土壤类型和施氮量对连作春玉米产量及氮素平衡的影响

以吉林省春玉米连作体系为研究对象,采用多因素方差分析的方法,对多年田间定位试验结果进行分析比较,以探讨土壤类型变异对土壤―作物系统氮素平衡的影响。通过在相同气候条件下,2种土壤类型(黑土(黏化湿润均腐土)和风砂土(湿润冲积新成土))上开展的连续4年的氮肥施用量(0、168、312 kg hm~(-2))田间定位试验,研究了不同土壤类型间玉米产量、氮素矿化、残留及氮素表观损失的差异。结果表明,土壤类型显著影响玉米产量,黑土的玉米籽粒产量较高(6 469~10 106 kg hm~(-2)),平均为8 623 kg hm~(-2),风砂土的玉米籽粒产量较低(1 386~8 196kg hm~(-2)),平均为5911 kg hm~(-2);黑土和风砂土玉米籽粒产量的年际间(2009―2012年)变异系数分别为13.4%和59.1%,黑土的玉米籽粒产量稳定性显著大于风砂土;黑土连续4季氮素总表观矿化量为328 kg hm~(-2),为风砂土的2.2倍;受土壤质地影响,黑土收获后0~100 cm土层土壤矿质氮残留量为99~321 kg hm~(-2),显著高于风砂土(38~77 kg hm~(-2));在中等施氮(168 kg hm~(-2))条件下,黑土与风砂土的氮肥表观损失量无显著差异,分别为320 kg hm~(-2)和315 kg hm~(-2);当施氮量增加至312 kg hm~(-2)时,黑土和风砂土的氮肥表观损失量均显著增加,且风砂土的氮肥表观损失量达到827 kg hm~(-2),显著高于黑土。由于受土壤质地和土壤供肥能力的影响,土壤类型会对玉米产量、氮素矿化和表观损失有一定的影响,因此,在氮肥优化管理中应考虑土壤类型的变异。

Effect of Soil Type and Nitrogen Application Rate on Yield of Monocropping Spring Maize and Nitrogen Balance in Crop Field

Objective] Jilin Province is a major maize producing area and a key commodity grain production base of China.In the province,monocroppingof spring maize prevails in various types of soils.However,it is still not so clear how type of the soil affects yield of the crop,nitrogen mineralization and nitrogen residue in the soil and apparent loss of soil nitrogen from the maize monocropping system.Therefore,this study was performed to explore effects of the same nitrogen fertilization strategy in different types of soils under the maize monocropping system in an attempt to provide a certain basis for optimization nitrogen management.Method] Based on a long-term fertilization experimenton the spring maize monocropping in Jilin Province,multi-factor variance analysis was done of the data of the recent four years of the longterm experiment to determine effect of the soil,in terms of soil type,on N balance in the soil-crop system in Northeast China.During the four years,maize was monocropped in black soil (Argi-Udic Isohumosols) and sandy soil (Udi-Alluvic Primosols) and applied with three rates of N (0 kg hm-2,168 kg hm-2 and 312 kg hm-2,separately) under the same climate condition.Maize yields were monitored and soil samples analyzed for N mineralization rate,N residue and apparent N loss.Result] Maize grain yield varied with type of the soil and in the range of 6 469 ～ 10 106 kg hm-2 (8 623 kg hm-2 on average) in black soil and in the range of 1 386～ 8 196 kg hm-2 (5 911 kg hm-2) in sandy soil.Furthermore,grain yield stability also differed sharply between the soils.In the four years (2009-2012),variation coefficient of the yield in black soil was 13.4％ and in sandy soil 59.1％.Obviously the crop in black soil was more stable in yield than that in sandy soil.Total N mineralization rate was 328 kg hm-2 in black soil,2.2 times that in sandy soil.As affected by soil texture,the total residue of mineralized N residue in the 0～ 100 cm soil layer after harvest of the crop was in the range of 99 ～ 321 kg hm-2 in black soil,much higher than that (38 kg hm-2 ～ 77 kg hm-2) in sandy soil.Apparent N loss did not varied much between black soil and sandy soil applied with N at a medium rate (168 kg hm-2) and was 320 kg hm-2 and 315 kg hm-2,respectively.However,apparent N loss increased significantly or by 111.9％ and 162.5％,or by 358 kg hm-2 and 512 kg hm-2,respectively in black soil and sandy soil.The apparent N loss in sandy soil reached up to 827 kg hm-2,which was remarkably higher than that in black soil.Conclusion] Due to differences in soil texture and nutrient supplying capacity,soils of different types would differ significantly in maize grain yield,N mineralization rate,accumulated N residue and apparent N loss.Therefore,type of a soil should be taken into consideration in optimizing N fertilization management.