Response of Over-summer Hydroponic Lettuce to Nutrient Solution Temperature Control

Temperature, as an important feature of hydroponic nutrient solution, is closely related to dissolved oxygen content of nutrient solution and growth status of plant roots. How to precisely adjust the temperature of nutrient solution is the key to obtain high quality and high yield of hydroponic vegetables over summer. With Lactuca sativa vat. crispa ＇Luosheng No.3＇ as the test material, the effect of chiller cooling technology on the temperature of nutrient solution, as well as on the yield and quality of Luosheng No.3, in over-summer hydroponic cultivation was studied. The results showed that the chiller cooling technology controlled the nutrient solution temperature in a reasonable range （（20 ± 1）℃） and promoted the growth and dry matter accumulation of Luosheng No.3, instead of affecting the quality. In short, the chiller cooling technology is applicable to the temperature regulation of nutrient solu- tion in hydroponics over summer.

Nutrient patterns and risk of cataract：a case-control study

AIM：To assess the relation between nutrient patterns and cataract risk.METHODS：This is a hospital-based case-control study with 97 cataract patients and 198 matched controls.Dietary consumption was collected through a valid food frequency questionnaire（FFQ）.Nutrient patterns were detected by applying factor analysis.Unconditional logistic regression models were used to estimate odds ratio（ORs） and 95%CIs.RESULTS：We extracted 5 main nutrient patterns.Factor 1 included niacin,thiamin,carbohydrates,protein,zinc,vitamin B6 and sodium（sodium pattern）.Factor 2 was characterized by oleic acid,monounsaturated fats,polyunsaturated fats,linoleic acid,trans fatty acid,linolenic acid,vitamin E and saturated fats（fatty acid pattern）.The third factor represented high intake of vitamin B12,vitamin D,cholesterol and calcium（mixed pattern）.The 4^（th） pattern was high in intake of beta and alpha carotene,vitamin A and vitamin C（antioxidant pattern）.Finally,the 5^（th） pattern loaded heavily on docosahexaenoic acid（DHA） and eicosapentaenoic acid（EPA）（omega-3 pattern）.In crude and multivariate analysis,the sodium pattern was associated with increased risk of cataract（OR=1.97,95%CI：1.09-3.96）.The fatty acid pattern elevated the risk of cataract（OR=1.94,95%CI：1.1-3.86）.Antioxidant pattern was associated with a significant 79% reduced risk（2^（nd） category compared with the 1st）.Omega-3 pattern was significantly negatively associated with risk of cataract（P=0.04）.CONCLUSION：These findings imply that nutrient patterns reflecting a combined consumption of nutrients might be important in the etiology of cataract.Additional studies with more efficient designs are warranted to confirm our findings.

Identification of Quantitative Trait Loci Controlling Seed Physical and Nutrient Traits in Cotton

Cotton(Gossypium spp.) is the leading fiber crop,and an important source of the important edible oil and protein meals in the world.Complex genetics and strong environmental effects hinder

Hydrological Controls on Nutrient Exportation from Old-Growth Evergreen Rainforests and <i>Eucalyptus nitens</i>Plantation in Headwater Catchments at Southern Chile

Soil cover disturbances have a direct effect on biogeochemistry, potentially enhancing nutrient loss, land degradation and associated changes in ecosystem services and livelihood support. The objective of this study was to assess how canopy affected throughfall chemistry and how hydrology affected stream nutrient load responses in two watersheds dominated by native old-growth evergreen rainforest (NF) and exotic plantation of Eucalyptus nitens (EP), located at the Coastal mountain range of southern Chile (40&deg;S). We measured nitrogen (NO3-N, NH4-N, Organic-N, Total-N) and total phosphorus (Total-P) at catchment discharge, and δ18O in throughfall precipitation and stream discharge in both catchments, in order to separate throughfall (or new water) contributions during storm events. It was hypothesized that all nutrients showed an increase in concentration as discharge increased (or enhanced hydrological access), in EP;but not in NF. Our results indicated that Organic-N, Total-N and Total-P concentrations were positively related to discharge. However, NO3<sup style="margin-left:-7px;">--N showed a negative correlation with catchment discharge. Organic-N and Total-P showed a flush during storm events;the opposite was observed for NO3<sup style="margin-left:-7px;">--N. However, this behavior suggested that NO3<sup style="margin-left:-7px;">--N was being retained by charged particles or soil micro biota, whether Organic-N was flushed as it was more concentrated in big pore water that was not tightly attached, compared with NO3<sup style="margin-left:-7px;">--N.

An Electro-Mechanical Controller for Adjusting Piston Pump Stroke On-the-Go for Site-Specific Application of Crop Nutrients

Nutrient application systems are designed to apply a relatively uniform amount of a fertilizer to agricultural fields. However, considerable variation in soil texture and other characteristics often occurs within and across production fields, which could have a major impact on fertilizer management strategies. Therefore, uniform application of a fertilizer over the entire field can be both costly and environmentally unsound. Due to their rugged and fool-proof design, crankshaft type piston pumps are widely used in agriculture. The on-the-go outlet flow of these pumps can only be varied by changing the drive shaft speed for each pump stroke setting. But only a limited range of flow rates can be achieved by changing the drive shaft speed. There is a need for an electronic controller, which can adjust the pump stroke on-the-go, for real-time, variable-rate application of crop nutrients. The Clemson “Electro-me-chanical controller for adjusting pump stroke on-the-go” was designed to replace the current manual stroke adjustment system on positive displacement piston pumps. This affordable system can be retrofitted on most John Blue - piston pumps for real-time adjustment of the pump stroke and can be controlled using pre-described position sequences (map-based) or real-time sensor commands (such as optical, pressure, and flow sensors) combined with fertilizer calculation algorithms. In addition, it can adjust pump stroke manually, using an eclectic dial from the tractor’s cab.

棉隆土壤消毒联合种植密度防除油菜田杂草及对作物产量和田间光照的影响

在农田杂草的治理中,结合农艺措施来治理草害的发生,可有效减少化学除草剂的使用,实现草害的综合治理。本文采用田间试验研究了棉隆土壤消毒联合油菜不同种植密度对油菜田主要杂草野燕麦Avena fatua、苦苣菜Sonchus oleraceus的防除效果,及杂草对氮、磷、钾及水分消耗的影响。结果表明,土壤消毒联合种植密度对油菜田杂草防除效果显著,对野燕麦、苦苣菜均有良好防效,总鲜重防效达到89.8%~100.0%。采取防除措施后,杂草对田间氮、磷、钾和水分的消耗量减少85%以上,有效改善了田间的水肥和光照条件。土壤消毒联合种植密度不同处理的油菜籽产量达到3155.0~4920.5 kg/hm^(2),增产效果显著,产量较未消毒土壤区增加13.3%~76.8%,增收1857.3~10684.8元/hm^(2)。研究表明采用土壤消毒结合种植密度对油菜田杂草具有很好的控制效果,适度增加油菜种植密度既能保证对杂草防效,同时也能保证产量。

秸秆还田及不同比例控失尿素对华北平原小麦产量及潮土性质影响

为探讨不同控失尿素比例和秸秆还田对华北平原小麦产量及潮土化学性质的影响,本研究以华北潮土区小麦-玉米轮作体系为研究对象,采用裂区试验设计,以秸秆还田为主区,控失尿素比例为副区。秸秆还田模式设秸秆全量还田(S1)、秸秆不还田(S0)2种;控失尿素比例设不施肥(CK)以及控失尿素占总施氮量比例为0、40%、70%和100%(LCU0、LCU40、LCU70、LCU100)5个处理。在作物收割后进行产量测定,并采集0~20 cm耕层土壤进行常规土壤养分含量测定。结果表明:与S0处理相比,S1处理显著提高土壤有机质和速效钾含量。控失尿素显著提高土壤硝态氮含量,其他土壤养分含量无显著变化。秸秆不还田条件下,施用化肥显著降低了土壤pH值。控失尿素比例为70%时土壤养分含量最高。秸秆还田对小麦产量及吸氮量无显著影响,控失尿素对小麦产量及吸氮量增加具有极显著影响。在所有处理中,S1-LCU40处理的籽粒和秸秆产量最高,籽粒产量达7009.26 kg·hm^(-2),秸秆产量达11361.38 kg·hm^(-2)。秸秆还田对土壤氮素依存率具有显著影响,不同比例控失尿素对氮素收获指数具有显著影响,对氮肥表观利用率、土壤氮素依存率具有极显著影响。控失尿素比例为40%或70%时氮素吸收利用指标较优。综上,在华北平原潮土区,秸秆还田与40%控失尿素比例配施可以显著提升土壤供氮能力,提高小麦产量和氮素吸收与利用指标,是较为适宜的管理措施,但其机理及长期效应还需进一步研究。

控释尿素与普通尿素配施对橡胶树叶片和胶乳养分及产量的影响

为了明确控释尿素与普通尿素配施在橡胶树上的应用效果,通过2年田间试验,研究了减氮条件下控释尿素与普通尿素不同比例配施对橡胶树产量、叶片和胶乳矿质养分及土壤氮含量的影响,为橡胶树栽培管理中合理施氮提供技术支撑。结果表明:控释尿素与普通尿素配施可提高橡胶树干胶产量和叶片氮含量,与常规施肥相比,橡胶树干胶产量增幅为16.28%~39.13%(2021年)和7.94%~9.69%(2022年),叶片氮含量增幅为10.54%~19.17%(2021年)和10.24%~21.50%(2022年),控释尿素与普通尿素配施处理叶片氮含量均处于正常值以上。控释尿素与普通尿素配施还能够增加胶园肥穴土壤碱解氮含量,较常规施肥增加了11.27%~80.36%。控释尿素与普通尿素配施比例为50∶50时,橡胶树干胶产量(2022年)、叶片氮含量(2021—2022年)和土壤碱解氮含量(2021—2022年)均显著高于常规施肥。综上所述,在本试验条件下,控释尿素与普通尿素配施比例为50∶50能够获得较高的干胶产量,可改善叶片营养状况,维持土壤氮水平,有利于实现橡胶树施肥管理的绿色协同增效。

消减大豆连作障碍的养分调控技术研究进展

为明确不同养分调控技术对大豆连作障碍消减的作用,本文阐述了大豆连作障碍的发生与危害。从提高肥料养分供应能力、改善土壤理化性状和优化土壤微生物环境3个方面分别综述了针对大豆连作障碍中不同危害的解决方案。通过改变施肥方式、时间、数量等方式解决大豆长期连作导致土壤中养分偏耗和影响大豆生长发育的问题;通过使用不同改良剂针对性地解决土壤酸化、板结、保水保肥能力下降的问题;在大豆连作土壤中接入有益微生物,从而降低有害微生物及病原菌的活性,最终达到改善土壤微生物环境的效果。最后总结得出,消减大豆连作障碍过程中尚待解决的问题以及养分调控技术的研究方向,为大豆连作障碍的发生发展机理的研究、养分调控技术的优化改良提出建议和展望。

嘉兴海域主要污染物环境容量及总量控制研究

嘉兴海域近年来海洋生态环境质量明显退化,实施污染物总量控制作为保证海域环境质量的根本措施之一,有助于嘉兴海域污染物的减排与治理工作,保障嘉兴海域可持续发展能力。基于嘉兴临近海域水动力-水质模型与现场监测结果,依据浙江省近岸海域环境功能区划的水质要求,采用响应系数法与线性规划方法,计算了该海域重要排放口的化学需氧量COD、无机氮与磷酸盐环境容量,并针对削减扩容影响的总量控制措施进行计算与评估。结果表明,研究海域COD总环境容量为2.97×10^(5)t/a,仍有较大富余,而无机氮与活性磷酸盐含量均超四类海水水质标准,超过海域无机氮与磷酸盐环境容量。对现有规划进行合理的量化数值模拟,削减措施尽管减少了一部分扩容引起的COD、无机氮与磷酸盐含量的增加,使其保持平稳,但仍需继续优化污水处理能力,减少氮磷营养盐的排放。研究结果可为沿海城市陆源污染物总量控制研究提供科学依据。

Can short-term and small-scale experiments reflect nutrient limitation on phytoplankton in natural lakes?

Whether it is necessary to reduce nitrogen(N) and/or phosphorus(P) input to mitigate lake eutrophication is controversial. The controversy stems mainly from differences in time and space in previous studies that support the contrasting ideas. To test the response of phytoplankton to various combinations of nutrient control strategies in mesocosms and the possibility of reflecting the conditions in natural ecosystems with short-term experiments, a 9-month experiment was carried out in eight 800-L tanks with four nutrient level combinations(+N+P,-N+P, +N-P, and-N-P), with an 18-month whole-ecosystem experiment in eight ~800-m^2 ponds as the reference. Phytoplankton abundance was determined by P not N, regardless of the initial TN/TP level, which was in contrast to the nutrient limitation predicted by the N/P theory. Net natural N inputs were calculated to be 4.9, 6.8, 1.5, and 3.0 g in treatments +N+P,-N+P, +N-P, and-N-P, respectively, suggesting that N deficiency and P addition may promote natural N inputs to support phytoplankton development. However, the compensation process was slow, as suggested by an observed increase in TN after 3 weeks in-N+P and 2 months in-N-P in the tank experiment, and after 3 months in-N?+P and ~3 months in-N-P in our pond experiment. Obviously, such a slow process cannot be simulated in short-term experiments. The natural N inputs cannot be explained by planktonic N-fixation because N-fixing cyanobacteria were scarce, which was probably because there was a limited pool of species in the tanks. Therefore, based on our results we argue that extrapolating short-term, small-scale experiments to large natural ecosystems does not give reliable, accurate results.

温度敏感型缓/控释肥料的温度响应特征、养分释放性能与温敏机理研究进展

温度是影响缓/控释肥料养分释放特性的重要因素,开发温度敏感型缓/控释肥料可以使肥料养分释放与作物养分需求更加匹配,从而提高肥料利用效率,促进农业可持续发展。本文综述了聚酰胺类、聚醚类、聚酯类、多糖类以及温敏聚氨酯等常见的温敏聚合物材料的来源、类型和机理,详细阐述了聚N-异丙基丙烯酰胺(PNIPAM)、聚N-乙烯基己内酰胺(PNVCL)、环氧乙烷/环氧丙烷嵌段共聚物(EO/PO)、甲基纤维素和温敏聚氨酯等常见温敏聚合物材料用作温敏缓/控释肥料包膜材料的国内外研究进展,并评估了其在温敏缓/控释肥料中应用的可行性与优缺点。根据温敏特性,将温敏缓/控释肥料分为低临界溶解温度(LCST)响应型和结晶转变温度(Tm)/玻璃化转变温度(Tg)响应型两大类,并详细总结了这两种类型的制备方法、特征、养分释放性能以及分子作用机制。最后,指出温敏型缓/控释肥料的研发尚处于初级阶段,未来应深入开展天然高分子温敏材料的基础研究和创新,筛选绿色可生物降解温敏聚氨酯材料,研发作物和区域专用型温敏缓/控释肥料。

控释肥联合养分增效剂显著提高番茄产量与品质

采用田间试验,以番茄(Lycopersicon esculentum Mill.)品种瑞菲为试验材料,通过控释肥联合养分增效剂探究其对番茄生长、产量与品质的影响。结果表明,控释肥联合养分增效剂能显著增加植株茎粗(P<0.05);与常规施肥相比,控释肥和控释肥联合养分增效剂可显著改善番茄品质,番茄果实可溶性固形物含量有增加的趋势,可溶性糖含量、维生素C含量显著提高(P<0.05),番茄果实色泽度和硬度均有所改善;与常规施肥相比,控释肥和控释肥联合养分增效剂能有效提高番茄产量与经济效益,产量分别增加12.7%和29.2%,净利润分别增加3.65万元/hm^(2)和7.72万元/hm^(2)。综上,控释肥联合养分增效剂可实现番茄增产增效,在实现轻简化生产中具有重要的实践价值。

控释尿素配比对华南双季稻产量、氮素吸收累积及氮肥利用率的影响

【目的】探讨2种不同释放期控释尿素不同配施模式对水稻产量、氮素吸收累积及氮肥利用率的影响,以期为我国华南双季稻区优化施氮提供科学依据。【方法】采用田间试验,设6个处理:T1,不施氮处理;T2,速效氮肥单施处理;T3,60 d控释尿素单施处理;T4,90 d控释尿素单施处理;T5,60 d控释尿素配施处理(30%60 d控释尿素+70%速效氮肥);T6,90 d控释尿素配施处理(30%90 d控释尿素+70%速效氮肥)。动态分析不同处理的水稻叶片SPAD值,灌浆后地上部、剑叶、穗部氮含量及干物重;收获期测定水稻产量及产量构成因素;计算不同施肥处理的氮肥利用效率。【结果】由早、晚稻年平均产量可知,施用控释尿素的T3~T6处理较速效氮肥单施的T2处理产量显著增加(P<0.05,下同),增幅为4.7%~8.5%。其中,T5处理产量(5.8 t/ha)最高,显著高于T3和T4处理,但与T6处理差异不显著(P>0.05)。与T1处理相比,施用氮肥提高了早稻剑叶SPAD值,T6处理的剑叶SPAD值一直处于较高水平,且始终高于T5处理,T3处理的剑叶SPAD值总体高于T4处理。T5处理产量较高归因于其有效穗数和穗粒数同时保持较高水平。随着时间的推移,水稻植株地上部氮含量逐渐下降,而干物重逐渐增加,且各处理不同部位干物重存在明显差异,至收获期,T5和T6处理穗干物重均显著高于T2处理,但T5处理地上部氮素累积量相对低于其他施氮处理。各控释尿素处理的氮素表观回收率和氮肥农学效率均显著高于T2处理,其中氮素表观回收率以T3处理最高(35.7%),氮肥农学利用率以T5处理最高(7.3%)。【结论】等氮肥用量下,30%60 d控释尿素配施70%速效氮肥处理在提高籽粒产量和养分利用效率方面具有优势,可作为华南双季稻区的推荐施肥模式。

增施菌剂对玉米产量、土壤养分、光合特性及病虫害的影响

选取4块玉米标准样地,设置了不施肥(CK)、常规施肥(Z_(1))、化肥+西多里微生物菌剂(Z_(2))、化肥+聚谷氨酸复合微生物菌剂(Z_(3))等4个处理,分析了不同菌剂对玉米产量、土壤养分、光合特性及病虫害防治的影响。结果表明:在玉米产量方面,增施菌剂处理后的行粒数、千粒重和产量均高于CK,其中以Z_(3)处理最佳;在土壤养分方面,Z_(1)~Z_(3)处理在拔节期、乳熟期、成熟期的有机质含量均高于CK,以Z_(3)处理为最高;增施菌剂处理后的土壤碱解氮含量均显著高于CK,具体表现为Z_(3)>Z_(2)>Z_(1)>CK;Z_(3)、Z_(2)、Z_(1)处理的土壤速效磷含量在拔节期、乳熟期和成熟期分别是CK的1.78、1.42、1.15倍,1.76、1.48、1.19倍和2.46、1.95、1.47倍;Z_(3)处理的土壤速效钾含量在拔节期、乳熟期和成熟期分别是Z_(2)、Z_(1)处理及CK的1.30、1.17、1.07,1.28、1.19、1.07倍和1.39、1.19、1.09倍;净光合速率和蒸腾速率在乳熟期达到峰值,其中Z_(3)处理的净化光合速率显著高于其他处理,其蒸腾速率分别是Z_(2)、Z_(1)处理及CK的1.51、1.34、1.24倍;在病虫害防治方面,Z_(1)~Z_(3)处理的病株率显著低于CK。综上,增施菌剂可提高玉米产量,改善土壤养分,增强光合特性,减少病虫害,其中化肥+聚谷氨酸复合微生物菌剂的优势最为明显,可在玉米种植中推广应用。

空间低压环境下植物养分吸收与生长特性研究进展

针对月球/火星基地大气压控制一般低于标准大气压(101 kPa)的要求,开展低压环境下植物的养分吸收与生长特性研究有助于对低压下植物的生长差异有更深层次的理解,从而在受控生态生保系统内建立更完善的植物单元体系。综述了近年来国内外低压植物培养实验的主要研究结果,对比分析了低压植物养分吸收与动力学特性的差异,以及对植物生长状态、生物量和基因表达的影响,并对未来的低压植物实验研究方向做出展望。

基于营养琼脂培养基保温后浑浊问题与对策研究

营养琼脂培养基在50℃条件下保温18 h后,会出现浑浊现象,给无菌判定带来困难,同时也会影响菌落计数等微生物实验的准确性。为查明营养琼脂培养基在保温后出现浑浊现象的原因,以提高涉及该培养基的所有实验的准确性,文章通过复融法、磷酸盐沉淀法和初始菌控制法对其原因进行研究分析。实验结果表明,导致营养琼脂培养基在保温过程中出现浑浊现象的主要原因是培养基中初始菌含量过高,在121℃灭菌15 min的条件下无法全部灭活。针对验收过程中出现的保温浑浊问题,可以采用辐照灭菌的方法,将培养基以15~18 kgy的剂量进行辐照灭菌,降低初始菌含量,并在121℃的条件下灭菌15 min。

黄燕之脑、血观

总结介绍黄燕教授对奇恒之腑脑生理特征的见解,主要阐述了脑与血之间的关系。黄燕教授认为,(1)脑主神明,以血为本。人的精神活动由脑所主宰,精神变化与五脏息息相关,脑与五脏在精神活动方面的沟通,是以血为物质基础的。(2)脑统五脏以治血。大脑通过调节五脏的功能来保障血液在机体中运行有序。(3)脑摄血,以化神机。人脑是通过摄纳脏腑供给的营血,在奇恒之腑中化生神机。而神机支配着人体的运动、感知等生理功能。(4)元神为使,营血为守。元神在外,是脑生理功能的体现,营血在内,是脑的物质基础。脑和血关系密切,相互依存,互为根本,相互滋生,促进和助长。

Benefit Assessment of Forest Function in Reducing Soil Erosion and Nutrient Loss in Anji County of Taihu Lake Basin

The non-point source pollution arising from soil erosion is one of the main reasons for the deterioration of the water quality of the Taihu Lake Basin. Forest plays an important role in controlling soil erosion and reducing nutrient loss. Based on the survey data on forest resources in Anji County, we estimate the amount of soil erosion and nutrient loss of nitrogen and phosphorus reduced by forest, using soil erosion modulus method and soil nutrient content. In accordance with the degradation coefficient of pollutant and regional compensation standards of environmental resources, we assess the ecological benefits of forest function in reducing nutrient loss of nitrogen and phosphorus in Anji County. The results show that the forest in Anji County can reduce the soil erosion amount at 1.51 million t annually on the average, so as to control the nutrient loss of 1 409 t of total nitrogen and 577 t of total phosphorus in soil, equivalent to annually avoiding the flow of 824 t of total nitrogen and 410 t of total phosphorus into river water; this ecological service function can make forests in Anji County get 92.55 million yuan of ecological compensation funds (about 688 yuan/hm2·a), equivalent to 15 times of the current ecological compensation standard (47 yuan/hm2). The study reveals the importance of forest function in controlling soil erosion and nutrient loss in the upper reaches of Taihu Lake Basin to water environment protection in the basin, conducive to carrying out pollution control and protection work of the water environment in the basin.

从营卫理论探讨神经内分泌免疫系统紊乱

营卫理论来源于《黄帝内经》,是中医学理论体系的重要组成部分。营、卫二气皆为饮食所化,其精粹部分为营气,剽悍部分为卫气。营气行于脉中,一昼夜运行五十周次,发挥着营养机体的功能;卫气与营气并行,其行于脉外,昼行于阳,夜行于阴,各二十五周,发挥护卫固表、保护机体的作用。营、卫二气联络机体的脏腑与经络,保持内环境的稳态,维护机体的健康。现代医学认为,在控制血脉、调节精神、睡眠、体温、人体防御能力、人体周期律等方面,营卫理论与神经内分泌免疫系统有一定的相关性。营、卫二气运行失常时,机体会发生分子水平上的变化,同神经内分泌免疫系统失调时的一些细胞因子或激素等物质产生变化有一定的相关性。对两者的相关性进行研究,有助于防未病治已病,推动对营卫理论的现代化认识与研究,加强对营、卫二气的进一步认识。