【作者】 王志刚；

【导师】 李隆；

【作者基本信息】 中国农业大学 ， 植物营养， 2014， 博士

【摘要】 间套作在生产中广泛应用,具有生产力和养分利用优势。间套作在高生产力和高养分量携出条件下,土壤肥力是否维持或者降低成为众所关注的问题。然而,连续间套作条件下土壤肥力变化及其受作物组合和施肥影响仍缺乏系统研究。因此,在甘肃武威白云试验站进行两个间套作定位试验研究不同作物间作组合以及不同施磷水平对土壤肥力(物理、化学和生物)的影响。定位试验一始于2003年,试验处理包括三种间作作物组合(小麦/玉米、蚕豆/玉米及小麦/蚕豆间作连作和间作轮作)；四种轮作(小麦-玉米、小麦-蚕豆、蚕豆-玉米和小麦-蚕豆-玉米)以及三种连作(连作玉米、小麦和蚕豆)。定位试验二始于2009年,试验为裂区设计,主因素为不同施磷水平(0、40和80kg P/ha),副因素为4种间作模式(玉米/蚕豆、玉米/大豆、玉米/鹰嘴豆和玉米/油菜间作)和相应5种单作(单作玉米、蚕豆、大豆、鹰嘴豆和油菜)。在定位试验一的第9年(2011年)和第10(2012年)年,定位试验二的第3年(2011年)和第4(2012年)年,分别测定作物生产力和养分吸收量及土壤肥力变化。土壤肥力特征从物理(入渗率、土壤机械组成、紧实度、水稳性团聚体含量)、化学(有机质、全氮、Olsen P含量、速效钾、阳离子交换量和pH值)和生物学(脲酶、酸性磷酸酶、硝酸还原酶和蔗糖酶活性)性质进行研究。主要研究结果如下：(1)间作具有明显产量和养分吸收量优势。试验一,小麦和玉米,蚕豆和玉米及小麦和蚕豆三种作物组合平均下,两年间间作连作生产力比相应作物连作和轮作分别提高5.2-29.5%和2.9-12.8%；间作轮作比连作和轮作分别增加14.1-33.3%和11.6-16.2%均达到显著水平。三种作物组合平均下,两年里间作连作地上部氮吸收量分别比相应作物连作和轮作提高0-15.4%和4.4-9.8%,间作轮作比相应作物连作和轮作增加8.4-22.1%和12.7-16.1%,间作连作地上部磷吸收量比相应作物连作和轮作增加0-14.4%及0-10.5%,间作轮作比相应作物连作和轮作提高3.7-17.4%和7.3-13.1%；间作连作地上部钾吸收量比相应作物连作和轮作提高0-14.3%及0-20.4%,间作轮作比相应作物连作和轮作增加6.1-21.7%及2.3-28.3%均达到显著水平。试验二,三个磷水平平均而言,两年间蚕豆压米,大豆/玉米,鹰嘴豆/玉米及油菜/玉米间作比相对应单作分别增产14.5-19.6%,19.3-38.2%,20.7-24.3%及24.8-38.6%。两年间,间作地上部氮吸收量比对应单作分别增加19.2-20.7%,2.2-27.5%,24.8-26.5%以及29.4-39.7%；磷吸收量提高16.3-27.3%,2.4-30.6%,28.1-35.1%和36.9-40.7%,钾吸收量增加21.5-31.9%,9.7-52.9%,31.5-38.1%和43.1-49.2%。(2)间作改善了土壤物理性状。试验一在第9年(2011年)作物收获后,大于2mm土壤水稳性团聚体含量,蚕豆和玉米间作连作高于相应两作物的连作和轮作175%和105%,差异达到显著水平；间作轮作高于连作和轮作75%、65%,同样达到显著水平；在第10年(2012年),小麦和玉米间作连作高于相应两作物的连作和轮作188%和130%,小麦和玉米间作轮作高于连作和轮作138%和174%；蚕豆和玉米间作连作高于连作和轮作474%、450%,间作轮作高于连作和轮作135%、125%,均达到显著差异。2-0.25mm水稳性团聚体含量,2011年小麦和玉米连作和轮作分别比间作连作增加36.9%和44%,比间作轮作增加16.2%和22.1%；2012年蚕豆和玉米间作2-0.25mm土壤水稳性团聚体含量与相应连作和轮作相比,没有显著差异；蚕豆和小麦间作连作和间作轮作显著高于轮作。0.25-0.106mm和小于0.106mm土壤水稳性团聚体在每个作物组合下不同种植方式间均没有差异。种植方式对土壤容重、机械组成(沙粒、粉粒和粘粒组成)及紧实度没有显著影响；2011年间作连作和2012年轮作(小麦和玉米组合除外)显著提高土壤饱和入渗率。试验二,三个磷水平平均而言,蚕豆/玉米,大豆/玉米和油菜/玉米间作土壤饱和入渗率比相应单作分别提高91-131%,31.1-39.4%和9.6-25.6%。大于2mm水稳性团聚体含量,蚕豆/玉米,大豆/玉米,鹰嘴豆/玉米和油菜压米间作比相应单作分别提高12.2-17.4%,0-46.7%,19.6-39.2%和0-34.6%;2-0.25mm,0.25-0.106mm和小于0.106mm水稳性团聚体在间作和单作之间没有变化。土壤机械组成和紧实度间作相对于单作没有显著变化。因此,间作具维持或改善土壤物理性状的潜力。(3)间作维持土壤化学性状基本稳定。试验一,与连作和轮作相比,间作连作和间作轮作下土壤有机质、全氮、Olsen P、速效钾和阳离子交换量没有显著变化(2011年小麦/玉米和蚕豆压米间作土壤pH和2012年土壤速效钾和阳离子交换量除外)。试验二,三个磷水平平均而言,除2012年鹰嘴豆/玉米以及两年油菜/玉米间作外,土壤有机质在间作和单作之间没有差异；两年间土壤全氮含量在单作和间作之间均对施磷水平没有响应(2011年80kg P ha-1下蚕豆/玉米间作除外)；2012年间作降低土壤Olsen P含量,2011年和2012年土壤速效钾均降低,2012年土壤阳离子交换量和pH有降低趋势。施磷缓解土壤Olsen P下降。(4)间作保持土壤生物学性状稳定。试验一,2011年小麦/玉米间作和2012年小麦/蚕豆间作土壤脲酶显著高于连作和轮作,土壤酸性磷酸酶、硝酸还原酶和蔗糖酶活性没有显著变化。试验二,三个磷水平平均而言,两年间,除间作土壤酸性磷酸酶活性高于对应单作,土壤脲酶、硝酸还原酶和蔗糖酶活性没有受到种植方式的影响。(5)温室模拟试验表明,土壤中大于2mm,2-0.25mm和0.25-0.106mm水稳性团聚体含量与作物生产力显著相关。通径分析发现土壤中大于2mm,2-0.25mm和0.25-0.106mm水稳性团聚体含量直接通径系数为-0.14,0.21和0.42,0.25-0.106mm水稳性团聚体对作物生产力影响显著。土壤物理性状解释40%作物生产力变化。更多还原

【Abstract】 Intercropping is widely practised in agriculture because of its significant overyielding and nutrition acquisition advantages. Under this conditions whether soil fertility sustained or improved became a hot spot, which is well-known. However, there are few published studies about continuous intercropping on long-term changes in soil fertility. Therefore, we conducted two field experiments about the effects of intercropping systems and P application rates on soil fertility in Baiyun village, Wuwei City, Gansu Provience in northwest China. The first long-term field experiment was carried out in2003, the treatments included three intercropping systems (wheat (Triticum aestivum L. cv. Yongliang No.4)/maize(Zea mays L. cv. Zhengdan No.958), faba bean (Vicia faba L. cv. Lincan No.5)/maize and wheat/faba bean continuous and rotational intercroppings), four rotational systems (wheat-maize, wheat-faba bean, faba bean-maize and wheat-faba bean-maize), monoculture systems (monocropping maize, wheat and faba bean). The second long-term field experiment was conducted in2009which was a split-plot design, with different rates of P fertilizer (0,40and80kg P/ha) as main plot and four intercroppings (maize(Zea mays L. cv. Zhengdan No.958)/faba bean (Viciafaba L. cv. Lincan No.5)),(maize/soybean(Glycine max L.cv. Wuke No.2)),(maize/chickpea (Cicer arietinum L. cv. Longying No.1)) and (maize/turnip (Brassica campestris L.cv. Gannan No.4)) and five monocultures (maize, faba bean, soybean, chickpea and turnip) as sub-plot. We measured crop yields, above ground nutrient uptake and soil fertility in the9th (2011) and10th (2012) for the first experiment and in the3th (2011) and4th (2012) for the second experiment, respectively. Soil fertility properties included physical (soil saturation infiltration, soil particle composition, soil compaction and soil water stable aggregates concentration), chemical (soil organic matter, total N, Olsen P, available K, cation exchangeable capacity and pH) and biological properties (soil urease, acid phosphatase, nitrate reductase and sucrase activities). The main results were as follows:(1) Continuous intercropping still were overyielding and had nutrient acquisition advantage. In the first field experiment, averaged over wheat and maize, faba bean and maize, and wheat and faba bean crop combinations, crop productivity was enhanced by5.2-29.5%and2.9-12.8%in continuous intercropping; and increased by14.1-33.3%and11.6-16.2%in rotational intercropping in comparison with corresponding monoculture and rotation cropping systems over two years, respectively. N acquisition by above ground parts in continuous intercropping was increased by0-15.4%and4.4-9.8%, and in rotational intercropping by8.4-22.1%,12.7-16.1%compared to corresponding monoculture and rotational crops, respectively. P acquisition in continuous intercropping was enhanced by0-14.4%and0-10.5%, and rotational intercropping by3.7-17.4%and7.3-13.1%compared to the weighted means of monoculture and rotational crops, respectively. The percentages of K acquisition were raised by0-14.3%,0-20.4%in continuous intercropping,6.1-21.7%and2.3-28.3%in rotational intercropping, respectively.In the second field experiment, averaged over three P application rates, faba bean/maize, soybean/maize, chickpea/maize and turnip/maize intercroppings were overyielded by14.5-19.6%,19.3-38.2%,20.7-24.3%and24.8-38.6%, respectively, compared to corresponding monocultures across two years. N acquisition by above ground parts in intercropping was enhanced by19.2-20.7%,2.2-27.5%,24.8-26.5%and29.4-39.7%; P acquisition was raised by16.3-27.3%,2.4-30.6%,28.1-35.1%and36.9-40.7%; K acquisition was increased by21.5-31.9%,9.7-52.9%,31.5-38.1%and43.1-49.2%compared with corresponding monocultures across two years, respectively.(2) Intercropping improved soil physical properties. In the9lh (2011) years after crops harvest, soil concentration of water stable aggregates with greater than2mm in soil grown faba bean/maize intercropping were175%and105%higher for continuously intercropping,75%and65%higher for rotational intercropping than corresponding monocultre and rotation crops, respectively. In the10th (2012) years, soil concentration of water stable aggregates with greater than2mm in soil grown wheat/maize intercropping were188%and130%higher for monoculture and rotation crops, respectively. Soil concentration of water stable aggregates with greater than2mm in soil grown wheat/maize intercropping were138%and174%higher for rotational intercropping, respectively. Soil concentration of water stable aggregates with greater than2mm in soil grown faba bean/maize intercropping were474%and450%,135%and125%greater for continuous and rotational intercropping, respectively. In2011, soil concentration of2-0.25mm water stable aggregates in soil grown monoculture and rotation were36.9%and44%,16.2%and22.1%higher for continuous or rotational intercropping, respectively. In2012, soil concentration of2-0.25mm water stable aggregates were no differences among monoculture or rotational and intercropping, but rotational was greater than faba bean/wheat intercroppings. Soil concentration of0.25-0.106mm and smaller than0.106mm water stable aggregates were not affected by intercropping. Intercropping were not influenced on soil bulk density, texture and compaction. Soil infiltration were altered by continuous intercropping in2011and rotation in2012(with an exception of wheat with maize combination) in the long-term experiments.In the second field experiment, averaged over three P rates, soil infiltration were increased by91-131%,31.1-39.4%and9.6-25.6%in faba bean/maize, soybean/maize and turnip/maize intercropping, compared to corresponding monocultures across two years. Soil water stable aggregates with greater than2mm for faba bean/maize, soybean/maize, chickpea/maize and turnip/maize intercropping were improved by12.2-17.4%,0-46.7%,19.6-39.2%and0-34.6%compared with corresponding monocultures over two years. There were no significant differences in2-0.25mm,0.25-0.106mm, smaller than0.106mm soil aggregates, soil texture and compaction between intercropping and monoculture. Thus, soil physical properties were maintained or improved by intercropping.(3) Generally, soil chemical properties were sustained by intercropping. In the first experiment, Soil organic matter, total N, Olsen P, available K and cation exchangeable capacity were not as affected by intercropping (with an exception of soil pH in wheat/maize and faba bean/maize intercropping in2011and cation exchangeable capacity in2012). In the second experiment, averaged over P rates, soil OM were stable with an exception of chickpea/maize intercropping in2011and turnip/maize intercropping both two years. Interestly, there were no responses of soil total N to P application under both intercropping and monoculture (with an exception of faba bean/maize intercropping at80kg ha-1in2011); soil Olsen P was reduced by intercropping in2012; soil available K significantly decreased by intercropping in both years; soil cation exchangeable capacity and pH demonstrated a declined trends in2012. Soil Olsen P reduced by intercropping, which can be alleviated by P added.(4) Intercropping maintained soil biological properties. In the first experiment, soil urease activity in wheat/maize intercropping in2011and wheat/faba bean intercropping in2012were greater than corresponding monoculture and rotation, but soil acid phosphatase, nitrate reductase and sucrase activities were stable. In the second experiment, in the majority of cases soil enzymes activities did not differed across all the cropping systems at different P application rates compared to monocrops with the exception of soil acid phosphatase activity which was higher in intercropping than in the corresponding monocrops in both years, indicating that intercropping enhanced utilization of organic P in soil via altered soil acid phosphatase.(5) The greenhouse experiment demonstrated that soil water stable aggregates>2mm,2-0.25mm and0.25-0.106mm were significantly correlated with crop productivity. The path coefficients were-0.14,0.21and0.42, respectively, and were significantly in0.25-0.106mm. The determination coefficient (R2) is0.40indicated soil physical properties which explain40%the variation of productivity.更多还原