小麦/蚕豆间作系统中施氮对小麦氮营养及条锈病发生的影响

Effect of Nitrogen Addition on Nitrogen Nutrition and Strip Rust Occurrence of Wheat in Wheat/Fababean Intercropping System

小麦/蚕豆间作在云南较普遍,而条锈病是小麦的主要病害。为研究小麦氮营养及条锈病发生,在云南玉溪和陆良两地同时布置田间试验,在小麦单作(Wm)、小麦/蚕豆间作(Wi)和小麦/蚕豆间作且覆膜隔根(Wp)3种植方式中对小麦设0、150、300kg·hm-2(分别N0、N150、N300)3个氮水平处理,测定了小麦叶片氮含量和条锈病病情指数,结果表明:(1)不论是单作小麦(Wm)还是间作小麦(Wp或Wi),施氮(N150和N300)比不施氮(N0)都显著提高了小麦叶片氮含量,但N150与N300间小麦叶片氮含量差异不显著;综合Wm、Wp、Wi不同种植方式,两地小麦叶片氮含量都随施氮量增大而显著提高(P<0.0001),N150、N300分别比N0提高了52.7%、74.1%,N300比N150提高了14.0%。(2)在相同氮用量下,Wm、Wp、Wi间的小麦叶片氮含量只在玉溪点N0条件下Wp和Wi比Wm有显著提高(增加52.3%),而玉溪点N150、N300以及陆良点N0、N150、N300下都没明显差异。(3)施氮对小麦条锈病的影响在玉溪和陆良两地表现不同,在玉溪,施氮对小麦条锈病病情指数有增加作用,小麦条锈病病指与叶片氮含量间呈显著正相关;而在陆良,不同种植方式下N150和N300的小麦条锈病病指比N0都有显著降低,N150与N300间差异不显著,小麦条锈病病指与叶片氮含量间的最优回归曲线显示小麦条锈病病指先随叶片氮含量升高而显著降低,达最低点后,又随叶片氮含量升高而呈增加趋势。(4)Wp和Wi发病中期的小麦条锈病病指相比Wm降低了10.9%,但发病盛期时降低微弱。总的结果表明,在本田间试验条件下,小麦蚕豆间作只在缺氮时对小麦氮营养有改善作用,小麦蚕豆间作相对单作对小麦条锈病有一定的控制效果,但小麦蚕豆根系相互作用对小麦氮营养及小麦条锈病病指无明显影响;氮肥施用显著改善了小麦氮营养,小麦条锈病发生既受氮营养的影响,又可能与品种特性、种植方式、环境条件等多因素有关。

The wheat/fababean intercropping system is widespread in Yun＇nan province,and strip rust is the main disease for wheat.In order to assess wheat nitrogen nutrition and strip rust occurrence,two field experiments were conducted simultaneously at Yuxi and Luliang spots in Yan＇nan Province.Three nitrogen（N） level namely 0,150 and 300kg·hm-2（marked as N0、N150、N300）were set for wheat as experimental treatments in three cropping patterns as wheat monoculture（Wm）,wheat/fababean intercropping（Wi） and wheat/fababean intercropping with plastic film separation between wheat and fababean roots（Wp）,leaves N concentration（LNC） and strip rust disease index（SRDI） of wheat surveyed during the period of disease occurrence.The results obtained were as follows：（1） Not only for Wm,but also for Wp and Wi,LNC of wheat in N application treatments（N150,N300） increased significantly relative to no N addition（N0）,while there was no significant difference between N150 and N300;Compositing Wm、Wp and Wi different cropping patterns LNC of wheat at two spots improved markedly with increasing N rates（P0.0001）,i.e.LNC of wheat in N150、N300 increased by 52.7%、74.1% compared with that of N0,respectively and that of N300 increased by 14.0% compared with N150.（2）Under the same N rate,only under N0 at Yuxi spot wheat LNC of Wp and Wi significantly increased（by 52.3%）compared with Wm,and there were no obvious difference among Wm、Wp、Wi under N150,N300 at Yuxi spot and under N0,N150,N300 at Luliang spot.（3）The effect of N addition on wheat strip rust were not alike between at Yuxi spot and at Luliang spot.At Yuxi spot N use actually promoted wheat SRDI,and there was a clear positive correlation between wheat LNC and SRDI.However,at Luliang spot,wheat SRDI under N150 and N300 decreased significantly compared with that under N0,but no substantial difference between N150 and N300;The best-fit regression curve indicated that wheat SRDI first significantly decreased and then had a rise trend with the increasing of wheat LNC.（4）Wheat SRDI of Wp and Wi decreased by 10.9% at the intermediate degree of the disease but only feebly decreased at the vigorous period compare to Wm.The total results demonstrate that under the current experimental condition whea/fababean intercrop could improve wheat N nutrition only when N deficiency and had certain control effect on wheat strip rust comparing to wheat monoculture,but there were no marked effect of roots interaction between wheat and fababean on wheat N nutrition and SRDI;N fertilizer utilization remarkably promoted wheat N nutrition.Wheat strip rust occurrence in wheat/fababean intercropping system was not only affected by N nutrition,may be also related with many factors such as characteristic of cultivars,planting patterns and environmental conditions.