陇南山区农林复合模式划分与种植结构研究

甘肃省陇南坡耕地占总耕地面积的80.15%。坡耕地及不合理的耕作方式是造成水土流失的主要原因之一,在山坡地及梯田中进行农林复合栽培,可提高土地产出率,有效防治水土流失。根据生产方式和栽培结构将陇南山区农林复合栽培的模式种类划分为林药复合、林粮间作、田间地埂利用、果菜种植、特种林粮复合、庭院经营、小流域综合治理、林草复合等8种农林复合栽培模式,以便在坡改梯、退耕还林等生态工程中较好地应用复合农林业技术。     

Traditional versus improved agroforestry systems in Vietnam: a comparison

Combined with the diverse biophysical and social heterogeneity encountered in the northern mountains, the socioeconomic changes in Vietnam that accompanied the decollectivisation process led to complex agrarian dynamics that today challenge traditional farming and management of natural resources. Data for this study were collected from villages in and around Ba Be National Park (BNP) in the Bac Kan Province located in the northern mountains of Vietnam. Traditional slash and burn cultivation is no longer a sustainable practice in Vietnam. The main challenges in the region are to protect biodiversity, maintain the land productivity and simultaneously support local livelihoods. The study shows that improved agroforestry cultivation could provide significantly higher productivity and income per unit of land, besides decreasing pressure on natural forests. The challenge to protect biodiversity is not met, as improved agroforestry implies less tree species. From an institutional and socio‐economic perspective, it is not easy for local communities to readily adapt to improved agroforestry. New systems must be tailored site‐specific to the diverse local conditions of resource‐poor farmers. Copyright © 2006 John Wiley & Sons, Ltd.     

气候变暖对西藏青稞农田氨挥发和产量的影响

【目的】研究气候变暖对西藏青稞农田氨挥发特性和青稞产量的影响,为探索减少青稞生产中的氨挥发、提高氮肥利用率提供依据。【方法】在西藏青稞主产区之一的拉萨河谷农区,采用开顶式气室(open-top chamber, OTC)增温系统模拟气候变暖进行大田试验。试验共设置不增温(对照,T0)、增温2℃(T2)和增温4℃(T4)3个处理。将290.25 kg/hm²尿素(纯N 133.5 kg/hm²)分别于播种前(4月12日)基施60%、拔节期(6月6日)和抽穗期(6月20日)各追施20%。测定不同处理青稞农田的土壤氨挥发通量以及青稞生长指标、产量及其构成要素,计算基肥和追肥的氨挥发积累量和氨挥发损失率,分析增温与土壤氨挥发特性以及青稞株高、产量及其构成要素的相关性。【结果】氮肥基施后,T0、T2和T4 3个处理的青稞农田土壤氨挥发通量至播种后第14天达到峰值,且土壤氨挥发通量峰值由大到小表现为T4>T0>T2;T2和T4处理基肥氨挥发周期均为26 d,较T0处理延长了3 d。于抽穗期追施氮肥后,T0、T2和T4 3个处理的土壤氨挥发通量...     

3株来源于青稞白酒糟醅的生防菌株鉴定及其生物活性

为寻找高效安全且来源于生物源的除草活性物质,以此为先导化合物开发生物源除草剂。从青稞白酒糟醅中分离到的菌株中筛选到3株高效除草活性菌株,经形态特征和分子生物学鉴定后,确定JZ2?1?2为多粘类芽孢杆菌,JZ2?4?5、JZ2?5?2为枯草芽孢杆菌。3株芽孢杆菌的发酵液对供试禾本科杂草野燕麦的种子萌发具有抑制作用,同时对其幼苗发育影响明显,对野燕麦幼苗根长抑制率分别为92.48%、100.00%、100.00%。枯草芽孢杆菌JZ2?4?5发酵液通过茎叶喷施后,盆栽野燕麦植株7 d后大部分死亡,JZ2?5?2、JZ2?1?2对野燕麦防除效果次之。野燕麦叶片的相对含水量、叶绿素含量均有显著降低,MDA含量和SOD酶活性也变化明显。同时证明了3株芽孢杆菌属菌株对油菜菌核病原菌具有较好的拮抗作用。作物安全性结果表明,3株芽孢杆菌属菌株对小麦、青稞安全,对油菜、蚕豆风险高。综上所述,从青稞白酒糟醅中分离到的多粘类芽孢杆菌JZ2?1?2,枯草芽孢杆菌JZ2?4?5、JZ2?5?2具有作为麦田生物源除草剂开发的潜力。     

Does pollarding trees improve the crop yield in a mature alley-cropping agroforestry system?

In agroforestry systems, the canopy of maturing trees progressively reduces the radiation available for the crop. Tree management practices such as pollarding can be used to restore the crop light availability. We monitored durum wheat, barley and pea yields during three consecutive years in an alley-cropping agroforestry system with hybrid walnut trees in Southern France. Trees have been pruned regularly to 4 m since planting (in 1995), and a section of 50 trees was pollarded at 4 m height for the first time in 2013. We measured the yields and yields components in the two different tree management systems and in a sole crop control. The non-pollarded trees reduced significantly the incident light (around 80% of the global radiation left in average) and both wheat (68% of the control) and pea (69% of the control), but not barley mean yields. In pollards inter-row, the average incident light was 98% of the total radiation the first year and the wheat yield 89% of the control. But 3 years after pollarding, the incident light was 79% of the total radiation and the pea yield was only 67% of the control. Pollarding had a transient positive impact on crop yield; after 3 years, pollards were more competitive for light than control trees. Pollarding may also reduce the belowground trees competition, but slightly, as the crop vegetative growth occurs when the trees are leafless.     

1961—2018年西藏高原青稞产区气候生产潜力时空变化特征

定量评估西藏高原青稞产区不同气候区气候生产潜力空间分布格局、演变特征及其影响机理,对于西藏高原青稞生长环境变化研究和产业可持续发展具有重要意义。基于西藏高原青稞产区不同气候区的7个典型气象站观测资料序列,采用Miami模型、Thornthwaite Memorial模型、气候倾向率、Mann-Kendall突变检验等方法,分析西藏高原青稞产区气候生产潜力时空分布特征及其对气候变化的响应。结果显示：1961—2018年青稞产区各站气温生产潜力(NPP_t)呈极显著增加趋势,降水生产潜力(NPP_r)呈显著增加趋势,蒸散生产潜力(NPP_e)和标准气候生产潜力(NPP_b)也均表现为波动的增加趋势。西藏高原主要青稞产区东部及沿雅江一带气候生产潜力限制因子为降水,高寒的北部地区气候生产潜力限制因子为气温或蒸散。NPP_t、NPP_r、NPP_e、NPP_b均表现为年代际增加趋势,20世纪80—90年代发生突变,且在21世纪初显著增加。1961—2018年气候的“暖湿型”变化趋势有利于当地青稞气候生产潜力的提高,青稞的生产不仅依赖于气候资源,还依赖于水资源的调配和利用。     

退耕还林与还草对土壤理化性质及分形特征的影响——以宁夏荒漠草原为例

以宁夏荒漠草原区为研究对象,分别选取农田、退耕还草地、退耕还林地和天然草地为研究样地,研究了退耕还林与还草对土壤理化性质及分形维数变化特征的影响。结果显示:1)土壤含水量、pH和电导率既受到退耕还林与还草措施的影响,亦受到季节变化的影响。2)农田实施退耕还林与还草工程后,退耕还草地的土壤全氮和有机碳含量最高,其平均含量分别为0.60%和5.93%。3)农田、退耕还草地、退耕还林地和天然草地的土壤黏粉粒含量分别为10.87%、7.47%、8.73%和6.53%;极细沙含量分别为39.07%、35.20%、38.87%和31.00%;细沙含量分别为29.73%、34.93%、32.80%和36.73%;粗沙粒含量分别为20.27%、21.93%、19.60%和25.73%。退耕还林地与天然草地相比土壤粒径在各粒级中均存在显著差异(P<0.05),退耕还草地与天然草地相比仅极细沙和粗沙粒含量存在显著差异(P<0.05)。4)分形维数介于1.87~2.08。土壤分形维数(D)值从高到低表现为农田(2.08)>退耕还林地(2.01)>退耕还草地(1.94)>天然草地(1.87)。5)土壤黏粉粒与土壤电导率达到正相关水平(P<0.05),与土壤碳氮比为显著负相关关系(P<0.01);土壤细沙粒与土壤pH为负相关关系(P<0.05),与电导率为显著负相关关系(P<0.01),而与碳氮比达到显著正相关水平(P<0.01);土壤分形维数与电导率达到显著正相关水平(P<0.01),与碳氮比呈显著负相关关系(P<0.01);而土壤极细沙粒和粗沙粒与各指标之间均无相关性(P>0.05)。6)土壤粒径分布分形维数与细沙粒含量呈线性负相关关系(P<0.01),而与极细沙粒含量呈线性正相关关系(P<0.01),与黏粉粒含量呈对数相关关系(P<0.01),但与粗沙粒含量未表现出相关性(P>0.05)。研究表明,在宁夏荒漠草原区实施退耕还林与还草工程,对土壤理化性质、土壤粒径分布和分形维数特征均产生一定的影响。与天然草地相比,退耕还草地中土壤有机碳和全氮含量显著提高;而退耕还林地中土壤黏粉粒、极细沙粒的分布及分形维数显著上升。说明实施退耕还林与还草工程,有利于农田退耕导致的退化区域土壤质地的改善以及退化生态系统的有效恢复。     

Bioeconomic modeling in agroforestry: a rubber-cacao example

A rubber-cacao agroforestry combination was bioeconomically modeled for a forty year cycle. A number of scenarios were simulated to find the planting densities and management strategies that achieve best production and profit levels for each situation. This example is presented to demonstrate the possibilities and advantages of a simulation approach to agroforestry modeling.

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Programación En agrosilvicultura, una combinación caucho-cacao se modeló bioeconómicamente para un ciclo de cuarenta años. Se simuló un número de guiones para hallar las densidades de plantación y estrategias de utilización que conllevan la mejor producción y niveles de aprovechamiento en cada situación. Este ejemplo pretende demostrar las posibilidades y ventajas del método de simulación en modelaciones agrosilviculturas.

     

Combinations of trees and crops in the taungya method as applied in Thailand

In Thailand the taungya reforestation method has been practiced primarily in order to rehabilitate wasteland, particularly under the Forest Village Programme. While various combinations of trees and crops are found in the taungya method on a minor scale, the major combinations are teak with upland rice in the north, fast-growing trees with cassava in the northeast, fast-growing trees with maize in the west, and para-rubber or fast-growing trees with fruit trees in the south. These combinations relate to the differences in climatic conditions, mainly the duration of the rainy season.     

中国亚热带东部地区的主要农用林业模式

在对我国亚热带东部地区的农用林业进行全面调查研究的基础上,按照国际农用林业研究委员会的农用林业分类系统,并参照有关文献,对该区现有的农用林业模式进行了分类和描述。结果表明,该区的农用林业模式种类丰富,模式的组成成分多种多样。其中有些模式规模较大,历史悠久。已经产生了巨大的社会、生态和经济效益。建议今后要加强对农用林业的研究,不断创立和优化适宜的农用林业模式。为实现农林牧副渔各业发展创造条件。