Leaching of heavy metals from sewage sludge through coastal plain soils

Abstract

Three types of sewage sludge are applied to the surface of soil columns of Coastal Plain soils and leached with distilled water. The Zn concentrations in leachate samples from a Sassafras loamy sand soil loaded with an industrial sludge increased with sludge loading rate. All leachate samples contained very low concentrations of Cd, Cr and Cu. Hazardous amounts of Cd, Cr, Cu and Zn would not be leached to the groundwater when recommended rates of the tested sludges are applied to Coastal Plain soils under most conditions.     

喷施硼、钼、锌对紫花苜蓿种子产量的影响

通过对盛花期紫花苜蓿(Medicago sativa)进行叶面喷施不同质量分数的硼、钼、锌，测定不同处理下紫花苜蓿种子产量、株高、千粒重、花序数/生殖枝、豆荚数/花序、籽粒数/豆荚等产量构成因素。结果表明，硼、钼、锌对紫花苜蓿种子产量及其构成因素有显著效应。3种微肥中0.9%硼、0.04%钼和0.6%锌处理对苜蓿种子具有良好的增产效果，种子产量分别比对照增加6.89%、26.51%和13.8%，其中0.04%钼增产效果最优。同时各处理对花序数/生殖枝、荚果数/花序、籽粒数/荚果等均有一定影响。     

甘蔗新品种“海大28号”的选育及其繁殖推广

甘蔗新品种“海大28号”是广东海洋大学农业生物技术研究所甘蔗研究室从母本为Co419、父本为Cp49／50的杂交种子播种育苗，按甘蔗育种程序逐级试验筛选获得的优良单系90／158，经采用^60Coγ射线对90／158单系梢部苗的单芽和茎梢幼嫩组织诱导的愈伤组织进行辐射处理改良而育成甘蔗新品种。多年试验结果表明，该品种具有高产、高纤维分、高糖、耐旱、抗虫、抗寒的糖能兼用的甘蔗新品种，适合广东、广西、云南、海南等蔗区地力中等或中等以上的旱坡地及水旱田推广种植。     

萝卜新品种秋白65的选育

秋白65是以不育系10A为母本，异型保持系R9711为第一父本，自交系H625为第二父本配制而成的萝卜三交种。生育期65 d（天）左右。植株生长势强。肉质根长圆柱形，长30～40 cm，横径6～8 cm，单根质量1.0～1.5 kg。外皮白色，光泽度好，商品性优。肉质脆甜，品质优。对病毒病和黑腐病的抗性强于对照丰玉一代，每667 m²产量4 000 kg以上，适宜秋季栽培。     

白浆土磷锌关系的研究

通过磷锌不同用量的室内培养试验和温室盆栽试验研究表明，大量施用磷肥降低了土的有效性，尤其是在缺锌的土壤中，白浆土锌分级测定表明，土壤中锌主要以矿物态存在，施用锌肥增加了交换态锌和氧化锰结合态锌含量；但同时施用磷肥，无定形铁结合态锌和晶形铁结合态锌则有一定的增咖，降低了土壤锌的有效性。施用磷肥也增加了锌在植株根部的积累，降低了植株根部的积累，降低了植株各上部锌供应。磷锌交互作用不仅发生在土壤中，也存     

Zn~(2+)胁迫对小麦幼苗生理活性影响的研究

以郑州9023为供试材料，采用室内水培方法，研究了不同浓度Zn^2＋（0、30、60、120、240、360mg·L^-1）对小麦幼苗生理活性的影响，初步阐明了Zn^2＋对小麦幼苗的毒害机理。结果表明，在Zn^2＋胁迫下，随处理浓度的升高，小麦幼苗叶片中超氧阴离子自由基（O2^-1）含量、丙二醛（MDA）含量、可溶性糖含量、抗坏血酸过氧化物酶（APX）及过氧化物酶（POD）活性均呈上升趋势，超氧化物歧化酶（SOD）活性呈先下降后上升的趋势；抗坏血酸（ASA）含量、过氧化氢酶（CAT）活性均呈现先上升后下降的趋势，可溶性蛋白和叶绿素含量呈下降趋势。对SOD、POD、CAT同工酶的聚丙烯酰胺凝胶电泳结果分析表明，正常情况下，小麦幼苗叶片主要表达Rf值（相对迁移率）分别为0．98、0．96、090．8、0．6、0．48的6条SOD同工酶带；POD同工酶带主要分为5区，至少包括10条同工酶酶带；CAT主要表达2条同工酶带。浓度小于120mg·L^-1的Zn^2＋抑制SOD同工酶的表达，促进CAT同工酶的表达，浓度大于240mg·L^-1的Zn^2＋促进SOD同工酶的表达，抑制CAT同工酶的表达，Zn^2＋诱导小麦幼苗中POD同工酶的表达。Zn^2＋没有诱导新的CAT、SOD和POD同工酶的表达。     

棉秆生物炭去除水中Zn(Ⅱ)的试验研究

为探究棉秆生物炭(棉秆炭)对重金属Zn(Ⅱ)的去除作用,利用水平管式炉分别在400℃、500℃、600℃热解温度下制备棉秆炭,进行Zn(Ⅱ)的吸附试验。对比棉秆炭、木质和煤质活性炭对不同浓度溶液中Zn(Ⅱ)的去除效果。分析棉秆炭的元素含量和官能团变化等性质,以揭示吸附机理。结果表明,棉秆的DTG曲线在327℃出现最大值,温度高于600℃时,DTG曲线趋于稳定,棉秆的热解基本完成。随热解温度的升高,炭产率、H/C和O/C元素比均下降,说明棉秆炭芳香化程度和碱性增强,含氧极性官能团数量减少,红外分析印证了以上结论。去除率上,棉秆炭与Zn(Ⅱ)初始浓度和热解温度负相关,木质活性炭与Zn(Ⅱ)初始浓度正相关;吸附量上,棉秆炭、木质和煤质活性炭与Zn(Ⅱ)初始浓度正相关,棉秆炭与热解温度负相关。当Zn(Ⅱ)溶液浓度为2 mg/L时,棉秆炭的吸附性能优于木质和煤质活性炭,当Zn(Ⅱ)溶液浓度为10 mg/L、50 mg/L时,木质活性炭的吸附性能优于棉秆炭和煤质活性炭。棉秆炭吸附Zn(Ⅱ)的机理包含配位反应和离子交换。     

氮锌配施对不同冬小麦品种产量及锌营养的影响

为比较石灰性土壤氮锌配施对不同小麦品种生长及锌营养的影响,选10种本地主要种植小麦品种,进行连续两年的田间试验,测定小麦产量及锌含量。结果表明,在石灰性土壤上单施锌肥和氮锌配施对小麦产量、籽粒锌含量的影响因品种而异。单施锌肥及氮锌配施处理可显著增加土壤有效锌含量,但单施锌肥处理仅增加"西杂1号"、"武农148"、"郑麦9023"籽粒锌含量;氮锌配施增加除"小偃22"外其余9种供试小麦品种籽粒锌含量,增幅为7.3%～54.7%。单施锌肥对小麦锌累积量增加的效果不明显;氮锌配施可显著增加小麦地上部锌累积量,两季分别增加6.5%、29.8%。单施氮肥可显著增加小麦锌吸收,但其主要累积在小麦茎叶部。在石灰性土壤上,单施锌肥虽显著增加了土壤有效锌含量,但对小麦产量及籽粒Zn含量增加有限,氮锌肥配施可取得较好效果。     

Comparative efficacy of ZnSO4 and Zn-EDTA application for fertilization of rice ( Oryza sativa L.)

Widespread Zn deficiency for rice crop has been reported from different parts of the world, including India. To correct such deficiency, Zn is often applied to the soil as fertilizer. Its concentration in soil solution and its availability to crops is controlled by sorption?–?desorption reactions at the surfaces of soil colloidal materials. The objective of this study was to compare the availability and relative effectiveness of Zn from Zn-EDTA and ZnSO₄ sources by applying different Zn levels to a calcareous soil in field experiments through soil application. The uses of Zn-EDTA also increase the yield of rice dry matter yield and grain yield. Regarding maintenance of Zn in soil, it has been observed that the amount of Zn content was recorded higher with the split application of Zn-EDTA as compared to ZnSO₄ with the simultaneous 26.1% increase in the yield of rice.     

Zinc and amino acids on wheat-soybean intercropping under no-till management

Abstract

Foliar fertilization with micronutrients and amino acids (AAs) has been used to increase the grain yield and quality of different crops. The aim of the present study was to evaluate the effects of Zn and AAs foliar application on physiological parameters, nutritional status, yield components and grain yield of wheat-soybean intercropping under a no-till management. We used a randomized block experimental design consisting of eight treatments and four replicates. The treatments were five Zn rates (0, 1, 2, 4 and 8?kg ha^?1) and 2?L ha^?1 of AAs and three additional treatments: a control (without the Zn or AA application), 2?kg ha^?1 Zn and 2?kg ha^?1 Zn + 1?L AA. The treatments were applied by spraying during the final elongation stage and at the beginning of pre-earing for the wheat and in growth stage V6 for the soybean for two crop years in a Typic Oxisol (860?g kg^?1 clay). Zinc foliar fertilization increased the wheat grain Zn concentrations. The Zn rates and AA foliar fertilization in soil with did not affect the physiological parameters, nutrient status or yield components. The AA application at the different concentrations tested changed the soybean grain yield and the leaf N concentration. The results suggest that Zn and amino acids application increases the grains Zn concentration in the wheat, being an important strategy to agronomic biofortification.