CAJ | 학술논문

旱作春小麦(Triticum aestivum L.)是西部黄土高原最重要的禾谷类作物,该区苜蓿(Medicago sativa L.)分布也非常广泛.持续的作物连作和多年苜蓿种植系统都存在很多问题.雨养农业系统发展的关键是最佳水分利用策略的应用.发展合理的苜蓿-小麦轮作系统对该区农业的发展有十分重要的意义.由于苜蓿终止时间严重影响土壤水分,所以在适宜的时间终止苜蓿就显得十分重要.然而,关于苜蓿-小麦轮作中老苜蓿在一年中适宜终止时间的研究鲜见报道.本研究利用黄土高原西部典型的半干旱雨养农业区30年老苜蓿布设田间试验,旨在探索老苜蓿地土壤水分状况、苜蓿终止时间和少量氮肥施用对系统生产力及土壤水分的影响.结果表明,长期种植苜蓿后0~3 m土壤水分很少,即便遇到丰水年(2003年),3年的时间都不足以恢复土壤水分.30年苜蓿在一年中春季还是秋季终止对土壤水分状况无显著影响.种植苜蓿30年后杂草竞争力增强,苜蓿干物质和产量水平都相当低,且对1 kg hm-2的氮肥使用无明显响应.由于土壤水分含量太低,后茬春小麦对1 kg hm-2的氮肥使用和苜蓿终止时间也无明显响应.因此,苜蓿持续种植时间太长会耗竭土壤水分,使后茬春小麦对苜蓿在一年中的终止时间及少量的氮肥使用无响应,需要3年以上时间才有可能恢复土壤含水量.
한작춘소맥(Triticum aestivum L.)시서부황토고원최중요적화곡류작물,해구목숙(Medicago sativa L.)분포야비상엄범.지속적작물련작화다년목숙충식계통도존재흔다문제.우양농업계통발전적관건시최가수분이용책략적응용.발전합리적목숙-소맥륜작계통대해구농업적발전유십분중요적의의.유우목숙종지시간엄중영향토양수분,소이재괄의적시간종지목숙취현득십분중요.연이,관우목숙-소맥륜작중로목숙재일년중괄의종지시간적연구선견보도.본연구이용황토고원서부전형적반간한우양농업구30년로목숙포설전간시험,지재탐색로목숙지토양수분상황、목숙종지시간화소량담비시용대계통생산력급토양수분적영향.결과표명,장기충식목숙후0~3 m토양수분흔소,즉편우도봉수년(2003년),3년적시간도불족이회복토양수분.30년목숙재일년중춘계환시추계종지대토양수분상황무현저영향.충식목숙30년후잡초경쟁력증강,목숙간물질화산량수평도상당저,차대1 kg hm-2적담비사용무명현향응.유우토양수분함량태저,후치춘소맥대1 kg hm-2적담비사용화목숙종지시간야무명현향응.인차,목숙지속충식시간태장회모갈토양수분,사후치춘소맥대목숙재일년중적종지시간급소량적담비사용무향응,수요3년이상시간재유가능회복토양함수량.
Rainfed spring wheat (Triticum aestivum L.) is the most important cereal crop on the Western Loess Plateau. Lucerne (Medicago sativa L.) has been very popular. There are problems associated with both continuous cropping and with perennial lucerne systems. The key challenge for rain-fed cropping systems is to adopt strategies that make optimal use of water. Developing lucerne-wheat rotation systems will have significant benefits for agriculture development on the Loess Plateau, nevertheless, it is very important to terminate lucerne at the right time as it affects soil moisture. However, very little research has been done on the timing for termination of old lucerne in the semiarid areas of the Western Loess Plateau. Based on field experiments conducted in a typical semiarid area on the Western Loess Plateau, this paper aimed to investigate the soil water and termination timing of 30 years old lucerne on the productivity of lucerne-wheat rotation. The results showed that the soil profile after long-term lucerne was very dry down to 3 meters, the three year experiment period was not sufficient to allow soil water recharge, even after a high rainfall year. Time of 30 years old lucerne removal (in spring or later in the year) had no significant effect on soil water regimes. As a result, weeds became more competitive, the old lucerne stand showed poor dry matter, yield, had no response to 1 kg ha-1 of N application, and was overdue for termination. Following spring wheat made no response to 1 kg ha-1 of N fertilizer due to dry soil profile after 30 years lucerne growing.