高基施比例条件下施氮量对覆膜种植烤烟氮素利用的影响

2009年采用大田小区试验,在广东南雄烟区探讨了高基肥比例条件下(无机肥料N基追比为7:3)施N量对覆膜种植烤烟N素利用的影响。试验结果表明:①饼肥和猪粪(N=64.50 kg/hm2,其中饼肥N 42.00%,不施用无机肥料N)有较强的持续供N能力,在烤烟移栽后30~75天使烟株根际土壤NO3--N浓度仍能维持在550.00 mg/kg以上;②在基施饼肥和猪粪(N=64.50 kg/hm2)的基础上,增施48~168 kg/hm2的无机N肥可显著提高烤烟移栽后75天前烟株根际土壤NO3--N含量,但在移栽75天后烟株根际土壤NO3--N积累效应不显著;③试验无机肥料供N范围内(48~168 kg/hm2),施N量对烤烟产量、产值、等级结构和内在化学品质无显著影响,但48 kg/hm2的施N量处理其N肥利用率和农学利用率极显著高于108kg/hm2和168 kg/hm2处理;④在广东南雄烟区地膜覆盖栽培条件下,基施64.50 kg/hm2有机N、配施48 kg/hm2无机N(基追比为7:3)可有效满足烤烟N素营养需求,提高N肥利用率和烟农的经济效应。

Effects of different nitrogen levels on n absorption and utilization of flue-cured tobacco use film mulching under high base fertilizer

To study the effects of different nitrogen levels on N absorption and utilization of flue-cured tobacco under high base inorganic N(70% applied as basal),a field experiment was conducted at Nanxiong in 2009.The results showed that:(1) Combination of cake fertilizer and pig manure(N = 64.5 kg/hm2;nitrogen of cake fertilizer,42%) exhibited the strong ability of nitrogen supplying in tobacco growth period.From it,nitrate content in tobacco rhizosphere was 550 mg/kg above during 30 to 75 days after transplanting.(2) Use film mulching in the root extending stage and supplying with the same organic fertilizers,soil nitrate content at the early stage was promoted evidently under the treatment of low inorganic N(48 kg/hm2) when some of NO3——N(15.98 kg/hm2)applied as base,and nitrate content of rhizosphere amount to 1 300 mg/kg above during 30 to 50 days after transplanting,meanwhile nitrogen uptake by tobacco was not affected significantly from it.(3) Based on the same organic fertilizers,nitrate of rhizosphere was enhanced significantly by the increase of inorganic N before 75 days after tobacco transplanting.However,because the increase of nitrate loss from rhizosphere after removing film in the root extending stage,there was no significant influence on nitrate accumulation in rhizosphere from inorganic N after 75 days of transplanting.(4) In this study,both tobacco nitrogen use efficiency and nitrogen agronomic efficiency decreased drastically followed with the increase of inorganic N from 48 kg/hm2 to 168 kg/hm2.Under film mulching in the root extending stage,suitably reducing inorganic N combined with high base inorganic N(70% applied as basal) could enhance the effect of N application significantly.