作 者 ：王飞 林 诚 林新坚 何春梅 李清华 李 昱 黄功标 钟少杰
期 刊 ：植物营养与肥料学报 2014年 20卷 4期 页码：896-904
Keywords:Astragalussinicus, rice, nitrogenuseefficiency, 15Nisotope, nitrogenresidue,
摘 要 ：【目的】紫云英翻压后在一定程度上可改善土壤理化性状，并提高后作水稻的产量，但是该机理是由于紫云英翻压矿化后提供的氮素还是由于与翻压紫云英后化肥氮素利用率的提高有关尚不清楚，因此，本项目通过连续4年紫云英翻压还田的定位试验与原状土柱模拟及15N示踪，研究了福建单季稻区紫云英压青回田对水稻产量与化肥15N吸收、 分配及残留的影响。【方法】采用单季稻田间定位试验，设5个处理： 1）对照，不翻压紫云英，不施化肥（CK）；2）不翻压紫云英，常规化肥施用量（100%H）；3）紫云英＋常规化肥用量（Z+100%H）；4）紫云英＋60%的常规化肥（Z+60%H）；5）只翻压紫云英，不施化肥（Z）。常规化肥用量（100%H）为施氮量N 135 kg/hm2，N∶P2O5∶K2O=1∶0.4∶0.7，每年紫云英翻压量为18000 kg/hm2。每个处理3次重复，小区面积15 m2，种植水稻为每小区20×15丛。于定位试验的第4年，在田间定位试验小区中，采用15N-尿素（丰度10%）示踪法与原状土柱模拟水稻植株的氮素吸收及分配情况。PVC管直径25 cm，长35 cm，其中压入田面下20 cm，每小区埋两个土柱，每个土柱中种植两株水稻。【结果】紫云英年翻压18000 kg/hm2并结合施用100%化肥（Z+100%H），水稻子粒4年平均产量比单施100%化肥（100%H）增产6.5%，同时在18000 kg/hm2 的紫云英翻压量下，主作物水稻化肥减量40%（Z+60%H）的产量与100%H的处理基本相当。Z+100%H处理对提高水稻分蘖期植株氮含量最为明显，尤其是茎叶氮含量较100%H提高7.0%，差异显著。虽然不同施肥处理水稻生育期的化肥氮素利用率无明显变化，但Z+100%H处理分蘖期与成熟期植株氮素吸收量分别较100%H提高23.0%与18.0%，说明绿肥与化肥配施有利于水稻植株吸收外源氮素，且植株吸收氮的差异主要来自于紫云英矿化的氮源。Z+60%H 与100%H处理的分蘖期与成熟期植株氮素吸收量则基本相当。不同施肥处理均有提高土壤全氮含量的趋势；Z+60%H 处理的耕层土壤化肥氮素的残留率最高，并显著高于Z+100%H处理。【结论】连续4年翻压紫云英明显提高了福建单季稻区黄泥田的农田生产力，在减少40%常规化肥用量的情况下仍可维持产量稳定。翻压绿肥减肥增效的主要机制之一是紫云英矿化的养分替代了化肥。
Abstract:【Objectives】Overturning Astragalus sinicus into paddy fields can improve soil physical and chemical properties and raise the output of after crop rice to some extent. However, it is still unclear that whether it is from the extra N input after overturning Astragalus sinicus or the improvement of nitrogen use efficiency. Data were collected from a 4-years continuous field experiment of overturning Astragalus sinicus into paddy fields and supplementary undistributed soil column simulation by 15N isotopic tracer, effects of the overturning on rice yield and N absorption, distribution and residue of 15N isotope of chemical fertilizer were investigated in single-crop rice regions of Fujian province.【Methods】 Field experiment with five treatments was implemented： 1)control, no overturning Astragalus sinicus and no chemical fertilizer(CK); 2) only applying chemical fertilizer(100%H); 3) Astragalus sinicus combined with 100% of chemical fertilizer (Z+100%H); 4) Astragalus sinicus combined with 60% of chemical fertilizer (Z+60%H); 5) only overturning Astragalus sinicus(Z). The amount of chemical nitrogen fertilizer was N 135 kg/ha, N∶P2O5∶K2O=1∶0.4∶0.7，and the amount of annually overturning Astragalus sinicus was 18000 kg/ha. Each treatment was set up in 3 replicates. The plot area was 15 m2 and cultivated with 20×15 clumps plant. In the fourth year of the experiment, supplementary undistributed soil column simulation by 15N isotopic tracer(10% abundance) was investigated to reveal the N absorption, distribution of chemical fertilizer. The diameter of PVC tube was 25 cm and 35 cm in length,and 20 cm length was impressed into field. 2 soil columns were inserted into each plot and each column was cultivated 2 clumps of plants.【Results】Compared with 100% chemical fertilizer treatment, rice grain yield is significantly increased by 6.5% in the Z+100% H treatment. Overturning the same level of green mamure and reducing 40% of chemical fertilizer (Z+60%H), the grain yield is equivalent to that of 100%H treatment. Increasing N content of rice plant significantly is found in the Z+100%H treatment at the tillering stage. And N content of stem and leaf significantly is improved by 7.0% in comparison with 100%H treatment, in particular. Although no significant difference is observed for nitrogen use efficiency of chemical fertilizer after the overturning Astragalus sinicus into paddy field, total N absorption of rice plant in the Z+100%H treatment is increased by 23.0% and 18.0% in comparison with those in the 100%H treatment at the tillering and mature periods, respectively. The above result shows green manure combined with chemical fertilizer could promote N absorption from the exogenous N sources, and differences of absorption mainly come from Astragalus sinicus’ mineralization of organic nitrogen. Total N absorption of rice plant in the Z+60%H treatment is equivalent to that in the 100%H treatment. There is a trend of increasing soil nitrogen content for different fertilization treatments. The plough soil nitrogen residual ratio is the highest in the Z+60%H treatment, with significant difference compared with the Z+100%H treatment. 【Conclusions】The 4\|year continuous overturning Astragalus sinicus significantly improve the productivity of yellow paddy fields of single\|crop rice in Fujian. To maintain the production, 40% chemical fertilizer could be replaced during the period of rice growth. One of main mechanisms of reducing fertilizer and improving efficiency is that mineralized nutrients of Astragalus sinicus replace the chemical fertilizer.
全 文 ：