花生-南酸枣间作系统氮素利用研究

在低丘红壤花生—南酸枣间作系统中利用1 5N同位素示踪方法研究结果表明 ,5龄和 9龄南酸枣分别竞争利用了施用于花生的氮肥的 9 66%和 3 0 15 %。与单作花生系统相比 ,5龄和 9龄南酸枣间作系统中花生对表施氮肥的利用率分别下降 3 7 8%和 5 9 1%。间作 5龄南酸枣对模拟淋溶至亚表层土壤氮素的利用率非常低下 ,与花生单作相比 ,5龄南酸枣间作系统表施氮素土壤残留没有显著差异 ,其安全网作用不明显。随着树龄增加 ,南酸枣根系充当安全网作用的潜力被证实。 9龄南酸枣对模拟淋溶至3 5cm和 5 5cm深度土壤氮素的利用率分别为 3 3 79%和 14 74% ,与花生单作相比 ,其表施氮素在 0～ 60cm土层残留降低 2 4 1%。

N RECOVERY IN CHOEROSPONDIAS AXILLARIS AND PEANUT(ARACHIS HYPOGAEA) ALLEY CROPPING SYSTEMS ON UDIC FERROSOL IN SUBTROPICAL CHINA

¹⁵N-labell fertilizer was used to study on N competition between tree and peanuts,and to test the potential of tree roots acting as safety-net on Choerospondias axillaris cropped with peanut(Arachis hypogaea) in subtropical China.Five-year-old and nine-yea-rold Choerospondias axillaris recovered 9.66% and 30.15% of the N applied at topsoil of peanut area,respectively.Compared with sole peanut system,N recovery by peanut was decreased by 37.8%in 5-year-old and 59.1% in 9-yea-rold Choerospondias axillaris alley cropping system,respectively.The role of 5-yea-rold Choerospondias axillaris acting as a safetynet was not obvious,since it recovered little N from subsoil and did not decrease N residual in the soils. With increasing tree age,9-yea-rold Choerospondias axillaris showed its potential to act as a safety-net, since it recovered 33.79% N from 35cm soil layer and 14.74% N from 55 cm soil layer,respectively,and N residual in 0~60 cm soil layer was decreased by 24.1%,compared with that in sole peanut system.