旱作水稻与花生间作系统中的氮素固定与转移及其对土壤肥力的影响

BIOLOGICAL NITROGEN FIXATION AND NITROGEN EXPORT OF GROUNDNUT INTERCROPPED WITH RICE CULTIVATED IN AEROBIC SOIL AND ITS EFFECT ON SOIL NITROGEN FERTILITY

以花生和旱作水稻为材料 ,采用分隔方法和15N同位素示踪法 ,在不同氮素水平下研究了水稻与花生间作复合体的氮素营养优势、间作花生的生物固氮效率、花生体内氮素向水稻的转移。并在田间条件下研究了花生单作、水稻单作、水稻 /花生间作 3种栽培方式下对土壤氮素肥力的影响。结果表明 :( 1 )水稻和花生间作有产量优势和氮素营养优势 ,在N 0kghm- 2 、N 2 2 5kghm- 2 和N 3 0 0kghm- 2 三个氮素水平下 ,根系不分隔的水稻生物量分别比分隔处理的高 3 0 0 3 %、1 0 1 %和 2 2 % ;水稻氮素吸收量分别比分隔处理的高 74 0 3 %、1 6 93 %和 2 3 2 % ;( 2 )花生在N 2 2 5kghm- 2 和N 3 0 0kghm- 2 氮素水平下 ,分隔处理和不分隔花生固氮量分别为 3 8 1 1 %、40 97%和 1 4 81 %、2 0 49% ,间作能提高花生固氮效率 ;( 3 )花生体内氮素在共生期内可以转移到水稻体内 ,花生固氮量和氮素转移没有相关 ;( 4 )与水稻单作比较 ,花生 /水稻间作可以改善土壤的氮素营养。

With root partition method and 15N-isotope dilution method, field and pot experiments were conducted to examine the research included the effects of intercropping of rice cultivated aerobic soil and groundnut on dry matter production, quantity of nitrogen uptake, biological nitrogen fixation, and nitrogen transfer from groundnut to rice at three nitrogen level, namely 0, N 225 kg hm -2, N 300 kg hm -2. Soil nitrogen fertility was also investigated under the new cultivation system. The results show that 1) there was a yield advantage in the new intercropping system compared to monocrop rice. The dry matter, for example, of rice in intercropping at three nitrogen application rates were 30.03%, 10.1%, 2.2% higher than those in monocropping, respectively, and the same situation happened for the nitrogen uptake. 2) Biological nitrogen fixation estimated by 15N-isotope dilution method in groundnut decreased with the increase nitrogen level while intercropping can improve biological nitrogen fixation of groundnut. 3) N-transfer from groundnut to rice was evident but no co-relation between biological nitrogen fixation and nitrogen transfer was found in this experiment. 4) Intercropping system could increase significantly the mineral nitrogen during the whole growth stage, thus improving soil nitrogen fertility.