Productivity and Sustainability of Cotton (Gossypium hirsutum L.)–Wheat (Triticum aestivum L.) Cropping System as Influenced by Prilled Urea, Farmyard Manure and Azotobacter

Field experiments were conducted at Indian Agricultural Research Institute, New Delhi, during 2001–2002 and 2002–2003, to study the effect of inorganic, organic and Azotobacter combined sources of N on cotton (Gossypium hirsutum L.) and their residual effect on succeeding wheat (Triticum aestivum L.) crop. The results indicated considerable increase in yield attributes and mean seed cotton yield (2.33 Mg ha^?1) with the combined application of 30 kg N and farmyard manure (FYM) at 12 Mg ha^?1 along with Azotobacter (M₄). The treatment in cotton that included FYM, especially when fertilizer N was also applied could either improve or maintain the soil fertility status in terms of available N, P and K. Distinct increase in yield attributes and grain yield of wheat was observed with the residual effect of integrated application of 30 kg N ha^?1 + FYM at 12 Mg ha^?1 + Azotobacter. Direct application of 120 kg N ha^?1 resulted 67.4 and 17.7 % increase in mean grain yield of wheat over no N and 60 kg N ha^?1, respectively. Integrated application of organic and inorganic fertilizer is therefore, recommended for higher productivity and sustainability of the cotton–wheat system.     

Soil steaming to reduce intrarow weed seedling emergence

Steaming the soil prior to crop establishment can be a very effective method of preventing weed seedling emergence on raised beds of vegetable crops. However, current mobile steaming technology for outdoor vegetables is characterized by an extremely high energy consumption and a low work rate. This has led to the concept of band-steaming, where only a limited soil volume is steamed corresponding to the intrarow area of a row-grown vegetable crop. Weeds growing in the intrarow area are difficult to remove by traditional non-chemical means, usually involving substantial input of manual labour in organic cropping. This paper presents the initial results from laboratory studies with steaming a limited soil volume simulating a band. The investigations describe the relationship between maximum soil temperature achieved from soil steaming for different periods and effects seen on subsequent weed seedling emergence. The relationships obtained were generally sigmoid and could appropriately be described by a common dose–response function. Seedling emergence from natural weed species was reduced by 90% when the maximum soil temperature reached 61°C, and a further 10°C rise in temperature gave 99% reduction. Added and non-imbibed seeds of Lolium perenne and Brassica napus generally required higher temperatures to achieve the same control level as the natural weeds in the soil samples.     

再生稻高产栽培综合农艺措施研究

用二次回归正交旋转组合设计，研究了再生稻综合农艺措施对产量的影响，建立了相应数学模型，得出了最佳逐艺措施组合方案。即在重庆地区，再生稻用促芽氮肥１４５．１６－１５７．５２ｋｇ／ｈａ，于头季稻齐穗后２２－２４天施，头季稻齐穗后１５天配施磷钾９９．９５－１０８．１１ｋｇ／ｈａ，留桩高度２４－２８ｃｍ，发苗肥４８．３４－５７．５８ｋｇ／ｈａ，再生和妥产量可达１８９０ｋｇ／ｈａ以上。     

试论黑麦草生产在我国农业三元种植结构调整中的地位和作用

三元种植结构取代二元种植结构是我国现代化农业发展的必然趋势。多花黑麦草作为一种优质、高产的禾本科首选作物 ,在 5个方面的作用将对我国农业全局产生重大而深远的影响     

稻/草-鹅农牧结合模式的综合效益及种养技术初探

1997－1999年在江苏省常熟市构建稻／牧草－鹅复合系统，并进行田间试验，结果表明，稻／草－鹅农牧结合模式与传统的稻／麦生产模式相比，不但具有明显的社会效益，经济效益，而且能显著提高土壤肥力，有效控制冬季田间杂草，进而大幅度降低田间除草剂，杀虫剂施用量，保护农田生态环境，总结了该模式的种养式技术，并提出了该模式的发展策略。     

长期轮作连作对不同作物土壤磷组分的影响

对长期轮作连作条件下的大豆、玉米、小麦土壤磷组分进行研究,试验结果表明,供试土壤在不施肥情况下,土壤全磷以轮作区降幅最大,而土壤有效磷以小麦连作区降幅最大,土壤磷组分以大豆连作区土壤中的Ca2-P降幅最大;在施有机肥的情况下,土壤全磷以大豆连作区增幅最大,而土壤有效磷以轮作区增幅最小,土壤磷组分以轮作土壤中的Ca2-P增幅最大。     

大豆专用肥对轮作,连作大豆叶片超微结构的影响

本文通过透射电镜观察了常规施肥与施用大豆专用复肥对轮作。连作大豆叶片超微结构的影响。结果发现，大豆连作导致叶绿体基粒片层结构破坏，淀粉粒积累，基粒片层结构出现“空隙区”。与常规施肥相比，施用复肥增强了轮作，连作大豆叶片叶绿体基粒片层结构的完整性，增加了基粒数量和基粒片层数，为促进大豆叶片的光合作用创造了条件，相关分析表明，叶绿体基粒片层数与大豆植株营养生长呈显著正相关。     

微生物肥对连作障碍土壤上芥蓝生长的影响

为解决土壤连作障碍问题,以不施微生物肥作对照,选用沃益多、德根贝2种微生物肥在芥蓝上进行设施栽培肥效对比试验。试验结果表明,施用微生物肥后芥蓝产量和经济效益均较对照有所增加,其中,沃益多处理的芥蓝产量增幅为10.07%,增值22 163元/hm2,德根贝处理的产量增幅为11.46%,增值25 817元/hm2,且达到显著差异,说明微生物肥对连作障碍有很好的缓解作用。     

Genetic variation in bitter pit and fruit calcium concentrations within a diverse apple germplasm collection

Summary Genetic variability in the apple [Malus] fruit disorder bitter pit and fruit calcium concentrations ([Ca]) was determined in 25 seedling families at each of two sites from 1999 to 2000 and again for one site, in 2001. Most trees were free of pit or had low pit incidence, which could be approximated by an over-dispersed binomial distribution. A genetic component to external and internal pit incidence was found across both sites and all years. This effect was irrespective of the use of several cropping factors, average fruit weight or fruit mineral concentrations as covariates in the analyses. Year and/or site always had substantial effects on pit incidence. Interactions of genetic effects with site or year were also detected with large differences in mean pit incidence between sites or years for some families but not others. No relationship was found between mean family pit incidence and mean family [Ca] or mean family harvest date. However fruit [Ca] and harvest date were usually important predictors of within-family variation in pit incidence. For any one seedling, family had the largest effect on bitter pit incidence followed by site and [Ca] and the smallest effect was that of harvest date. [Ca] showed a strong genetic component and estimated family means of [Ca] were consistent at different sites and years. These results suggest that susceptibility of apple genotypes to bitter pit in breeding programmes may be best assessed through screening across multiple sites and seasons. Fruit [Ca] might be useful as an indirect selection index for bitter pit within, but not among families.     

营养液条件下油酸对黄瓜幼苗生长的影响

水培条件下，研究不同油酸水平对黄瓜幼苗生长的直接影响。与对照相比，生物量和生理指标等表明，油酸10μL/L水平对黄瓜生长几乎没有负面影响，而油酸水平为100，500，1000μL/L则表现出一定的抑制效应。其中，1000μL/L水平中黄瓜的生长明显受到抑制。试验还表明，油酸对黄瓜幼苗没有表现出直接的生长刺激效应。