Spatial Dynamics of Water and Nitrogen Management in Irrigated Agriculture

Dynamic optimization of crop production with nonuniform irrigation and nitrogen carryover and leaching is considered. A production function system with thresholds, plateau maximum, and yield reduction is estimated from experimental data; rapid convergence to a steady-state is observed. Spatial variability implies a 40% increase in applied water and a six-fold increase in nitrate emissions, while dynamic optimization has more modest impacts. Nitrate emission control is accomplished primarily through reduced applied water, illustrating a strong cross-policy effect. Significant levels of water conservation and nitrate pollution control are achieved at relatively low cost with traditional irrigation systems and baseline conditions.     

哈尔滨市设施蔬菜土壤硝酸盐污染改良剂的应用效果研究

针对哈尔滨市辖区部分设施蔬菜土壤硝酸盐污染现状,在五常市五常镇、香坊区光明村蔬菜基地开展硝酸盐污染改良剂的应用研究,通过田间小区试验,研究4种改良剂产品对种植土壤硝酸盐、硝态氮含量,番茄产量、硝酸盐含量及品质的影响。结果表明:4种处理对土壤中硝酸盐和硝态氮含量影响均呈现明显下降趋势,较对照(CK)达显著水平,其中腐植酸+EM菌+双氰胺(HA+EM+DCD)处理效果最为显著,其次为处理EM+DCD、HA+DCD和DCD;番茄产量HA+EM+DCD处理效果最为显著,两地番茄产量为106.11kg/20m2和97.26kg/20m2,比CK增产11.2%和21.7%,达到显著性差异(P0.05);4种处理对番茄中硝酸盐含量降幅均达40%以上,处理EM+DCD、HA+EM+DCD好于处理DCD、HA+DCD,并达显著差异水平;3种处理对番茄Vc、可溶性糖含量及糖酸比均有促进作用,显著改善番茄品质,试验效果HA+EM+DCDHA+DCDEM+DCD。综合评价,改良剂的试验效果依次为HA+EM+DCDHA+DCDEM+DCDDCD。     

氨合成危险工艺自动化控制改造的设计及探讨

随着科技的日新月异,自动化控制在化工生产中的发挥的作用不断增强,全国上下展开了合成氨生产装置工艺自动化控制改造。本论文仅对氨合成工段的改造进行探讨。     

磁场对氨水鼓泡吸收的强化作用

设计了磁场强化氨水鼓泡吸收试验台并在此基础上研究了静止和旋转磁场及纳米磁流体对氨水鼓泡吸收的影响。通过对氨水鼓泡吸收的吸收率和有效吸收比分析发现磁场和纳米磁流体对氨水鼓泡吸收均有强化作用,而旋转磁场的强化效果比静止磁场更为明显。定义了旋转强化吸收量(ARMF)的概念以表征在其他条件相同时磁场的旋转对氨水鼓泡吸收的强化影响。在不同磁感应强度下ARMF的值均大于0,说明磁场的旋转对氨水鼓泡吸收均有强化作用。最后探讨了实验中出现结果的可能机理。     

太平沟流域综合治理工程对农用土壤N素循环及其增产的影响

本文就太平沟流域综合治理工程对促使Ｎ素趋于良性循环原因进行了分析与研究，并对Ｎ素收支平衡对作物产量的影响效果进行了探讨。     

防结块工业硝酸钾新工艺的应用研究

1万t防结块工业硝酸钾的生产装置选用硝酸镁与氯化钾为原料,采用新研究开发的复分解循环反应法生产硝酸钾新工艺,副产品为六水氯化镁,六水氯化镁含少量硝酸钾,故称之为氮钾镁肥。简要介绍了生产装置的工艺原理流程、主要设备选型、产品质量、主要经济技术数据、"三废"防治等。本生产投资少,成本低,产品附加值高。     

论储粮技术有利于粮仓防火安全

灭火系统不论是人工操作的消火栓系统或自动动作的喷水灭火系统、水喷雾灭火系统和气体灭火系统,无一例外的都是在火灾发生后,灭火系统才进行扑救,这种方式必然存在火灾损失,同时还伴随有水渍损失和污染损失。而防火系统则是使火灾不能发生,从而将防火从被动、消极状态转化为主动、积极状态。如何在粮食仓库采用防火而不是灭火？通过对燃烧条件的分析,结合粮食储粮技术情况,论述了现代储粮技术有利于粮库的安全防火。     

Is Site-Specific Yield Response Consistent over Time? Does It Pay?

This study examines the profitability and stability of site-specific (SS) nitrogen fertilizer recommendations using an empirical model of SS yield response to controlled inputs, stable site characteristics, and time-varying weather factors. Using a three-year panel of on-farm corn yield experiments and new, continuous variables to describe site characteristics, both spatial and ordinary least squares regression models show clear evidence of SS corn yield response to nitrogen fertilizer. Yield response is predictable only on irrigated fields. Even there, bootstrapped confidence intervals for profitability gains on selected fields indicate that SS nitrogen application would rarely cover its costs.