杉木-山苍子-作物复合经营模式土壤肥力的研究

通过对杉木-山苍子(A)、杉木-山苍子-黄豆(B)、杉木-山苍子-烟叶(C)及对照的纯杉林土壤生物学活性、土壤化学性质、土壤结构、孔隙组成和水分性状等研究,结果表明:模式B、C表层土壤结构性状变差,土壤营养元素含量下降,土壤生物学活性减弱,但底层土壤熟化程度提高。为了维持幼林地土壤肥力,模式B、C应适当降低耕作强度,缩短间种年限,同时适当增加N和P肥使用量。模式A具有良好的改良土壤能力,是南方林区优良的杉木混农模式。     

Indigenous agroforestry of Pohnpei

Plant species and cultivars of the indigenous agroforestry system of Pohnpei were surveyed in transects through 54 randomly-selected farms. The agroforestry system was characterized by extensive cultivation of yams (Dioscorea), aroids (Alocasia), and Piper methysticum under a permanent overstory of breadfruit, coconut, and forest remnant trees and a middle canopy of Hibiscus tiliaceus, Musa spp., and Morinda citrifolia. In the 10 ha of survey plots, 161 species were found, of which 102 were trees, shrubs, and crops and 59 were uncultivated herbaceous plants. Numbers of tree, shrub, and crop species per farm ranged from 16 to 37 with an average of 26. Twenty-eight breadfruit and 38 yam cultivars were found in the survey plots, showing that cultivar diversity is an important component of the biological diversity maintained and utilized in Pohnpeian agroforests.     

Rooting systems of western and southern African Faidherbia albida (Del.) A. Chev. (syn. Acacia albida Del.) —a comparative analysis with biogeographic implications

Faidherbia albida is a well-known and widespread agroforestry species of the Sudano-Sahelian zone of West Africa. Recent collection and testing efforts have included attempts to introduce seed origins from eastern and southern Africa into the Sahel. These have generally met with failure. Despite superior early growth, mortality is severe by the first or second year. Trials conducted at the ICRISAT Sahelian Center in Niger have demonstrated that this is probably due to differences in rooting patterns between southern and western Africa origins. A separation of the species into two ecotypes, i.e., upland (western Africa) and riparian (eastern, southern and southwestern Africa) is proposed. Based on this argument, the Sudan/Ethiopia region is identified as a possible center of origin for the species. Submitted as ICRISAT Journal Article # JA-1107.     

Economic contribution of participatory agroforestry program to poverty alleviation: a case from Sal forests, Bangladesh

In the Forest Department of Bangladesh, a Participatory Agroforestry Program (PAP) was initiated at a denuded Sal forests area to protect the forest resources and to alleviate poverty amongst the local poor population. We explored whether the PAP reduced poverty and what factors might be responsible for poverty alleviation. We used three poverty measurement methods: the Head Count Index, the Poverty Gap Index and the Foster-Greer-Thorbecke index to determine the extent poverty reduction. We used a linear regression model to determine the possible differences among factors in poverty reduction. Data were collected through semi-structured questionnaires and face to face interviews within the study area. PAP proved effective at poverty alleviation, considerably improving the local situation. The linear regression model showed that PAP output explained the income differences in poverty reduction. Participants identified bureaucracy and illegal money demands by forest department officials, an uncontrolled market system, and underdeveloped road infrastructure as the main obstacles to reduction of poverty. Overall, PAP is quite successful in alleviating poverty. So this program might be ofinterest at other degraded forest areas as a tool to alleviate poverty.     

毛竹雷公藤混农经营技术与固土保水功能

连续7 a毛竹雷公藤混农经营试验表明,采取“中间带状”混农经营模式种植雷公藤,毛竹林的密度应控制在2100-2400株.hm-2。该密度不仅利于笋用林和笋竹两用林的经营,还使雷公藤平均基径增粗23.3%,平均支数增加20%。混农经营的林分由于雷公藤的覆盖,毛竹林地免遭雨水直接袭击,此外,雷公藤落叶与宿根还有保持水土,改良土壤的作用。与毛竹纯林相比,混农经营地土壤结构和水分性状得到一定程度的改良,表土层>0.25 mm的水稳性团聚体含量增加3.17%,结构体破坏率降低4.51%,土壤持水量增加37.4%,水源涵养量增加736.513 t.hm-2。     

控制棉铃虫猖獗危害的区域性综合防治关键技术体系的研究

在跟踪推广应用“六五”以来所形成的综防技术基础上,进一步研究改进关键技术、加强病虫监测预报、组建综防技术体系。在1992、1993年棉铃虫猖獗发生的情况下,于河南省新乡棉花病虫害综防示范区0.67万hm#+2棉田上实施后,有效控制了棉铃虫危害。这套控制棉铃虫猖獗危害综合防治关键技术主要是：研究改进了棉铃虫中期预报方法;提出“一代监测、二代保顶、三代保蕾、四代保铃”为主的防治策略;制定推广适用于不同世代、不同水肥条件的科学防治指标;协调应用多种配套措施保护、利用自然天敌控害;系统监测和治理害虫抗药性;利用棉花种质资源和品种的抗病虫性;诱杀成虫;组建大面积综防技术体系。     

黄土高原林农复合生态系统建造模式及效益的研究

当今林农复合生态系统的研究已受到许多国家的重视。本文提出发展能源林,解决黄土高原农村能源问题,可实行林农牧相结合的技术方针,即建立以沙棘、山桃、柠条、刺槐等能源林树种为主居于上层空间,在下层以带状或行间配置粮、油作物或牧草等,组成林农复合生态系统的建造模式,以提高能源林的生物产量、经济效益以及土地利用率。     

淳化泥河沟流域农林复合生态经济系统优势分析

尝试用灰色关联分析方法,以农业总产值、林果业产值、粮食单产、人均纯收入为母因素,对淳化泥河沟流域农林复合生态经济系统森林覆盖率等１１个影响因素的影响程度进行了优势分析和排序,得出：苹果面积＞林果业收入＞治程度＞商品率＞养殖业收入＞有机肥投入＞无机肥投入＞年降水量＞森林覆被率＞工副业收入＞种植业收入。分析认为农林复合生态经济系统的建设是黄土残原沟壑区农业“两高一优”持续发展和农村经济发展的主要途径之一和发展方向,林果业、治理度和商品率是影响该系统的三要素。     

海岸带农林复合系主要植物的养分含量和分配

对海岸带农林复合系统中的池杉、青秆竹、水稻、甘蔗等主要植物种类和生物量与元素组成进行研究。结果表明：６年生池杉林分、青秆竹林分均是叶的养分元素含量最大,树干的最小;其养分元素积累量分别为２６８９．４８１和３２９７．４４２ｋｇ／ｈｍ＾２,其养分元素各界量排序分别为Ｎ〉Ｃａ〉Ｍｇ〉Ｋ〉Ｃｌ〉Ｎａ〉Ｐ、Ｋ〉Ｃｌ〉Ｎ〉Ｍｇ〉Ｃａ〉Ｐ〉Ｎａ;水稻（杂优）、甘蔗的养分元素各界量分别为１１８６．０８３、１１６１     

晋西黄土区常规果农间作模式下 果树遮阴时空分布特征

为探讨晋西黄土区常规苹果树与农作物间作模式条件下不同树龄果树遮阴范围的时空分布特征,提出合理的间作作物种植区域,以山西吉县果农间作条件下4~7 a生苹果树为试验材料,遵循平行光线下的相似性原理,将果树按其树体缩小50倍,制作不同林龄的苹果树3D模型,利用树体模型在研究区进行果树遮阴范围的动态测定。结果表明：（1）在时间上,单株苹果树遮阴面积在一天内随时间先减小后增大,中午12∶00果树遮阴面积最小;在空间上,苹果树遮阴范围整体呈现不等宽弧型分布,且果树北侧遮阴大于南侧遮阴距离0.5~0.6 m。（2）在一天中,4~7 a生苹果树行间均受到同行苹果树(目标果树与邻株果树)的叠加遮阴,遮阴时长为4~9 h。（3）4 m×5 m株行距配置下间作作物的适宜种植区域为1.41~1.91 m,5 m×5 m 株行距配置下间作作物的种植区域为1.63~2.14 m,且种植区域均随树龄的增加而减小。（4）间作作物行间适宜种植区域应采用南北向不等间距种植,并且适宜种植区北向距离大于南向距离0.6~0.7 m。综合研究区常规果农间作配置果树遮阴范围时空分布特征分析,传统果农间作系统下不同树龄时期,间作作物的南北方向等间距种植模式存在不合理性。本研究依据晋西黄土区常规果农间作配置模式果树遮阴范围时空分布特征,提出果农复合系统间作作物的不同株行距配置下不同树龄的间作作物合理种植区,间作作物种植需考虑南北不等间距,且随着树龄增长间作范围应不断缩小。