不同前茬作物与种植密度对大蒜农艺性状的影响

为研究不同前茬作物和种植密度对大蒜生长发育的影响,通过设定大豆茬(A1)、谷子茬(A2)和不同密度(M1、M2)两因素试验,测定不同处理的大蒜农艺性状指标和产量。试验结果表明,大蒜的农艺性状指标A1处理高于A2处理,M2处理高于M1处理,处理间产量没有显著差异。在生产中可以通过优化前茬作物和种植密度来提升大蒜商品性。     

Ecological weed management by cover cropping: effects on weed growth in autumn and weed establishment in spring

Cover crops grown in the period between two main crops have potential as an important component of a system‐oriented ecological weed management strategy. In late summer and autumn, the cover crop can suppress growth and seed production of weeds, whereas the incorporation of cover crop residues in spring may reduce or retard weed emergence. Based on these two criteria, six cover crop species were evaluated for their weed suppressive potential in 2 years of experimentation in the Netherlands. Fodder radish, winter oilseed rape and winter rye had the strongest competitive ability in autumn; the competitive strength of Italian ryegrass was intermediate and white lupin and lucerne were poor competitors. Competitiveness was strongly correlated to early light interception. Surprisingly, doubling the recommended sowing density did not increase weed suppressive ability. Although a poor competitor in the fall, after incorporation in spring, lucerne had the strongest inhibitory effect on seedling establishment, followed by winter oilseed rape and white lupin. Winter rye and fodder radish did not affect seedling establishment, whereas Italian ryegrass was not evaluated because of re‐growth after incorporation. Competition in autumn and subsequent residue‐mediated suppression of weed establishment in spring varied among the cover crop species, with winter oilseed rape offering relatively strong effects during both periods.     

山东省粮食作物的化肥施用状况分析

在农户抽样调查数据的基础上，分析了山东省粮食作物上施用化肥的状况。通过对山东省不同地区2003年施肥状况调查并结合统计资料分析表明，粮食作物上施肥占化肥总投入的比例逐年在下降，但单位面积化肥投入量却稳步提高。在氮肥的品种构成中，低浓度的碳酸氢铵提供了46．8％的施氮量，仍占有重要地位。山东省粮食作物单位面积化肥平均用量为251．1kg／hm^2，其中小麦平均施肥量最高，达到277．6kg／hm^2；另外就施氮量来说，玉米施氮量最高，平均用量为175．2kg／hm^2；小麦施磷量最高，平均用量为97．6kg／hm^2；薯类施钾量最高，平均用量为55．7kg／hm^2。从施肥的氮磷比例来看，小麦上施用化肥的氮磷比例为1：0．7，高于推荐施肥比例，玉米上施用化肥的氮磷比例为1：0．25，低于推荐施肥比例。     

海南岛各县与世界热带国家农业气候相似性研究

本文以海南岛气候资源、热作生产实际及农业气候相似性原理为依据,选取年均温及月均温的年内分配,年雨量及月雨量的年内分配共26个具有农业意义的气候因子,采用多元统计中的相似分析方法,通过上机运算,取得了海南岛各县与世界热带21个国家24个点站的农业气候相似系数,并按系数的大小进行了相似性等级区划;最后与实际数据进行印证对比,结果表明,各地的理论系数及其相似性等级划分与实际吻合,具有较好的指导意义。     

棉田种植诱集作物对天敌的保护及增殖作用

1987—1988年在河北省邯郸地区的试验结果表明,在棉田种植油菜及高粱诱集带,棉花主要害虫发生期内捕食性天敌数量比对照田增加25—51％;当棉田施用化学农药时,诱集带对保护天敌、促使捕食性天敌数量回升的效果明显。两种诱集作物综合种植的相互衔接,对保护、增殖天敌和控制害虫作用明显优于单一种植高粱诱集带。     

Agronomic Practices at Low Environmental Impact for Durum Wheat in Mediterranean Conditions

The application of conservative agricultural practices such as crop rotation, shallow tillage, and organic fertilizer could usefully sustain crop yield and increase soil fertility, thus playing an important role in the sustainable agriculture. This study was conducted to determine the effects of conservative agronomic practices on yield and quality of wheat. The effects of these practices on soil fertility were further investigated in this four-year study (2005–2008). Two cropping systems, durum wheat in continuous cropping, and in two-year rotation with leguminous crops, were investigated at Foggia (Southern Italy) in rain-fed conditions. Within each cropping system, two levels of crop management were compared: i) conventional, characterized by a higher soil tillage management and mineral fertilizers application; ii) conservative, with a lower soil tillage management and organic-mineral fertilizers. The seasonal weather greatly affected the wheat yield and quality, inducing lower production in years that were characterized by unfavorable climatic conditions. This trend was found when the conventional treatment was applied, both in continuous cropping and rotations. The effects of cropping systems and crop management pointed out the positive role played by the leguminous crops (common vetch and chickpea) in crop rotation. This introduction improved wheat yield in rotation (6.47% compared to the continuous cropping), improved grain protein content (5.88%), and reduced the productive gap between conventional and conservative treatments (9.24 and 14.14% of the wheat in rotation and continuous cropping, respectively). Conversely, the effects of cropping systems and crop management on soil fertility were not very high, since the differences found at the end of the study in total nitrogen values were poor. However, total organic carbon (16.04 and 17.58% for cropping system and crop management, respectively) and available phosphorus values (11.30 and 7.43%) depend on root organic matter contribution, plant biomass residues, and fertilizations. The suitable crop rotation and the sustainable crop management appear important agronomical practices to improve yield and quality of wheat, and may reduce the environmental risks resulting from conventional intensive cropping systems.     

不同肥料不同作物对铅污染土壤修复及酶活性的影响

通过盆栽试验,采用随机组合设计,研究施用菌肥和腐殖酸对铅污染土壤上玉米、高粱、蓖麻、向日葵对铅的吸收效果及其生长成熟后对土壤酶活性的影响。结果表明,在铅污染土壤上施用菌肥、腐殖酸,有效降低了重金属铅的毒害;能有效提高土壤中酶的含量,其中,过氧化氢酶含量提高11.9%⁵5.0%,磷酸酶含量提高1.2%55.0%,磷酸酶含量提高1.2%²6.0%,脲酶含量提高43.1%26.0%,脲酶含量提高43.1%⁸0.7%,蔗糖酶含量提高17.7%80.7%,蔗糖酶含量提高17.7%³6.7%;铅吸收量以重金属Pb与菌肥混合施用(Pb+J)处理玉米最为显著,达到214.67 mg/kg。说明施用菌肥和腐殖酸可以达到修复铅污染土壤的目的。     

红壤丘陵果农复合系统的小气候效应初步观察

果农复合系统是江西丘陵红壤开发的主要模式。试验表明,果农复合系统能增加空气湿度,调节温度,稳定土壤水热状况,对改善小气候具有一定的作用,从而为改善整个小流域的气候环境创造了条件,是一种值得推广的耕作模式。     

基于灰色关联分析法的东北地区主要粮食作物综合效益评价

为合理布局作物生产,利用东北地区71个站点的气象资料以及年鉴资料,运用灰色关联分析法对东北地区主要粮食作物的综合效益,按产量效益、经济效益和生态效益各项指标进行综合评价。结果表明:吉林省南部和中部平原及辽宁省大部地区最适宜种植玉米;黑龙江省大部地区及辽宁省东南部地区最适宜种植水稻;而大豆适宜种植在东北北部、东部低温或多雨地区。     

河北省薯类资源开发与综合利用的探讨

通过推广高干型薯类优良品种和高产栽培技术;开展好薯类的就地加工,把薯类粉丝生产搞上去;发展薯类的深度加工和综合利用;改进落后的技术装备;发展适销对路的薯类食品工业;建立统一管理的协调组织;加强科学研究,推广科技成果等措施、对我省的薯类资源开发与综合利用,提高其经济效益具有现实意义。