优化氮肥用量和基追比例提高红壤性水稻土肥力和双季稻氮素的农学效应

发布时间：2018-12-17 13:22

【摘要】：【目的】优化氮肥用量和基追比例是实现氮肥减施和提高肥料利用率的重要途径。本研究在南方典型双季稻种植区进行定位试验,通过对土壤肥力与氮素农学效益进行综合评价,以期提出适合当地土壤和水稻种植条件的氮肥减施模式。【方法】以南方典型红壤区双季稻种植体系为研究对象,于2014~2015连续进行了4季大田定位试验,设处理:1)不施氮肥(T1);2)当地农民习惯施氮(T2),早稻、晚稻各施N 165和195 kg/hm~2,基肥∶蘖肥∶穗肥比分别为60∶40∶0、40∶30∶30;3)在T2处理基础上减施氮肥20%(T3),即早稻施N 135 kg/hm~2,晚稻施N 165 kg/hm~2,基肥∶蘖肥∶穗肥比均为40∶30∶30,并以20%有机氮代替普通化肥氮。分析了成熟期水稻产量和植物样氮素含量,测定了0—20 cm土壤微生物量碳、氮含量,土壤p H、有机质、全氮、速效钾和有效磷等理化指标,计算了累计氮肥利用率和氮肥农学效率,分别利用内梅罗指数法和灰色关联度法综合评价了土壤肥力效应以及各施肥模式的综合效益。【结果】1)各处理土壤综合肥力指数(IFI)值由高到低为T3T2T1;与T2处理相比,优化氮肥用量和基追比例的T3处理IFI值提高2.34%,土壤微生物量碳含量提高了4.37%~25.39%,土壤微生物量氮含量提高了17.85%~29.24%(P0.05)。2)与T2处理相比,2014 2015年T3处理累计氮肥农学效率显著提高了29.66%(P0.05),累计氮肥表观利用率显著提高了28.82%(P0.05);2014年各处理水稻总产量无显著差异,2015年水稻总产量T3处理比T2处理提高了5.26%,两年水稻总产量,T3处理提高了2.38%。3)对土壤养分指标、土壤微生物指标和氮素农学效率指标进行关联度分析,2014~2015年T3处理关联度最大,分别为0.9999和1.0000,在土壤肥力和氮肥农学效应综合评价中最优,表明优化氮肥用量和基追比例能够实现氮肥减施以及肥料利用率的提高。【结论】在当地农民习惯施氮的基础上减施20%化肥氮,以有机氮替代,并适当提高化肥氮在抽穗期的比例,能够保证土壤综合肥力的可持续性、氮素养分持续高效利用和水稻持续稳产。
[Abstract]:[objective] to optimize the amount of nitrogen fertilizer and the ratio of base to topdressing is an important way to reduce the application of nitrogen fertilizer and improve the fertilizer efficiency. In this study, the location experiment was carried out in the typical double cropping rice planting area in southern China, and the comprehensive evaluation of soil fertility and nitrogen agronomic benefit was carried out. With a view to proposing a nitrogen fertilizer reduction model suitable for local soil and rice planting conditions. [methods] A field location experiment of four consecutive seasons was carried out in 2014 / 2015, taking the cropping system of double cropping rice in the typical red soil region of southern China as the research object. Set up treatment: 1) do not apply nitrogen fertilizer (T1); 2) the local farmers used to apply nitrogen (T2), early rice and late rice with N 165 and 195 kg/hm~2, basal fertilizer, respectively. The ratio of tillering fertilizer to panicle fertilizer was 60: 40: 0: 40: 30: 30; 3) applying 20% nitrogen fertilizer (T3) on the basis of T2 treatment, that is, applying N 135 kg/hm~2, N 165 kg/hm~2, base fertilizer: tillering fertilizer to panicle fertilizer ratio of 40: 30: 30 in early rice, and replacing common fertilizer nitrogen with 20% organic nitrogen. The yield of rice and the nitrogen content of plant samples at maturity stage were analyzed. The soil microbial biomass carbon, nitrogen content, soil pH, organic matter, total nitrogen, available potassium and available phosphorus were determined for 0-20 cm, and the physical and chemical indexes such as soil microbial biomass carbon, nitrogen content, soil pH, total nitrogen, available potassium and available phosphorus were determined. The cumulative nitrogen use efficiency and the agronomic efficiency of nitrogen fertilizer were calculated. The effect of soil fertility and the comprehensive benefit of each fertilization model were evaluated by Nemero index method and grey correlation method respectively. [results] 1) the (IFI) value of comprehensive fertility index of each treatment was from high to low to T _ 3T _ 2T _ 1; Compared with T2 treatment, the IFI value of T3 treatment with optimized nitrogen application and the ratio of base to topdressing increased by 2.34, and the soil microbial biomass carbon content increased by 4.37 ~ 25.39. Soil microbial biomass nitrogen content increased by 17.85% (P0.05). Compared with T2 treatment, the cumulative nitrogen agronomic efficiency of T3 treatment increased by 29.66% (P0.05) in 2014 and 2015, respectively. The cumulative apparent nitrogen use efficiency increased by 28.82% (P0.05). There was no significant difference in total rice yield among different treatments in 2014. In 2015, total rice yield in T3 treatment was 5.26% higher than that in T2 treatment, and total rice yield in two years and T3 treatment increased 2.38.3) on soil nutrient index. The correlation degree of soil microbial index and nitrogen agronomic efficiency index was analyzed. The correlation degree of T3 treatment from 2014 to 2015 was the largest (0.9999 and 1.0000respectively), which was the best in the comprehensive evaluation of soil fertility and agronomic effect of nitrogen fertilizer. The results showed that optimizing the amount of nitrogen fertilizer and the ratio of base to topdressing could achieve the reduction of nitrogen application and the increase of fertilizer utilization efficiency. [conclusion] based on the local farmers' habit of applying nitrogen, 20% of fertilizer nitrogen could be reduced and organic nitrogen could be replaced. Increasing the proportion of fertilizer nitrogen at heading stage can ensure the sustainability of soil comprehensive fertility, the sustainable and efficient utilization of nitrogen nutrients and the sustainable and stable yield of rice.
【作者单位】：四川农业大学环境学院;中国农业科学院农业资源与农业区划研究所/耕地培育技术国家工程实验室;
【基金】：国家重点基础研究发展计划(973项目)课题(2013CB127406) 国家自然科学基金(21577172,41501322) 国家国际科技合作专项(2015DFA20790) 中央级公益性科研院所资金项目(IARRP-2015-21)资助
【分类号】：S511.42;S158

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