不同增稠剂对农药可分散油悬浮剂稳定性的影响

为明确不同增稠剂对以矿物油为分散介质的油悬浮体系稳定性的影响,以12.5%丙炔·吡嘧(丙炔噁草酮·吡嘧磺隆)可分散油悬浮剂为对象,通过流变学和多重光散射方法,研究了有机膨润土、有机高分子和气相二氧化硅3类增稠剂单独使用及有机膨润土和其他两类增稠剂分别搭配使用对可分散油悬浮剂物理稳定性的影响。结果表明:所有样品的流动特性指数(n)均小于1,为假塑性流体,具有触变性。除有机膨润土和高分子增稠剂Atlox Rheostrux100组合使用时体系更符合Casson方程外,其余样品均更符合Herschel-Bulkley方程。单独使用时,有机膨润土对保证体系稳定的效果相对较好;Atlox Rheostrux 100和Atlox Rheostrux200两种高分子增稠剂的效果差别较大,其中Atlox Rheostrux 100效果更好,这可能是由分子结构差异造成;两种气相二氧化硅类增稠剂由于不能有效形成氢键,效果较差。将有机膨润土和有机高分子增稠剂组合使用时,体系的稳定性有所提升,其中有机膨润土869和Atlox Rheostrux 100组合使用效果更好,体系具有较高的黏度,且具有良好的触变性,物理稳定性优异;有机膨润土869和疏水气相二氧化硅R974组合使用时则效果没有明显的提升。研究表明,流变学和多重光散射两种方法均能较好地表征可分散油悬浮剂的物理稳定性;新型高分子增稠剂和有机膨润土具有协同作用,将二者合理组合添加能大幅提升可分散油悬浮剂的稳定性。     

Potassium accumulation,partitioning, and remobilization in high-yield spring maize in Northeast China

Potassium (K) plays an important role in maize yield, but K accumulation characteristics in high yielding maize is still not well documented. A two-year field experiment was conducted to investigate the K accumulation characteristics of high yield (HY)（>15 t ha^?1）spring maize compared with medium yield (MY)（10–15 t ha^?1), and low yield (LY)（<10 t ha^?1). The maximum K accumulation stage in maize appeared between V6 and V12 stage (LY, MY, and HY was 125.46, 138.05, and 146.22?kg ha^?1, respectively). Most of the K (94.27–97.13%) was accumulated during vegetative stages. HY exhibited a significantly higher K accumulation than either MY or LY. For different organs, the K remobilization amount of leaf was the highest, and the remobilization amount of stalk was the lowest, the K remobilization amount of leaf and stalk showed as HY?<?MY?<?LY, same as the total K remobilization amount, but the K remobilization amount of sheath and husk plus cob showed the opposite order. These results indicated that sufficient nutrient supply for maize can not only accumulate more K but also delay leaf senescence and maintain high photosynthetic activity, resulting in reduced K remobilization from vegetative organs, and reduced K loss in whole plant.     

Substitution of chemical fertilizer by Chinese milk vetch improves the sustainability of yield and accumulation of soil organic carbon in a double-rice cropping system

The double-rice cropping system is a very important intensive cropping system for food security in China. There have been few studies of the sustainability of yield and accumulation of soil organic carbon(SOC) in the double-rice cropping system following a partial substitution of chemical fertilizer by Chinese milk vetch(Mv). We conducted a 10-year(2008–2017) field experiment in Nan County, South-Central China, to examine the double-rice productivity and SOC accumulation in a paddy soil in response to different fertilization levels and Mv application(22.5 Mg ha~(–1)). Fertilizer and Mv were applied both individually and in combination(sole chemical fertilizers, Mv plus 100, 80, 60, 40, and 0% of the recommended dose of chemical fertilizers, labeled as F100, MF100, MF80, MF60, MF40, and MF0, respectively). It was found that the grain yields of double-rice crop in treatments receiving Mv were reduced when the dose of chemical fertilizer was reduced, while the change in SOC stock displayed a double peak curve. The MF100 produced the highest double-rice yield and SOC stock, with the value higher by 13.5 and 26.8% than that in the F100. However, the grain yields increased in the MF80(by 8.4% compared to the F100), while the SOC stock only increased by 8.4%. Analogous to the change of grain yield, the sustainable yield index(SYI) of double rice were improved significantly in the MF100 and MF80 compared to the F100, while there was a slight increase in the MF60 and MF40. After a certain amount of Mv input(22.5 Mg ha~(–1)), the carbon sequestration rate was affected by the nutrient input due to the stimulation of microbial biomass. Compared with the MF0, the MF100 and MF40 resulted in a dramatically higher carbon sequestration rate(with the value higher by 71.6 and 70.1%),whereas the MF80 induced a lower carbon sequestration rate with the value lower by 70.1% compared to the MF0. Based on the above results we suggested that Mv could partially replace chemical fertilizers(e.g., 40–60%) to improve or maintain the productivity and sustainability of the double-rice cropping system in South-Central China.     

科尔沁草甸湿地土壤碳氮剖面分布及生长季动态特征

采用定位观测的试验方法,于2016年5-10月及2017年8月对科尔沁草甸湿地0~100 cm土层土壤有机碳、全氮剖面分布及生长季动态特征进行了实验分析,旨在为科尔沁草甸湿地保护提供科学指导并为干旱半干旱地区湿地土壤碳氮储量估算提供借鉴。结果表明:1)科尔沁草甸湿地土壤有机碳、全氮含量整体随土层深度下降,0~20 cm土层间下降显著,20 cm以下趋于相对稳定,范围分别为11.9~23.5 g·kg^-1和0.66~1.50 g·kg^-1。2)各土层土壤碳氮含量月间差异显著(全氮40~60 cm土层除外),变化幅度随土层深度先减小后增大;土壤碳氮密度(100 cm)生长季变化大于年际变化,有机碳密度全生长季呈上升趋势,范围为15.44~20.82 kg·m^-2,全氮密度生长初期明显下降,之后趋于相对稳定,范围为1.01~1.16 kg·m^-2。3)土壤有机碳含量与全氮含量呈极显著正相关;植被和水文是影响其分布、变化的关键因子。科尔沁草甸湿地生长季土壤有机碳、全氮密度变化较大,且表现为潜在的碳汇和氮源,但年际间碳汇潜力未充分发挥,本研究建议禁牧力度应加大并增加氮肥投入以提高科尔沁草甸湿地生态系统功能。     

长期施肥处理对双季晚稻叶绿素荧光特征及籽粒产量的影响

研究施肥模式对水稻叶绿素含量及荧光参数的调节作用,对提高水稻光能利用效率及籽粒产量具有重要意义。本研究以水稻品种赣929为试验材料,比较长期定位施磷钾肥(PK)、施氮磷钾肥(NPK)、等养分条件下70%氮磷钾肥配合施用30%有机肥(70F+30M)、50%氮磷钾肥配合施用50%有机肥(50F+50M)、30%氮磷钾肥配合施用70%有机肥(30F+70M)条件下水稻叶绿素荧光参数和产量变化特征。结果表明,水稻旗叶叶绿素含量从齐穗期到成熟期呈下降趋势,且表现为30F+70M50F+50M70F+30MNPKPK。水稻叶绿素荧光参数Fv/Fm随水稻生育期的推进呈降低趋势,其中PK处理Fv/Fm值最低,而施氮处理比不施氮处理Fv/Fm值增加了2.85%～4.18%。叶绿素荧光参数qL、ΦPSII在NPK处理中表现为齐穗期较高, 20 d之后显著降低;在50F+50M、30F+70M处理中表现为齐穗期较低, 20 d以后显著增加;在PK处理、70F+30M处理中一直处于较高水平。NPQ变化趋势与qL基本相反。ETR-PAR光响应曲线拟合结果表明, 70F+30M处理ETRmax、?和Ek值在齐穗期和20 d后值均最高。综合看来,等养分条件下配施30%有机肥具有最优的叶绿素荧光指标组合及籽粒产量;而配施超过50%有机肥由于前期热耗散增大使得用于光合作用的光能份额减少,而施用氮磷钾肥处理则由于后期的衰老使得光能利用效率下降。     

氮磷钾用量对小麦冠层不同层次光截获和干物质分配的影响

为明确不同氮、磷、钾用量对小麦冠层不同层次光截获和干物质分配的影响，以济麦22为供试材料，设置F0（不施肥）、F1（N 180 kg·hm^-2，P₂O₅ 75 kg·hm^-2，K₂O 60 kg·hm^-2）、F2（N 225 kg·hm^-2，P₂O₅ 120 kg·hm^-2，K₂O 105 kg·hm^-2）和F3（N 270 kg·hm^-2，P₂O₅ 165 kg·hm^-2，K₂O 105 kg·hm^-2）4个施肥量处理，比较分析开花后不同氮、磷、钾用量对小麦叶面积指数、冠层不同层次光截获特性和成熟期干物质分配的影响。结果表明，F1处理下叶面积指数显著高于F0处理，而与F2和F3处理间无显著差异；开花后15 d，F1处理下小麦冠层不同层次及总PAR截获率和截获量均显著高于F0处理，而与F2和F3处理间无显著差异。F1处理下成熟期干物质在小麦冠层不同层次营养器官中的分配量、籽粒中的分配量及总干物质积累量显著高于F0处理，而与F2和F3处理间无显著差异。成熟期干物质在小麦冠层不同层次营养器官和籽粒中的分配量以及总干物质积累量与冠层上层（顶部至株高2/3）、中层（株高2/3至株高1/3）和总PAR截获率均呈显著正相关。F1处理（N 180 kg·hm^-2，P₂O₅ 75 kg·hm^-2，K₂O 60 kg·hm^-2）为本试验条件下的最优处理。     

虾肽有机肥与磷肥配施对苹果产量和品质的影响

[目的]研究虾肽有机肥(SPOF)与磷肥配施的协同增效作用。[方法]采用田间小区试验,设尿素1.4 kg/株(CK)、尿素1.4 kg/株+农家肥50 kg/株+磷酸二氢钾1.54 kg/株(TT1)、尿素1.4 kg/株+SPOF 30 kg/株+磷酸二氢钾1.54 kg/株(TT2)、尿素1.4 kg/株+SPOF 30 kg/株+普通过磷酸钙0.83 kg/株+磷酸二氢钾1.25 kg/株(TT3)。[结果]各处理的产量TT3>TT2>TT1>CK,且TT3达到了显著水平;TT3的品质指标,即可溶性固形物、维生素C、蔗糖、葡萄糖以及硬度均达到了显著水平。[结论]TT3处理虾肽有机肥和磷肥(SSP+KH2PO4)协同将其效力发挥到最大。     

华北地区夏玉米生产中磷素利用特征研究

为评估当前中国华北地区夏玉米生产中的磷素利用效率和影响因素,促进磷肥资源高效利用和降低损失和污染,本研究通过收集1980年以来公开发表的夏玉米田间试验的文献,对华北地区夏玉米磷肥试验数据进行收集、整理和分析,获得了夏玉米的籽粒与秸秆产量及其比例,以及施磷量与籽粒和秸秆磷含量的关系模型。研究发现,随着施磷量的增加,土壤-夏玉米作物系统的磷素表观盈亏量呈线性增加,在施磷达到75 kg/hm ²时,磷素表观盈亏量为0。华北地区的夏玉米磷肥平均利用效率约为15%;增加氮肥施用量以及与磷合理配施有利于提高磷肥利用效率。整体上,夏玉米对磷酸二铵的利用效率高于过磷酸钙;有机肥和化肥配施可以有效提高磷肥利用效率。夏玉米‘天泰60’品种的磷肥利用效率最高。在华北地区夏玉米生产中,选用磷酸二铵以及适合的氮肥水平、有机肥与化肥配施,可以提高磷肥利用效率,降低磷肥损失和环境污染风险。