Effects of phosphate fertilizer levels on cowpea pod-sucking bug populations and damage

The effect of different application levels of phosphate fertilizer on cowpea pod-sucking bugs [Clavigralla sp., Riptortus sp., Anoplocnemis., Mirperus sp. and Negara sp. (Heteroptera)] was studied using 0 (control), 20, 40 and 60 kg/ha of single super-phosphate. The results showed that the bug densities decreased significantly with increase in rate of application. At 40 and 60 kg/ha, grain yields were significantly higher than at the lower rates of application. Crude protein, fibre, oxalate, phytin, potassium and magnesium contents as well as seed hardness also increased with increase in the rate of fertilizer application.     

用双磷酸淀粉增强牛皮箱板纸强度的试验

在牛皮箱板纸的面浆中添加少量的双磷酸淀粉，具有较好的增强效果，如与化学合成助剂配合使用，其效果更为明显．此方案是一条增强纸板强度、投资少、见效快的有效途径．     

中国莲PHT1家族成员的生物信息学分析

以植物PHT1家族蛋白为研究对象,基于中国莲(Nelumbo nucifera)全基因组数据库,利用生物信息学方法发掘中国莲可能存在的PHT1家族成员,并对中国莲PHT1家族成员进行序列比对、系统进化、保守序列、跨膜结构、二级结构和亚细胞定位等分析。结果表明,从中国莲全基因组数据库中筛选获得4个PHT1蛋白,分别命名为:Nn PHT1:1、NnPHT1:2、NnPHT1:3、NnPHT1:4。它们在植物PHT1家族中属于GroupⅠ,均含有保守序列:GGDYPLSATIxSE。该序列具有11~12个跨膜区域,且保守序列位于第4个跨膜区域内,均定位于细胞质膜,且在细胞内侧第6和第7个跨膜区域之间均含有一个较大的细胞胞质内环结构;磷酸化位点和糖基化位点的数量范围分别在33~50个和4~9个;二级结构中α-螺旋和无规卷曲结构的数量总和均高于70%。研究结果展示了中国莲的PHT1家族成员的序列基本信息和结构特点,为深入研究中国莲的该家族成员基因及其编码蛋白的结构功能提供理论依据。     

不同磷肥用量及施用方式对土壤有效磷分布和冬小麦产量的影响

为了最大程度提高磷肥的增产潜力,实现冀中南施肥减量增效,通过田间试验和室内检测的方法,研究了以固体磷肥全部底施为对照,不同施磷处理对土壤有效磷分布和冬小麦产量及产量因素的影响。结果表明：（1）与习惯施磷肥方式相比,水肥一体化喷施液磷肥可使20~60 cm土层有效磷含量提高明显;（2）减少基施固体磷肥,改为春季水肥一体化喷施液态磷肥,可增加穗粒数和千粒重,提高冬小麦产量;（3）磷肥施用宜底施固体(P₂O₅) 90 kg/hm²的基础上,春季喷施液态(P₂O₅) 30 kg/hm²小麦产量效果为佳。底施固体磷肥,并在春季分2次平均水肥一体化追施液体磷肥,可实现磷肥施用“下移增效”。     

根际耐盐真菌分离筛选及溶磷促生性能分析

溶磷微生物可提高土壤中有效磷含量,但目前筛选的溶磷菌株在盐渍化土壤中应用的潜力有限。以滨海盐生植物根际土壤为材料,分离筛选可用于盐碱土改良的高效耐盐解磷菌株,为盐碱土生物菌肥的研制提供优质菌种资源。结果表明,北戴河湿地及曹妃甸湿地的3种原生盐地植物根际土壤中共分离筛选无机磷降解菌株5株和有机磷降解菌株3株,命名为C1-C7和G1,均能耐受10%的盐浓度。菌株间解磷能力差异显著,D/d为1.05~1.81,无机磷降解菌解磷量为26.61~4415.00mg/L,与对照相比有效磷增量为0.80~4371.10mg/L;有机磷降解菌解磷量为1.96~5.79mg/L,有效磷增量-3.40~0.20mg/L,有效磷含量与D/d之间相关性不强。其中菌株C1降解无机磷能力最强,溶磷量达4397.70mg/L,吲哚乙酸（IAA）分泌量为33.07mg/L,经分子鉴定该菌株为草酸青霉,是一株高效耐盐解磷菌,兼具促生作用,可以考虑作为盐碱地改良菌肥的重点菌种,与植物协同改良修复中重度盐碱土,可有效提高盐碱地土壤肥力,有更好的应用潜力。     

Soil properties related to phosphate buffering in calcareous soils

Abstract

In a group of 24 related calcareous soils, derived from Jurassic oolitic limestone, there was marked variability (13‐fold) in phosphate buffering when expressed as the maximum buffer capacity. This variability was most closely related to the iron content and pH of the soils, and these together accounted for 72% of the variance. This percentage was not increased by including CaC0₃ content or organic matter, which were also correlated with the maximum buffer capacity. A high correlation with specific surface area of CaCO₃ was probably an indirect effect due to the high correlation between this variable and the Fe and pH of the soils.

The equilibrium buffer capacity, which is the traditional measure of phosphate buffering, was less variable but quite unrelated to all the soil properties measured except the soil surface area. However the maximum buffer capacity and quantity of adsorbed P together accounted for 63% of the variance in this parameter.     

抚仙湖代村河流域磷矿开采迹地磷入湖负荷量调查研究

[目的]为了研究抚仙湖流域废弃磷矿区通过地表径流输移进入湖泊的磷污染负荷量。[方法]对废弃磷矿所处的代村河小流域布设监控点,进行废弃磷矿来源污染物通量周年观测和降雨径流过程加密观测,建立了代村河小流域磷矿污染物流失量、地表径流量与日降雨量关系式。[结果]估算得到磷矿废弃地产生的污染物通过代村河小流域输移总磷和磷酸盐分别为5.6和3.47 t/a;周年观测结果表明废弃磷矿产生的污染物主要通过降雨淋溶形成的地表径流向外界传输,降雨期间入湖河流水质TP浓度是非雨期间的20～80倍。[结论]废弃磷矿流失的磷是抚仙湖持久性磷污染源,必须对废弃磷矿开采区实施生态修复,减少磷释放及入湖负荷量,遏制湖泊富营养化进程。     

抚仙湖磷矿开采区入湖河流末端湿地净化效果研究

[目的]研究抚仙湖磷矿开采区入湖河流末端湿地的净化效果。[方法]对东大河河口湿地系统运行参数进行了一周年的测试,分析该湿地系统对磷矿来源污水的净化效果。[结果]湿地对TN、TP、CODCr入湖污染负荷量的平均去除率分别为52%、32%、54%,设计水力负荷为0.67 m3/(m2.d)时处理效果最好。工程已稳定运行6年,达到无能耗、防堵塞、高去除率的运行效果。[结论]该湿地有效削减了磷矿开采产生的入湖污染物负荷量,对保护抚仙湖起到关键的作用。     

一株溶磷细菌的分离、鉴定及其溶磷特性研究

从作物根际土壤样品中筛选到一株溶 P 能力强的菌株 GJT-1,结合生理生化指标和16S rDNA 序列分析鉴定其为假单胞菌(Pseudomonas sp.).菌株 GJT-1 对磷酸三钙、磷酸铝、磷酸铁有一定的溶解能力,28℃培养到第 3 天对磷酸三钙液体培养基的溶 P 量可达 224.51 mg/L.该菌对开阳磷矿粉和宜昌磷矿粉的溶 P 量分别为 194.25 mg/L 和 120.59 mg/L.通过扫描电镜观察到接种活菌处理的磷矿粉表面凹凸且有黏性物质附着,表明菌株 GJT-1 可利用磷矿粉.     

Crop residue contributions to phosphorus pools in agricultural soils: A review

The phosphorus (P) content of crop residues and its availability to a subsequent crop can range from agronomically insignificant, to quantities in excess of crop P requirement. However, the contribution of crop residues to the P nutrition of subsequent crops has not been widely recognised, and simple predictive tools are lacking. By reviewing the published literature in which quantitative measurements of P transformations from plant residues applied to soil have been reported, we have evaluated the contribution of crop residue-derived P to the P nutrition of subsequent crops, assessed the key factors involved and summarised the knowledge as an empirical model. The contribution of crop residues to P availability is likely to be significant only under conditions where large amounts of crop residues of relatively high P concentration are applied to soil. Crop residues with low P concentration, such as cereal stubble (eg. due to re-translocation of a large proportion of stubble P into grain), will not make an agronomically significant contribution to soil P availability, but may reduce P availability due to assimilation in the microbial biomass. However, a productive green manure crop may release sufficient P to meet the requirements of a subsequent cash crop. The release of P from crop residues is significantly reduced in systems where the P-status of crops and soils is low, which reinforces the reliance on external P inputs for sustained crop productivity. The large variability in the potential contributions of plant residues to the P nutrition of subsequent crops suggests that there is a strong need to integrate model predictions of organically-cycled P with fertiliser management strategies.