有机水稻品种产量、品质和氮素吸收利用的关系

Due to the relatively late start of organic rice (Oryza sativa L.) research in China, there is a still lack of systematic research on rice varieties, organic fertilizer management practices, and especially the mechanisms of nitrogen (N) uptake and utilization. Three rice varieties, Nanjing 5055, Nanjing 9108, and Nanjing 46, were grown at organic farming (OF) with three organic fertilizer levels (103.2, 160.8, and 218.4 kg N ha^-1) and conventional farming (CF) with regular chemical fertilizers. Rice grain yields, yield components, and quality, dry matter accumulation, and plant N were measured at different growth stages during the 2012 and 2013 growing seasons. Compared with CF, OF had a significantly reduced yield. Nanjing 9108 showed significant reductions in number of panicles per unit area and the percentage of filled grains, and had the lowest yield. The effects of fertilizer type and application rate on dry matter accumulation during the main growth periods were significant for all varieties. The N content and uptake of organically grown rice were lower compared with that of rice under CF. The N recovery efficiency and N agronomic efficiency were significantly lower, whereas N physiological efficiency and N partial factor productivity were greater under OF than under CF. Under OF, the processing quality showed a slight but insignificant decline, protein content and gel consistency increased, and amylose content decreased compared with those under CF. Correlation analysis showed that under OF, grain yield was significantly correlated with N uptake. The medium organic fertilizer level (160.8 kg N ha^-1) was found to be the optimum fertilizer treatment, and Nanjing 46 appeared to be the best variety for organic rice cultivation. To increase rice grain yields and reduce the potential risk of non-point source pollution in organic agriculture, further research is needed to improve the N use efficiency in organic rice cultivation.     

稻米真空保鲜储藏技术研究

通过稻米常规储藏和真空储藏的对比试验,研究了稻米真空保鲜储藏原理和品质劣化机理。在真空储藏和常规条件下,稻米的食味都下降,但在真空条件下,稻米中的脂肪酸、含水率和淀粉的理化性质变化幅度比常规条件下的小,因此真空储藏比常规储藏更好保持稻米的食味。研究发现稻米的含水率越高,储藏期间食味变化率越大。真空储藏能够减少黄粒米产生,抑制霉菌、害虫生长。研究得出了各种含水率稻米的合理真空储藏参数,经生产性试验验证可行。     

有机种植与常规种植体系的比较——基于土壤与肥料的视角

有机种植体系因其安全、绿色、可持续的特点在国内外得到了普遍关注,自其发展以来,关于有机与常规种植体系的比较屡见不鲜,但基于土壤与肥料视角的系统比较在国内还鲜见报道。土壤为植物提供了直接生活环境,从土壤与肥料的角度能全面地理解有机与常规种植体系的本质不同及影响。本文综合分析了前人的研究结果,从土壤与肥料的视角对有机和常规种植体系进行系统比较,初步阐述了两种种植体系下作物产量、品质、土壤肥力效应、环境效应的差异及产生差异的可能原因。分析发现在作物种植初期有机体系的产量大多低于常规体系,但增产潜力较大;相比常规种植体系,有机种植体系可改善土壤性质、提高土壤肥力,且一般有助于提高农产品品质;此外,有机种植体系对大气环境和水环境的污染风险低于常规种植体系。产生差异的原因可能是有机种植体系下,前期土壤氮素及速效养分释放较缓慢,且随着种植年限的增加,土壤固碳能力逐渐增强,土壤微生物多样性增加,土壤养分利用率提高。     

Impact of long-term organic and inorganic nutrient managements on the biological properties and eubacterial community diversity of the Indian semi-arid Alfisol

Intensive cropping with limited nutrient management options in low fertile semi-arid tropical soils will have agricultural sustainability problems in future. A better understanding of soil variables as influenced by long-term nutrient amendments could lead to the identification of more precise indicators to monitor soil fertility that would promote sustainability. Long-term nutrient experiment in semi-arid Alfisol at Coimbatore, India was investigated in two successive years, 2009 and 2010 to assess the enduring effects of organic (OM) and inorganic (IC) nutrient managements on soil variables. The organic amendments induced higher microbial population and enzyme activity compared to IC and control soils. The principal component analysis of observed variables revealed that soil organic carbon, microbial biomass carbon (MBC), dehydrogenase and alkaline phosphatase activity and diazotrophs population could be the possible indicators for predicting soil fertility resulting from long-term nutrient managements. The eubacterial community profile assessed by 16S rRNA gene sequence polymorphism revealed that the abundance and relative ratio of phyla belonging to Proteobacteria, Actinobacteria, Acidobacteria and Firmicutes were considerably affected due to either organic manures or inorganic fertilizers, and organic nutrient management favours bacterial community diversity. These results emphasize the importance of organic nutrient management to maintain soil biological properties in semi-arid Alfisol.     

Arbuscular mycorrhizae in a long-term field trial comparing low-input (organic, biological) and high-input (conventional) farming systems in a crop rotation

 Arbuscular mycorrhizal (AM) root colonization was studied in a long-term field trial in which four farming systems currently in use in Switzerland were continuously applied to a randomized set of plots at a single field site from 1978 till 1993. There were two low-input farming systems (organic and bio-dynamic) and two high-input (conventional) farming systems (according to Swiss guidelines of integrated plant production with and without farmyard manure). The systems had an identical 7-year crop rotation and tillage scheme and differed essentially only in the amount and type of fertilizer supplied and in plant protection management. The percentage of root colonization by AM fungi was determined in field samples 2–3 times over the growing season in crops in the rotation, namely in winter wheat (Triticum aestivum L. cv. Sardona), vetch-rye and grass-clover. We found the percentage of root length colonized by AM fungi to be 30–60% higher (P≤0.05) in the plants grown in soils from the low-input farming systems than in those grown in conventionally farmed soils. Approximately 50% of the variation of AM root colonization was explained by chemical properties of the soils (pH, soluble P and K, exchangeable Mg), the effect of soluble soil P being most pronounced. The potential of the field soils from the differently managed plots to cause symbiosis with AM fungi was tested in a glasshouse experiment, using wheat as a host plant. Soils from the low-input farming systems had a greatly enhanced capacity to initiate AM symbiosis. The relative differences in this capacity remained similar when propagules of the AM fungus Glomus mosseae were experimentally added to the soils, although overall root colonization by AM fungi was 2.8 times higher. Received: 27 August 1999     

天水旱作区玉米品种比较试验初报

玉米是天水市的主要粮食作物之一。为了筛选适宜在天水旱作区种植的优良玉米品种,2021年对从当地收集的27个玉米品种进行比较试验。结果表明,27个参试玉米品种在当地气候条件下均能正常成熟。以优迪919折合产量最高,为13 014.29 kg/hm2,较对照品种先玉335增产11.08%;玉源7879次之,折合产量为12 995.24 kg/hm2,较对照品种先玉335增产10.92%;翔玉218居第3位,折合产量为12 941.27 kg/hm2,较对照品种先玉335增产10.46%;登海182、德单1403、龙博士7号、翔玉329、登海9号、金凯3号折合产量也较高,分别较对照品种先玉335增产9.31%、9.05%、8.56%、8.16%、8.12%、7.56%。这9个品种较对照品种先玉335增产幅度均在7.50%以上,且农艺性状、经济性状优良,总体表现相对较好,可在天水市旱作农业区种植。     

香港有机农业发展

有机农业是利用天然再生资源配合环境和生态作用以生产高质量农产品和避免虫害的可持续农业生产方式。在20世纪80年代,有机农业由一些环保团体引入香港;在过去10年间,有机农业广泛引起社会的注意和兴趣。2000年香港政府推出（有机耕作转型计划）,目的主要是为香港农业创造新的生产模式,同时为市民提供多一个新鲜农产品的选择机会。首先介绍有机农业的一些重要概念和香港有机农业的发展过程,然后分析并评论有机耕作转型计划的成功和失败之处。