Biochar addition mitigates nitrogen loss induced by straw incorporation and nitrogen fertilizer application

Biochar has been shown to be potentially beneficial for enhancing yields and soil properties, and diminishing nitrogen (N) losses. However, it remains unclear how biochar regulates soil carbon (C) and N to mitigate N losses induced by straw mixing with N fertilizer in dryland soils. Therefore, we investigated the effects of straw mixing (S₁), S₁ with biochar (SB) and no straw inputs (S₀), and routine urea application rates (N₁) and 70% of routine rates (N_0.7) on yields and N losses, and identify the relationship between N losses and soil C and N compounds. Results showed that N_0.7 and N₁ were suitable for the maize and wheat seasons, respectively, contributing to mitigating N losses without reducing crop yields. Moreover, in the maize season, N_0.7-SB significantly mitigated the straw-induced NH₃-N and N₂O-N emissions by 106% and 81%, respectively. In the wheat season, N₁-SB reduced the straw-induced NH₃-N and N₂O-N emissions by 35% and 66%, respectively. In addition, N_0.7-SB sharply reduced soil inorganic N (SIN) storage in the maize season. Furthermore, the NH₃-N and N₂O-N emission rates were negatively correlated with dissolved organic carbon/SIN content (0–20 cm) (DOC/SIN_0-20). N losses (N₂O-N and NH₃-N emissions and SIN storage) were positively correlated with SIN_0-20, but negatively correlated with soil organic carbon / SIN_0-20 (SOC/ SIN_0-20). This study provides further evidence that biochar with an appropriate N application rate decreased SIN_0-20 and increased DOC/SIN_0-20, thus reducing SIN storage and the straw-induced gaseous N emissions without decreasing crop yields.     

大型薄壳制件真空辅助树脂传递模塑工艺充模方案仿真分析及优化

针对大型树脂基复合材料制件不适于用实验试错法进行充模方案设计的问题,在分析树脂流动规律的基础上将大型薄壳件的求解区域分解,仿真分析了不同充模方案下树脂在纤维中的流动行为和模腔内压力变化,提出在制件填充面积等分处设置流道的方法,选择和优化大型薄壳制件的充模方案。结果表明:①对于不便进行实验试错法进行真空辅助树脂传递模塑(VARTM)工艺充模方案设计的大型薄壳制件,可以采用数值模拟的方式,以达西定律、能量守恒定律等为计算依据,求解压力场和速度场,对比不同仿真方案的充模时间等数据合理安排注胶方式方法,指导VARTM工艺制备大型复合材料制件合理安排注胶方式,提高生产率、减少因树脂浸润不均匀产生的缺陷。②对于大型薄壳类制件,忽略厚度方向尺寸,影响充模时间的主要因素为流道长度和树脂流动距离。选取尽可能长的注胶流道,合理设置流道位置以减少树脂流动的距离;长流道可以增加树脂瞬时注入量、提高较长时间的压力差;而树脂流程越长,树脂前锋处压力损失越大,流速越慢。③试验提出了制件填充面积等分处设置流道的方法。将大型薄壳工艺制件充模面积等分,注胶流道布置在垂直于制件长度方向的面积等分线上,可缩短充模时间并减少制件两端的树脂富集现象。对于较狭长部分可再次进行面积等分设置流道,以免造成树脂流程过长压力流失过多;而对于较宽阔部分不宜设置过多流道以免树脂前锋稳定前互相接触造成制件充模不均匀。     

抗虫棉品种苏棉6039的选育

介绍了苏棉6039的选育过程和方法、特征特性以及栽培技术要点。     

不同氮肥施用量对胶东卫矛氮代谢生理影响的研究

分析氮对胶东卫矛氮代谢生理的影响规律,明确氮肥施用后的相关酶活性变化机理,为其育苗中科学施用氮肥提供理论依据。试验在田间条件下,设置氮肥施用量分别为0 g/株(J1,CK)、9 g/株(J2)、18 g/株(J3)、27 g/株(J4)4个处理,3次重复。结果表明：5—9月J3谷草转氨酶活性分别比J1提高了64.84%、70.77%、58.52%、47.33%、57.20%,J4与J3之间无显著差异;6—9月J3谷丙转氨酶活性分别比J2提高了18.00%、30.79%、16.47%、16.83%,差异显著;谷胺酰胺合成酶活性7、9月J3显著高于J2,5—6月J2、J3、J4之间无显著差异,J2显著高于对照;5—9月J3硝酸还原酶活性分别比J2提高了20.47%、31.66%、27.32%、23.50%、34.90%,差异显著,J3与J4之间无显著差异;5—7月J3硝态氮含量分别比对照提高了73.76%、53.90%、85.95%,差异显著,8—9月J2、J3、J4之间无显著差异;6—8月,J3可溶性蛋白含量分别比J2提高了15.90%、20.09%、9.04%,差异显著。综合分析认为,J3处理可以显著提高胶东卫矛氮代谢相关酶活性,提高植株叶片内硝态氮含量和可溶性蛋白含量,效果优于J2、J4处理。     

施氮量对一年生黑麦草光合特性的影响

为了探究不同施氮量对一年生黑麦草(Lolium multiflorum Lamk.)光合特性的影响。本研究以‘特高’宽叶型一年生黑麦草为供试材料,采用盆栽试验,设置了4个处理组,分别为:CK对照组(不施肥)、C1低氮处理组(施鸡粪0.38 kg/m^2,即氮100 kg/hm^2)、C2中氮处理组(施鸡粪0.76 kg/m^2,即氮200 kg/hm^2)、C3高氮处理组(施鸡粪1.34 kg/m^2,即氮350 kg/hm^2)。利用Li-6400便携式光合仪测定开花期一年生黑麦草叶片的主要光合参数和光合特性的变化。结果表明:200 kg/hm^2施氮水平的表观量子效率(apparent quantum yield,AQY)和光饱和点(light saturation point,LSP)最高(分别为12.80 μmol·m^-2·s^-1和1 774.47 μmol·m^-2·s^-1),光能利用区间最大。350 kg/hm^2施氮水平下气孔导度(stomatal conductance,Gs)以及蒸腾速率(transpiration rate,Tr)显著低于其它处理,水分利用力(water use efficiency,WUE)强,但光呼吸速率(photorespiratory rate,Pr)较高,不利于干物质积累。同时,0?200 kg/hm^2施氮范围内,随着光照强度和CO2浓度的增加,各处理的净光合速率(net photosynthetic rate,Pn)均随之增加,但350 kg/hm^2施氮水平下叶片净光合速率的增加反而低于200 kg/hm^2施氮水平。合理的施氮量对黑麦草的光响应和CO2浓度响应曲线有明显的调节作用。在本试验条件下,施氮量为200 kg/hm^2最佳。     

Spatio-temporal pattern evolution and spatial spillover effect of green development efficiency: Evidence from Shandong Province,China

Improving green development efficiency is urgently required, yet challenging, since it comprehensively reflects the bidirectional evolutionary relationship between regional development and resource and environmental consumption. The issue of regional green development efficiency has become a key topic; however, where the increase in efficiency originates and its spatial spillover effect remains unclear to date. Therefore, the spatial spillover effect of the green development efficiency of Shandong Province was quantified through the slack variable (SBM)-Undesirable and Spatial Durbin model. The green development efficiency showed clear spatial differentiation in Shandong Province. This was more obvious than the polarized development trend of the provincial capital circle that has Jinan at its core and the eastern coastal region with Qingdao at its core. Green development efficiency has a significant spatial spillover effect. The regression coefficient of the direct effect of the economic development level is positive. The regression coefficient of the indirect effect of the marketization level and government financial support level is negative. Science and technology played a positive role in the promotion of the green development efficiency of local and neighboring cities. This study contributes empirical evidence to the green development efficiency associated with regional development and resource and environment consumption of Shandong Province.     

作物生长季地表及耕作层地温的变化特征

为了研究辽西山区小流域地表及耕作层温度变化状态,从气候角度出发,运用气候倾向率等分析方法,分析了建平丘陵山区1959—2012年作物生长季地表温度、耕层温度变化趋势和特征。结果表明：建平的南、北部地表、耕层温度因地域性相差2.2℃,4—10月地表、耕层温度呈明显增加趋势,南部气候倾向率分别为0.288℃/10 a和0.248℃/10 a;北部气候倾向率分别为0.309℃/10 a和0.312℃/10 a。异常高温年出现在20世纪90年代之后,而异常低温年则出现在20世纪80年代之前。南部地表、耕层温度升高过渡区间在1981—1993年,1994年突变;北部过渡区间在1981—1996年,1997年突变。研究结果对辽西山地小流域治理,气候资源利用开发,合理安排农业生产提供参考。     

Identification of quantitative trait loci for agronomic and physiological traits in maize (<Emphasis Type="Italic">Zea mays</Emphasis> L.) under high-nitrogen and low-nitrogen conditions

Low-nitrogen (LN) tolerance is a compound character with a complex genetic basis. Many agronomic traits have been shown to be closely related to LN tolerance in maize. In this study, 150 F₇ recombinant inbred lines derived from a cross between inbreds 178 and K12 were evaluated for agronomical and physiological traits under high-nitrogen (HN) and LN conditions in 2 years. Inclusive composite interval mapping (ICIM) was used to identify the quantitative trait loci (QTLs) for traits recorded under different treatments (LN and HN) in 2 years. In total, 86 QTLs were detected: 38 for HN and 35 for LN, while 13 QTLs were detected under both nitrogen levels, suggesting that LN-specific QTLs may play a role in improving LN tolerance in maize. Overlapping QTLs for different traits were located on all chromosomes except chromosome 4 and chromosome 9. Many of these regions overlapped with previously reported QTLs. Several consensus major QTLs and LN-specific major QTLs found in the study can be used in marker-assisted selection breeding for genetic improvement and LN tolerance in maize in the future.     

哈尔滨农民回迁居住区户外景观设计模式初探

回迁居住区是城市化推进的产物之一。回迁居民在这里的生活模式和物质环境都与其本来状态存在许多矛盾与冲突,使得回迁者常出现“回而不适”现象,对农民生活、心理产生极大负面影响。文章以哈尔滨市城郊失地失宅农民为研究对象,通过对哈尔滨市现有回迁居住区进行实地调研,总结出农民回迁者审美的特异性和行为活动需求及农民回迁居住区户外空间环境存在的主要问题,最后提出满足于哈尔滨失地失宅农民审美情趣及行为需求的农民回迁居住区户外空间设计策略,让农民回迁者有一定的家园感与归属感。     

Developing gene-tagged molecular markers for functional analysis of starch-synthesizing genes in rice (Oryza sativa L.)

The granule-bound starch synthase(GBSS), starch branching enzymes 1 (SBE1)and 3 (SBE3) are major enzymes involved in starch biosynthesis in rice endosperm. Available sequences of Sbe1 and Sbe3 genes encoding corresponding SBE1 and SBE3 have been used to identify homologous regions from genome databases of both the indica rice 93-11 and the japonica rice Nipponbare. Sequence diversities were exploited to develop gene-tagged markers to distinguish an indica allele from a japonica allele for both Sbe1 and Sbe3 loci. With these newly developed gene-tagged markers and available Wx gene markers, the roles of these starch-synthesizing genes (Sbe1, Sbe3, and Wx) in determining amylose content (AC) in the rice endosperm were evaluated using a double-haploid (DH)population derived from a cross between the indica rice cv. Nanjing11 and the japonica rice cv. Balilla. Only the Wx and Sbe3 loci had significant effects on the AC variation. On average, indica Wx ^a genotypes showed ∼9.1% higher AC than japonica Wx ^b genotypes, while indica Sbe3 ^a genotypes showed ∼1.0% lower AC than japonica Sbe3 ^b genotypes. A significant interaction was also observed between Wx and Sbe3 loci whereby the amylose content was 0.3% higher in Sbe3 ^a than Sbe3 ^b genotypes in the presence of the Wx ^a allele, but it was lower by 2.3% in the presence of the Wx ^b allele. Overall, polymorphisms at the Wx and Sbe3 loci together could account for 79.1% of the observed AC variation in the DH population. The use of gene-tagged markers in marker-assisted selection and gene functional analysis was also discussed. This revised version was published online in July 2006 with corrections to the Cover Date.