fertilizer application rate was 381.917 kg/hm~2,the replanted maize in southern Xinjiang could play a synergistic effect under the interaction of water and nitrogen to obtain the best yield of 13027.3 kg/hm~2. |
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