生物炭对灌淤土氮素流失及水稻产量的影响

针对宁夏引黄灌区氮素流失严重的现状,通过大田试验研究生物炭施于灌淤土对水稻产量、水稻生育期内氮素运移特征及氮素流失量的影响。在常规施肥条件下设置高量炭(C3N300:9000 kg·hm-2);中量炭(C2N300:6750 kg·hm-2);低量炭(C1N300:4500 kg·hm-2)和不施炭(C0N300:0 kg·hm-2)4个处理。研究结果表明,生物炭和氮肥配合施用,对稻田田面水和渗漏水中氮素动态有一定影响,表现为总氮(TN)和硝态氮(NO-3-N)浓度随生物炭用量增加而降低,铵态氮(NH+4-N)浓度升高;在对各层土壤氮素动态的影响上,表现为20 cm处渗漏水中氮素浓度受生物炭用量影响明显,但100 cm处氮素浓度受影响较小。对水稻生育期内氮素径流损失的影响表现为随生物炭施用量增加,田面水TN和NO-3-N径流流失风险下降,但NH+4-N径流流失风险增加;本研究条件下添加生物炭对NO-3-N和NH+4-N淋失没有表现出影响,TN淋失表现为随生物炭用量增加而降低,其中TN淋失量最小的是C3N300处理,整个生育期内淋失量为26.28 kg·hm-2,与常规施肥处理C0N300相比,减少9.45%。另外,添加生物炭增加水稻穗粒数和穗数,使水稻理论产量显著增加15.3%~44.9%,其中C3N300产量显著高于其他处理(P0.05)。生物炭用于灌淤土对水稻产量有促进作用,对降低稻田氮素淋失也表现出积极效果。     

牛粪源和木源生物炭对Pb（Ⅱ）和Cd（Ⅱ）的吸附机理研究

在700℃热解条件下制得牛粪源生物炭(DMBC)和木源生物炭(WC)。研究了二者对水体中Pb(Ⅱ)和Cd(Ⅱ)的吸附去除能力,分析了相关污染物去除机理。结果表明:DMBC的比表面积和碳元素含量均远小于WC,但去除效率却远高于后者。FTIR光谱分析和XRD分析表明,DMBC中含有大量矿物组分(如磷等),易与重金属离子生成沉淀。因此在吸附去除过程中发挥主导作用的是沉淀机制。Pb(Ⅱ)和Cd(Ⅱ)在DMBC上的竞争吸附和单组分吸附结果类似,验证了该结论的正确性。而Pb(Ⅱ)和Cd(Ⅱ)在WC上的单组分和双组分吸附结果相差较大,这说明重金属离子在WC上的吸附是以表面吸附为主。以上研究证实,牛粪源生物炭比木源生物炭更适合用于水体中各类重金属污染的去除。     

The influence of feeding history on the acute stress response of common carp (Cyprinus carpio)

The effect of an 80-day maintenance-feeding period on the acute stress response of common carp, Cyprinus carpio, to net confinement was determined. Fish were raised on an optimal feeding level of 20 g food/kg of metabolic fish weight per day (g/kg^0.8 day⁻¹) until 124 days post-hatch (dph). Feeding in group one (L>H) was then reduced to maintenance levels, i.e. 5 g/kg^0.8 day⁻¹ until 204 dph, when the feeding was again increased to 20 g/kg^0.8 day⁻¹. In group two (H>L), the feeding level was reduced from 20 to 5 g/kg^0.8 day⁻¹ on day 146. All fish were sampled at 226 dph. Food ration had significant effects on the growth rate and food conversion values with fish fed the high ration performing better than those on a lower level. Prior to the application of the stressor, only plasma levels of triglycerides were lower in fish fed a low food ration (H>L). Feeding history influenced the onset of the stress response with stressor-induced elevations of plasma cortisol, glucose and free fatty acids being higher in fish fed a high ration compared with those fed a low ration prior to sampling. These results suggest that feeding history through modification of the energy reserves can influence the onset of the acute stress response.     

钙镁型秸秆生物炭肥缓释性能及其对玉米生长的影响

化肥的一次施用量过大造成面源污染,给生态环境带来了诸多负面影响,功能化生物炭是构建化肥缓释的重要材料,是生物炭基缓释肥开发的一条途径。该研究以玉米秸秆为炭原料,鸡蛋壳为钙原料,基于热解转化技术耦合氮磷的同步富集制备钙镁型秸秆生物炭肥(Ca/Mg-BCF)。通过温度和pH值对Ca/Mg-BCF缓释性能的影响试验、缓释动力学和淋溶模拟试验等,研究了Ca/Mg-BCF的缓释性能;结合表征技术,初步揭示其缓释氮磷的机理;利用盆栽试验考察了该炭肥与传统化肥对玉米生长影响。结果表明:Ca/Mg-BCF对N和P的缓释作用明显优于化肥(CF),Ca/Mg-BCF对N和P的释放率(5.90%和8.68%)在缓释48 h后,分别比CF降低了88.10个百分点和74.22个百分点;淋溶试验证明,Ca/Mg-BCF对N和P的累积释放率呈现缓慢增长的趋势;Ca/Mg-BCF对养分的释放受温度(10～40℃)的影响较小,其对N和P的释放分别在pH值为1～7和3～10之间较为平稳。Ca/Mg-BCF对N和P的缓释性能,主要受多种作用协同控制,包括鸟粪石等晶体的溶解速率、磷酸根的再沉淀、静电吸引以及生物炭的限域效应等...     

Effect of Different Dietary Nutrition Levels on Fattening Effect of Holstein Bulls

This experiment was conducted to study the effect of different dietary nutrition levels on fattening effect of Holstein bulls.48 4-month-old Holstein bulls with an average body weight of 128 kg were allocated into two groups,group Ⅰ was fed a low nutrition level diet,group Ⅱ was fed a high nutrition level diet.Each group had 24 Holstein bulls.The pre-test period lasted for 7 days and the trial period lasted for 245 days.The results showed that compared with group Ⅰ,the ADG in group Ⅱ was significantly increased by 6.36% (P<0.01),while the F/G in group Ⅱ was decreased by 6.55%.With the increasing of dietary nutrition levels,the apparent digestibility of CP,EE,NDF,ADF,Ca and P were rising,but there was no significant differences between two groups (P>0.05).Compared with group Ⅰ,the serum GLU,AST,ALT and GH contents in group Ⅱ were increased by 12.52%,12.85%,9.68% and 13.24% (P<0.05),respectively,while the serum BUN content in group Ⅱ was decreased by 10.98% (P<0.05).Compared with group Ⅰ,the feeding profits of group Ⅱ increased by 1.37 yuan/(head·day),the total economic benefit of group Ⅱ increased by 335.65 yuan/head.In conclusion,the improvement of dietary nutrition levels could improve the fattening performance and the economic benefit of Holstein bulls.     

育成期雄性幼貉日粮适宜蛋白质和能量水平的研究

选用健康乌苏里幼公貉63只,随机分为7组(每组9只)。1～4组用以探讨适宜蛋白质水平,其蛋白质水平分别为31.54%、36.39%,40.37%和43.53%;5-7组用以探讨适宜能量水平,其能量水平分别为19589.78,21860.94和22600.04k J/kg。试验分育成前期和冬毛生长期两个阶段进行,饲喂同一营养水平的日粮。结果表明,育成前期饲喂蛋白质水平为36.39%的日粮,可获得理想的体重、体长及经济效益。 冬毛生长期,日粮蛋白质水平在31.54%～43.53%范围内,对幼貉的体重和体长无显著影响。育成期以饲喂能量水平为21860.94～22600.04 k J/kg的日粮为宜。育成前期适宜的蛋能比为16.1～16.6,冬毛生长期为14.0～14.4。     

Does Biochar Improve Establishment of Tree Seedlings in Saline Sodic Soils?

Reforestation of saline sodic soil is increasingly undertaken as a means of reclaiming otherwise unproductive agricultural land. Currently, restoration of degraded land is limited to species with high tolerances of salinity. Biochar application has the potential to improve physical, biological and chemical properties of these soils to allow establishment of a wider range of plants. In a glasshouse trial, we applied biochar made from Acacia pycnantha (5 Mg ha⁻¹) or no biochar to either a low (EC_e 4·75 dS m⁻¹, ESP 6·9), a moderate (EC_e 27·6 dS m⁻¹, ESP 29·3) or a high (EC_e 49·4 dS m⁻¹, ESP 45·1) saline sodic soil. The regional common reforestation species Eucalyptus viminalis and Acacia mearnsii were planted as tubestock in to the soils. Early establishment indicators, including growth, plant condition and nutrition, were assessed at the end of a simulated growing season, 108 days after biochar application. Application of biochar increased height, and decreased root : shoot and the concentration of Mn, N and S in plants of E. viminalis when grown in the highly saline sodic soil. Biochar application increased the concentration of B in leaves of E. viminalis and increased the concentration of P, K and S in leaves of A. mearnsii when grown in the low saline sodic soil. The results confirm that there is potential for biochar to assist in reforestation of saline sodic soils. Copyright © 2015 John Wiley & Sons, Ltd.     

The genomes of Arachis hypogaea 2. The implications in interspecific breeding

Summary The existence of structural differentiation between genomes in section Arachis of the genus Arachis has important implications in the utilization of diploid wild species in this section as a germplasm resource. Maximum expression of desirable characters may not be achieved unless tetrasomic dose levels can be achieved. Possible breeding strategies discussed include natural and induced gene exchange between genomes and chromosome substitution which could be brought about by manipulation of ploidy level and where appropriate the use of ionizing radiation. Such strategies could be tested in the improvement of resistance to the Cercospora leafspots.Paper number 5561 of the Journal Series of the North Carolina Agricultural Experimental Station, Raleigh, NC 27650.     

Comparison of some selection procedures and objectives in faba beans (Vicia faba L.). I. direct and index selection for seed yield

Summary Starting with two heterogeneous F₂ populations, each based on 20 cross combinations, different selection procedures were applied for four consecutive selection cycles. Three of the selection procedures involved seed yield per plant (SYP): (i) direct selection for SYP (DSY); (ii) indexselection for SYP (ISY) with plant length, the ratio of the vegetative top to plant length, end of grain filling and duration of the generative stage as auxiliary characters and finally; (iii) independent culling levels selection (ICL) for the index described above and crude protein content. For ICL-selection the attention is focussed on SYP in this paper.For all three selection procedures, predicted and realized responses were calculated and expressed as percentage of a corresponding non-selected population. The intensities of selection differed over selection methods and generations, mostly due to practical constraints.As far as predicted responses are concerned, ISY-selection seemed to be slightly superior to DSY-selection and DSY-selection to ICL-selection. This order may partly be due to differences in selection intensity. However, none of the predictions was very accurate, but the predictions of ICL-selection seemed to be the most accurate. This has been ascribed also to the relative mild selection intensity applied in ICL-selection. It is concluded that a decision in favour of a complicated selection procedure like index selection based on predicted responses only cannot be defended. As far as realized responses are concerned, DSY-selection seems to be slightly superior to the other two selection procedures, as it is the only procedure that resulted in a more or less stable positive response to selection.The auxiliary characters, especially plant length, showed a marked correlated response to all three selection procedures. In case of direct selection for SYP this seemed paradoxical with the inefficiency of index selection, but, it may reflect the differences in the genuine genotypic correlations and the estimated genotypic correlations.     

不同施氮水平下棉花生物量动态增长特征研究

在大田实验条件下,以定量方法系统地分析了黄淮海棉区(以河南安阳为试点)不同施氮水平(每公顷0 kg、120 kg、240 kg3、60 kg、480 kg)下棉株生物量的动态累积特征,结果表明:棉株地上、地下部分干物重的动态累积符合Logistic生长曲线,生物量的增长对氮肥施用量较为敏感;施肥量为360 kg.hm-2时棉田具有快速增长期启动早、持续时间短、增长速率大等特征,说明该施氮量利于棉花生长前期的生物量的快速累积,氮肥施用量过多或过少均不利于合理棉花群体的建立;不同的施氮量可以调节快速生长期的早晚和持续时间,同时亦可改变其干物质累积速率。生产中可以通过调节氮肥的施用量与时间获得高产。对于黄淮海棉区,适宜的施肥量为360 kg.hm-2,7月中旬为棉田肥水管理的关键期。