养分专家系统推荐施肥对冬小麦产量、养分转运及肥料利用的影响

为探究冬小麦科学施肥技术,明确养分专家系统推荐施肥对冬小麦产量、养分积累转运与利用的影响,于2018—2019年分别在河南省鹤壁市和新乡市以冬小麦(鹤壁、新乡试验品种分别为‘郑麦7698’和‘郑麦366’)为试验材料,设置7个处理[农民习惯施肥(FP)、当地推荐施肥(ST)、养分专家系统推荐施肥(NE)、在NE基础上配施缓控释氮肥(RNE)、在NE基础上不施氮肥(NE-N)、在NE基础上不施磷肥(NE-P)、在NE基础上不施钾肥(NE-K)],探究不同施肥处理对冬小麦氮、磷、钾养分转运分配规律和肥料利用效率的影响。结果表明,冬小麦氮、磷、钾施肥量NE较FP处理分别降低16.2%、43.3%、-13.2%(鹤壁)和19.5%、48.0%、-57.9%(新乡);冬小麦产量NE与FP处理无显著性差异,RNE与FP处理存在显著性差异;NE、RNE较FP处理分别增产4.7%～6.6%、5.5%～9.6%(P0.05)。进一步研究表明,NE、RNE处理可显著增加地上部植株养分含量和积累量(P0.05),其花后干物质积累量较FP处理增加9.2%～14.0%、11.9%～18.6%;花前氮、磷素转运量和钾素转运对籽粒钾素积累贡献率均有提高,基于养分专家系统推荐施肥的氮、磷、钾肥平均利用效率分别为42.1%、19.2%、46.6%,平均农学效率分别为11.5kg·kg~(-1)、13.2 kg·kg~(-1)、13.3 kg·kg~(-1)。综上可知,小麦养分专家系统指导优化了氮、磷、钾肥的施用量和施用方法,促进了小麦对氮、磷、钾养分的吸收利用,提高了肥料利用率,具有良好的增产效果,可以在河南地区推广应用。     

主要农作物秸秆养分资源现状及其肥料替代潜力分析——以安徽省为例

安徽省农作物秸秆资源丰富,充分利用秸秆养分资源对于农田养分投入的合理分配具有重要意义。评估全省主要农作物秸秆还田当季有效养分替代化肥潜力,可为安徽省减肥增效提供科学依据。本研究以安徽种植面积较大的主要农作物水稻、小麦、玉米、大豆、花生和油菜为研究对象,通过查阅安徽省统计数据和公开发表的文献资料,对2017年安徽省主要农作物秸秆数量、秸秆还田率以及还田当季养分利用率进行估算,明晰了全省化肥减施潜力。结果表明:2017年安徽省主要农作物秸秆资源量为4 699.9万t,秸秆资源分布上呈北部和中部较多、南部最少的特征。秸秆养分资源总量为124.8万t,N、P_2O_5和K_2O分别为38.1万t、11.4万t和75.3万t,分别占全省主要农作物养分需求的40.1%、32.1%和68.9%。理论上,秸秆全量还田,且养分充分利用的情况下,秸秆养分替代化肥潜力大。但秸秆养分N、P_2O_5和K_2O当季利用率分别为38.9%、52.3%和69.9%,实际秸秆N、P_2O_5和K_2O养分还田量仅占主要农作物养分需求的15.6%、16.8%和48.2%,分别占农田养分总投入量的8.6%、6.4%和41.4%。通过秸秆还田,全省可减施化肥63.3万t,减施比例为19.8%, N、P_2O_5和K_2O减施比例分别为11.4%、17.2%、40.7%。进一步提高秸秆还田率和当季养分释放率,是推进全省化肥减施增效的有利手段。     

农地确权对小农户信贷可得性的影响——基于双稳健估计方法的平均处理效应分析

基于我国9省小农户调查数据,运用双稳健的平均处理效应模型,研究了农地确权对小农户信贷可得性的影响及其作用机理。结果表明:农地确权可以提升小农户信贷可得性。进一步研究发现,需求方面的影响路径是:确权提高了小农户的土地安全性,增加了农业长期投资,并提高了信贷意愿。供给方面的影响路径是:确权增加了小农户的财产权并使其拥有了可流转大额财产,传递了还款可能性增加的信号;而且可将农地作为抵押品获得农地抵押贷款,增加了金融机构的贷款供给。不过,农地的信号传递作用大于抵押作用,农地抵押作用的发挥需要进行进一步的制度和组织创新。     

生物炭对不同酸化水平稻田土壤性质和重金属Cu、Cd有效性影响

针对南方稻田土壤酸化严重,导致养分流失有毒重金属活化,严重影响稻米质量安全的重大现实问题。以水稻秸秆和谷壳等农业废弃物为原料制备生物炭(分别记为RSC和RHC),研究不同原料生物炭对酸化土壤改良及其对重金属有效性的影响。设置3个生物炭用量(0,20,50 g/kg,分别记为CK、C1、C2),4种土壤酸化水平(pH 4.01,4.25,4.33,4.58,分别记为L1、L2、L3、L4),生物炭与重金属污染土壤共同培养60天后测定土壤pH、全氮、有机质、有效磷、速效钾和有效态Cu、Cd含量。结果表明:RSC对酸化土壤pH的改良效果明显优于RHC,且施炭量越高提高幅度越大,RSC的C2处理使4种酸度水平的土壤pH分别提高了0.68,0.97,1.29,1.71个单位。2种生物炭均能提高土壤的全氮、有效磷、速效钾和有机质含量,其中各施炭处理有机质显著提高,尤以速效钾的增幅最为显著,RSC对4种养分的提高均优于RHC。RHC对土壤有效态Cu含量无显著影响;RSC的C2较C1处理更能降低土壤中有效态Cu含量,使4种酸度水平的土壤分别降低了13.62%,6.57%,4.36%,7.88%。RHC处理的L3、L4土壤中有效态Cd含量显著降低,最大分别降低了13.79%,19.23%。RSC使4种酸度土壤有效态Cd含量最大分别降低了20.00%,25.81%,20.69%,19.23%。相关分析表明,土壤pH与有效态重金属含量呈显著负相关关系。水稻秸秆炭用于改良酸化土壤、降低重金属Cu和Cd有效性的效果更佳,且降低污染土壤中Cd的有效性较Cu好;生物炭对酸化程度越低的土壤pH和有效磷含量的提高以及有效态Cd含量的降低效果较好,而有效态Cu含量的降低效果则在酸化程度越高的土壤中表现更佳;土壤pH是生物炭调控重金属Cu、Cd有效性的主要影响因素。     

Effect of soil pore size distribution on plant-available water and least limiting water range as soil physical quality indicators

Soil pore size distribution(SPSD) is one of the most important soil physical properties. This research investigated the relationships of location and shape parameters of the SPSD curves with plant-available water(PAW) and least limiting water range(LLWR) of the light-textured soils at the Torogh Agricultural Research Station in north-eastern Iran. Soil moisture release curve(SMRC), PAW and LLWR in matric heads of 100 and 330 h Pa for the field capacity and location and shape parameters of the SPSD curves of 30 soils with different texture and organic carbon contents were determined, and the variable relationships were statistically analyzed. The results showed that the median equivalent pore diameter(de), mean de, standard deviation(SD*), and skewness of the SPSD curves were significantly correlated with PAW(PAW330) and LLWR(LLWR330) measured in a matric head of 330 h Pa. Decrease in deand increase in the diversity of soil pore size(SD*) increased PAW330 and LLWR330. The SD* values of all the soil samples were lower than the optimal ranges suggested in literature. Neither PAW nor LLWR values were significantly different in the soils with the optimal modal deand those with non-optimal modal de. Optimal values of median and mean equivalent pore diameters and kurtosis of SPSD curves led to a significant improvement of PAW330 and LLWR330 as soil physical quality indicators. It was recommended to revise the optimal ranges for SD* and modal defor future studies.     

养分管理对安溪茶园土壤肥力及茶叶品质的影响

安溪是铁观音的主产区,茶园养分管理滞后已成为该地区茶叶生产的瓶颈,本研究旨在为该地区茶园的养分管理提供科学依据。试验于2015年在安溪县采集了50个茶园的茶青与土壤样品,测定了土壤5项主要肥力指标和茶青中9种主要次生代谢物含量;并根据茶农氮肥用量调研数据,初步将茶园养分管理划分为:少量、中量和过度型等三种方式。限制性主坐标轴分析发现,此分类方式可解释34.4%(P0.001)茶园土壤肥力参数的总体差异,说明此分类方式能反映出不同茶园养分管理的总体水平;并且,养分管理对表层土壤有效磷的影响最为显著。进一步分析表明,养分管理对茶青综合品质的影响可解释品质总差异的7.48%(P0.001);大部分茶青次生代谢物在中量型管理下含量最高。说明养分管理影响安溪茶园土壤的肥力状况,施肥量过高或过低均不利于高品质茶叶的生产,该地区的建议施氮量约为200～400 kg·hm~(–2)·a~(–1)。     

Comparative study on the effects of buckwheat by roasting: Antioxidant properties,nutrients, pasting,and thermal properties

The increasing need to prolong the shelf life of buckwheat has prompted the use of roasting techniques in buckwheat processing. For effective roasting, the responses of common buckwheat (CB) and tartary buckwheat (TB) to the process should be explored. Herein, the antioxidant properties, nutrients, pasting, and thermal properties of raw and roasted buckwheat flours (roasted at 200 °C for 50 s) from two CB and three TB varieties were investigated. Results showed that roasting considerably reduced the total flavonoid content (TFC) and total phenolic content (TPC) of TB. The TPC of CB was significantly improved by roasting, whereas the TFC significantly decreased. The total antioxidant capacities were consistent with the TPCs. Additionally, the colour deepened as the amount of antioxidant compounds increased. Unexpectedly, roasting enhanced the protein and fat contents of CB and decreased those of TB. Roasting improved the nutritional quality and antioxidant capacity of CB, and opposite results were obtained in TB. In conclusion, CB was more suitable to the development of roasted specialty products with nutritional applications than TB. We suggest that differences among varieties should be considered first in the buckwheat roasting process.     

安徽省作物养分供需分析及化肥减施潜力研究

有机-无机相结合的农田养分管理模式是现阶段中国发展绿色农业的必由之路,因而开展有机、无机养分和作物养分需求的比较研究对促进养分资源的合理分配和施用具有重要的参考价值。本文采用文献调查和统计分析的方法,评估了安徽省16市2010—2016年主要有机肥(包括秸秆、粪便、绿肥和饼肥)的养分资源,明晰了安徽省农业生产中有机、无机养分投入现状,并根据农业种植结构开展了有机、无机养分和作物养分需求的差异和关系研究,最后探索了安徽省的化肥减施潜力。结果表明:安徽省2010—2016年平均有机肥养分资源为287.70万t,N、P_2O_5和K_2O分别为104.49万t、39.60万t和143.61万t,可基本满足作物的养分需求;但有机肥的当季利用率低,N、P_2O_5和K_2O的当季利用率分别为21.44%、19.91%和52.61%,有机肥N、P_2O_5和K_2O实际还田量仅占作物养分需求的20.74%、25.38%和63.61%,占农田养分总投入的比重分别为11.87%、10.27%和51.35%。全省N、P_2O_5、K_2O养分实际投入量(包括有机肥和化肥)是作物养分需求的1.75倍、2.47倍和1.24倍,有7个市的N和13个市的P_2O_5养分施用量超过作物需求的2倍,存在较高的环境污染风险。通过控制农业总养分输入,安徽省的化肥减施潜力为35.12%,N、P_2O和K_2O的减施潜力分别为21.28%、23.97%和78.61%。提高有机肥的当季利用率和发展冬季绿肥资源可进一步促进化肥减施。本研究可为安徽省化肥零增长和农牧业的绿色可持续发展提供数据参考。     

Combined effects of water temperature and daily food availability period on the growth and survival of tench (Tinca tinca) larvae

A 16‐day experiment was designed to find the best combination of water temperature (27, 30, 33°C) and daily duration of food availability (12, 18, 24 h) for larval tench (Tinca tinca) growth and survival. Larvae with an initial mean size of 5.7 mm total length (TL) and 0.7 mg wet body weight (BW) were stocked at 15 L^?1. Larvae were fed in excess with live Artemia nauplii with the period of food availability lasting 12, 18 or 24 h daily. The largest final larval size was recorded at 27 and 30°C in groups fed for 24 h a day (17.7 and 17.9 mm TL, 76.1 and 77.7 mg BW, respectively). The combination of the highest temperature and the longest daily food availability was the only set of conditions under which final larval survival was affected (95.4% survival; 98.7–99.9% under all other conditions). The combination of water temperature of about 28.6°C and continuous food availability is recommended as the optimum combination for rearing T. tinca larvae under controlled conditions. Providing continuous food supply to fish larvae under aquaculture conditions was also advantageous in helping to mitigate the effects of slower growth relative to developmental progress, which can occur at high water temperatures. However, should one wish to limit the daily feeding period to 12 h per day, the use of a water temperature between 27.4 and 27.9°C would be the best solution.     

砂田甜瓜套作向日葵系统的养分利用研究

2010—2013年在庄浪县进行的砂田甜瓜套作向日葵系统的养分利用研究的结果表明,无论在甜瓜的初花期、座果期、膨大期套作食葵或油葵,套作系统比单作明显提高了作物的吸氮量、吸磷量和吸钾量。氮吸收量比单作增加50%~59%,磷吸收量比单作增加12%~41%,钾吸收量比单作增加33%~68%。