中国三大自然区域紫花苜蓿土壤速效钾丰缺指标和推荐施钾量

为给内蒙古高原区、黄土高原区和西北荒漠绿洲区紫花苜蓿测土施肥奠定科学基础,采用零散实验数据整合法以及养分平衡-地力差减法,开展了三大自然区域紫花苜蓿土壤速效钾丰缺指标和推荐施钾量研究。结果表明,内蒙古高原区紫花苜蓿土壤速效钾第1~4级指标依次为≥342mg/kg、89~342mg/kg、24~89mg/kg和<24mg/kg,黄土高原区第1~6级指标依次为≥171mg/kg、96~171mg/kg、54~96mg/kg、30~54mg/kg、17~30mg/kg和<17mg/kg,西北荒漠绿洲区第1~4级指标依次为≥303mg/kg、140~303mg/kg、65~140mg/kg和<65mg/kg;当目标产量9~27t/hm²、钾肥利用率50%时,第1~6级土壤的推荐施钾量分别为0、54~162kg/hm²、108~324kg/hm²、162~486kg/hm²、216~648kg/hm²和270~810kg/hm²。     

AM真菌改善植物磷营养吸收和转运机制的研究进展

旨在深入了解丛枝菌根(Arbuscular mycorrhizae,AM)真菌在植物吸收和转运磷元素方面的机制。本研究归纳了近年来关于AM真菌能够促使植物改善磷营养（如磷酸盐转运蛋白、磷酸酶基因等）相关的最新研究成果,着重分析了AM真菌的菌根吸收途径,总结了国内外关于AM真菌对水溶性无机磷、难溶性无机磷和有机磷等3种土壤磷存在形态下的利用机制。最后指出该领域仍存在的一些问题以及未来的研究侧重点。     

Measuring fish catch and consumption: Practical methods for small‐scale fisheries based on length as an alternative to weight‐based approaches

Small‐scale fisheries are recognised as making important contributions to nutrition and economic development despite a lack of accurate quantitative information on catches and consumption. While direct measurement remains the most appropriate way of collecting such data, it is impractical at large scales. Instead, household surveys based upon informant recall of fish caught and/or consumed are frequently used. However, the accuracy of weight recall by informants (even over short recall periods) has not been established. Using data from household surveys, the accuracy and precision of catch and consumption estimates derived from: (a) asking informants to recall weights of fish caught and (b) asking respondents to recall lengths of fish caught and converting to weight were tested. Length‐based methods, using visual aids to assist recall, were more accurate, precise and correctable. These methods could be useful for catch estimation, especially where fish are processed, sold or consumed shortly after capture.     

疏花对无核荔枝果实和树体营养的影响

为了研究疏花对无核荔枝果实和树体营养的影响,以不疏花为对照,在初花期对其进行疏花处理,统计疏花量、记录果实发育情况及成熟日期,并测定果实成熟时的品质和整个过程中树体叶片营养变化情况。据统计,每株树的平均疏花量达到80%-90%左右,疏掉的小穗数、支穗数和侧穗数分别为89.81%、89.74%、81.82%。试验结果表明,疏花使无核荔枝的果实发育情况及果实成熟时的可食率、单果重、总糖、维生素C、还原糖均高于对照；果实成熟时,平均单株产量提高70.59%；疏花处理的果实成熟期较对照提前7天左右；该过程中树体叶片N、P、K、S、Ca、Mg含量在前期高于而后期稍低于对照。疏花加快了无核荔枝果实生长发育,并提高了果实的产量和品质。     

Comparison of yield,fruit quality,antioxidant activity,and some phenolic compounds of white seedless grape obtained from organic,conventional, and integrated fertilization

The aim of this research was to determine the effect of three different fertilizing systems, including organic, conventional, and integrated ones, on the yield, fruit quality, antioxidant activity, and some phenolic compounds of white seedless grape. The study was carried out on several 6-year-old white seedless grapevine located in the Urmia Province (North-West Iran). The results showed that the fruit physical characteristics and yield were affected significantly by different fertilization systems. The highest yield was observed in the conventional fertilization, followed by organic and integrated systems. The leaf mineral contents were obviously dependent on the different fertilization used, whereas pH and titratable acidity were not affected. Based on our results, the highest values of antioxidant activity and total flavonoid were found in the organic and integrated fertilization systems, respectively. Also, the highest contents of total phenolic, catechin, and quercetin-3-galactoside were observed in the organic fertilization system. Overall, the highest nutritional quality and biochemical characteristics of white seedless grape were obtained in organic fertilization system, which improved antioxidant capacity by enhancing total phenolics, total flavonoids and valuable phenolic compounds.     

包膜含缩节胺氯化钾对棉花产量及土壤钾素的影响

棉花是具无限生长特性的喜钾作物，为解决其生育期内多次追施钾肥和叶面喷施缩节胺的用工问题，实现轻简化种植目标，研究包膜含缩节胺氯化钾对棉花产量、经济效益和土壤钾素变化特征的影响。试验设5个处理，分别为一次基施180 kg?hm-2包膜含缩节胺氯化钾（CRKMC）、减少30%钾素用量（126 kg?hm-2）的包膜含缩节胺氯化钾（70%CRKMC）、基施180 kg·hm^-2普通包膜氯化钾（CRK）、分次施用180 kg?hm-2普通氯化钾（KCl）和对照（CK，不施钾肥），后三个处理叶面喷施三次缩节胺。结果表明：等量施钾条件下，CRKMC和CRK较KCl籽棉产量分别增加8.81%和9.36%，经济效益分别增加15.53%和12.86%，70%CRKMC较KCl增产6.53%，增加净收入13.64%。CRKMC抑制棉花盛花期前的株高，提高后期株高、茎粗和叶绿素含量，使生物量较KCl增加18.56%~24.98%，提高钾素吸收量，表观利用率增加25.06~38.83个百分点。CRKMC中的钾素和缩节胺在土壤中呈“先慢后快而后趋于平缓”的规律，释放高峰出现在盛花期至始絮期，显著提高蕾期以后土壤中的速效钾含量。因此，土壤基施包膜含缩节胺氯化钾，可合理协调棉花生长势指标，满足钾素吸收需求，减少30%用量仍有较高的经济效益和钾素利用率，实现了缩节胺和钾素在同一时空条件下的一体化调控，有助于棉花减肥、高产和轻简化种植。     

Introduction to the International Symposium on Lipid Science and Health and research progress in lipid science and health

The International Symposium on Lipid Science and Health (ISLSH), which was organized annually by Oil Crops Research Institute of Chinese Academy of Agricultural Sciences (OCRI-CAAS) since 2016, has gained a strong reputation and attracted hundreds of delegates from around the world for discussion of lipid research trends and advances every year, to promote research and academic exchanges in the fields of lipid science and health. The 5th International Symposium on lipid Science and Health was successfully held in Wuhan, China, from October 23rd to 25th, 2020, to celebrate the 60th anniversary of OCRI-CAAS. The two-day symposium gathered well-known experts specialized in lipid science to share the current state of lipid research with emphasis on aspects covering: (1) lipid profiling and characterization, (2) lipid preparation and modification, (3) lipid improvement and regulation, and (4) lipid nutrition and health. The symposium was conducted by a combination of on-site and network meeting. More than 250 distinguished delegates from academia and industry participated in the on-site multidisciplinary meeting, and thousands of scholars attended the virtual event. This paper is as a record of the symposium proceedings and a brief summary of the advances and trends in 4 aspects of lipid science and health.     

Phytolith‐associated potassium in fern: characterization,dissolution properties and implications for slash‐and‐burn agriculture

In recent time, phytoliths (silicon deposition between plant cells) have been recognized as an important nutrient source for crops. The work presented here aims at highlighting the potential of phytolith‐occluded K pool in ferns. Dicranopteris linearis (D. linearis ) is a common fern in the humid subtropical and tropical regions. Burning of the fern D. linearis is, in slash‐and‐burn regions, a common practice to prepare the soil before planting. We characterised the phytolith‐rich ash derived from the fern D. linearis and phytolith‐associated potassium (K) (phytK), using X‐ray tomographic microscopy in combination with kinetic batch experiments. D. linearis contains up to 3.9 g K/kg d.wt, including K subcompartmented in phytoliths. X‐ray tomographic microscopy visualized an interembedding structure between organic matter and silica, particularly in leaves. Corelease of K and Si observed in the batch experiments confirmed that the dissolution of ash phytoliths is one of major factors controlling K release. Under heat treatment, a part of the K is made available, while the remainder entrapped into phytoliths (ca. 2.0–3.3%) is unavailable until the phytoliths are dissolved. By enhanced removal of organic phases, or forming more stable silica phases, heat treatment changes dissolution properties of the phytoliths, affecting K release for crops and soils. The maximum releases of soluble K and Si were observed for the phytoliths treated at 500–800 °C. For quantitative approaches for the K provision of plants from the soil phytK pool in soils, factors regulating phytolith dissolution rate have to be considered.     

Effect of dietary protein content on growth rate,survival and body composition of juvenile cauque river prawn,Macrobrachium americanum (Bate 1868)

We determined the effect of four concentrations of dietary crude protein, 30.7, 37.2, 41.8 and 46.8% on growth rate, survival and body composition of the juvenile cauque river prawn (Macrobrachium americanum). The prawns were hatched in the laboratory from the spawn of one wild ovigerous female. Prawns consuming 37.2% crude protein reached a final weight of 0.58 g (feed conversion ratio of 2.15), which was significantly better than the other treatments. Survival was 100% in all treatments. Protein content in the diets had no significant effect on whole body proximate composition and amino acid profile. Juveniles consuming the 37.2% crude protein diet grew faster than those fed the other diets. Specific growth rate was adjusted to the two‐slope broken‐line regression analysis model to estimate the optimal protein requirement. In conclusion, these results demonstrated that the 37.2% protein level diet is optimal for juvenile cauque river prawn M. americanum in the experimental conditions of this study.     

基于RGB颜色空间的早稻氮素营养监测研究

针对双季稻区水稻过量施肥带来环境污染和成本提高问题,设计不同品种氮肥梯度大田试验,应用数码相机获取早稻冠层数字图像,研究不同色彩参数及早稻氮素营养指标的时空变化特征,以期确立双季早稻氮素营养预测模型。结果表明:不同品种同一氮肥处理下图像色彩参数差异不大;拔节期数字图像参数对氮素营养指标敏感;模型构建结果显示,图像参数INT与水稻氮素营养指标构建的模型决定系数(R2)最大,模型预测效果最佳,R2分别为0.895 7和0.924 7;进一步采用多元回归分析和BP神经网络分析法进行预测,预测效果均较好。对预测结果进行检验,发现品种对于模型的构建影响不大,以BP神经网络分析法构建的叶片氮浓度(LNC)模型和以INT为敏感色彩参数构建的叶片氮积累量(LNA)回归模型效果最优,而多元回归分析方法则效果不佳。早稻冠层RGB颜色空间敏感参数与氮素营养指标间相关性较好,可以实现氮素营养的无损监测诊断。