东亚飞蝗光谱特征波长筛选与龄期识别方法研究

利用高光谱图像采集系统在400~1 000 nm波段范围内采集东亚飞蝗成虫、5龄、4龄和3龄的前胸背甲光谱信息;每个龄期提取15像素×15像素目标区域平均反射率信息作为样本信息;提出了一种基于K均值聚类和主成分分析(K-PCA)相结合特征波段提取方法,对比分析K-PCA和SPA(投影连续变换)2种特征波长提取方法,采用Fisher判别分析方法分别对K-PCA和SPA筛选的特征波长建立东亚飞蝗龄期识别判别模型,实验结果表明K-PCA筛选出的特征波长数少且正确识别率为98.25%。K-PCA筛选的特征波长为468 nm、555 nm、635 nm、710 nm、729 nm、750 nm、786 nm和899 nm。本文提取的东亚飞蝗特征波长为东亚飞蝗的龄期识别奠定基础,进而对蝗灾的监测与预防提供了技术支持。     

冬枣果园土壤非交换态钾的释放动力学

为了研究长期施肥条件下冬枣果园土壤非交换态钾的释放特征,以Ca Cl2和柠檬酸溶液为浸提剂,采用连续提取的方法对枣园土壤的非交换态钾释放动力学进行研究。结果表明,枣园土壤非交换态钾在释放过程中表现出快速释放和缓慢释放2个连续的阶段。快速释放阶段(188 h)的累积释放量占到总释放量的53.6%~59.2%,而在缓慢释放阶段(188~1244 h)的释放量不及总量的一半。在相同时间内,使用柠檬酸溶液浸提时,非交换态钾的释放量明显高于使用Ca Cl2溶液时的释放量。相比之下,冬枣果园土壤非交换态钾的释放量明显高于对照土壤。在5种动力学方程中,幂函数方程是描述冬枣果园土壤非交换态钾释放的最优模型。     

南方红豆杉扦插繁殖技术研究

2003~2004年应用2年生南方红豆杉幼苗进行扦插试验研究,结果表明:不同时间扦插的插穗生根时间最多相差2个月,2月中旬至3月中旬为最适宜扦插季节,扦插后3~5个月的生根率高于其它月份。用河沙与红泥作基质扦插,在不同季节扦插中以河沙作基质的生根效果比红泥的好。用生根剂处理有利于插穗提早生根及增加生根数量,以冬季及早春应用的效果较为明显,应用生根剂的插穗在扦插3~5个月后的生根率和生根数量与对照比有显著差异。不同类型插穗的扦插生根率在不同月份扦插的结果不同,但其差异不显著。     

核桃叶片中氮、磷、钾含量及年动态变化规律研究

以早实核桃辽宁1号和晚实核桃礼品1号为例，分别测定早实核桃和晚实核桃叶片中不同生育期N、P、K的含量，结果表明，核桃叶片中N、P、K含量在幼龄叶中最高，整个生育期内核桃叶片中N、P、K含量总体上呈逐渐降低。早实核桃的N、P含量比同期的晚实核桃高，且差异极显著；而K含量无差异。     

山东百部离体快繁技术的研究

以山东百部(Stemona Shandongensis D.K.Zang)茎段为外植体,进行离体快繁技术的研究。实验结果表明:启动培养基为MS+6-BA 5.0mg.L-1+NAA0.1mg.L-1+糖30g.L-1+琼脂6.5g.L-1;分化培养基为MS+6-BA 4.0mg.L-1+NAA0.05mg.L-1+糖30g.L-1+琼脂6.5g.L-1;生根培养基为1/2MS+NAA0.1mg.L-1+糖30g.L-1+琼脂6.5g.L-1,通过正交试验也证明了实验结果。     

复合肥有机肥全量氮磷钾分析方法的探讨

采用水扬酸 -硫酸 -锌粉还原 ,双氧水作消化加速剂处理复合肥有机肥样品 ,测定N、P、K含量 ,结果与其它分析方法差异很小 ,回收率较高 ,是一种方便、快速测定复合肥、有机肥和其它肥料全量N、P、K的测试方法     

Forms and distribution of potassium in particle size fractions on talc overburden soils in Nigeria

The potassium status of soils developed over talc overburden in a southern Guinea savanna of Nigeria was evaluated using exchangeable, acid extractable, total and residual potassium values in particle-size fractions. Soil samples collected from genetic horizons of six profile pits at Kampe Forest Reserve were separated into sand, silt and clay fractions. Exchangeable K, acid-extractable K, total K and residual K were determined in these fractions. Reserved K values were similar to those of mobile K, but lower than total and residual K, whereas exchangeable K showed the lowest values. Total K was >25 cmol kg^?1 in all the profiles; reserved K ranged from 9.26 to 24.45 cmol kg^?1 and mobile K ranged from 5.12 to 29.57 cmol kg^?1. Exchangeable K accounted for <1% of total K and ranged from 0.20 to 0.50 cmol kg^?1. In most cases, the clay fraction of the soils had the highest values for all potassium forms, followed by the silt fraction, while the sand fraction had the lowest values for these forms of potassium.     

Effect of dimethylarsenic acid (DMAA) on growth,tissue arsenic,and photosynthesis of rice plants

The effect of dimethylarsenic acid (DMAA) applied to the root on arsenic (As) uptake and concentration, net photosynthesis (Pn), and growth parameters of rice (Oryza sativa L. cv. ‘Mercury') plants was studied. The experiment consisted of four treatments (0, 0.2, 0.8, and 1.6 mg As/L) with four replications in a completely randomized design. The DMAA was applied in nutrient solution as its sodium salt. The solution culture was changed every four days to avoid changes in the As chemical form. Arsenic uptake and concentration in shoot and root increased upon increased DMAA concentration in solution. Upon uptake, DMAA was readily translocated to the shoot. At the two higher rates of DMAA application (0.8 and 1.6 mg As/L), Pn and photosynthetic capacity were significantly decreased in response to tissue As concentration. Leaf area and dry matter production were also significantly reduced at the two higher rates of DMAA. At the lower rate (0.2 mg As/L) of DMAA application, there was no significant reduction in Pn or growth. Dimethylarsenic acid application did not affect nutrient allocation within the rice plant at concentration levels used in this study.     

Measuring interlayer potassium release rates from soil materials. II. A percolation procedure to study the influence of the variable ‘solute K’ in the < 1…10 μM range

Release rates of nonexchangeable K from Ap material of a Luvisol (‘Eckerde’ loess, 15% clay) are determined using a percolation procedure which avoids the common artifacts due to shaking or stirring soil suspensions and thus provides less biased kinetic data. CaCl₂ solution (10 mM_c. 20 °C. pH 5.8) is percolated through packages of soil aggregates (0.5–1 mm grain size, 0.5 g samples) with 0.02 to 25 ml h^?1. Solute K (C_K) was varied between < 1 and > 10 μM and is shown to have a dominant influence on the rates of interlayer K release. These increase exponentially below 3.5 μM (no steady state but steady decrease of release rates in each sample). The difference between the related C_K between moderate and high release rates is as small as 1 μM K. The average rates, of a 10-day-interval, starting after 1.3 times the exchangeable K had been removed, are 40 μmol K kg^?1 soil d^?1 at 4 μM C_K and 240 μmol kg^?1 d^?1 at 3 μM C_K, respectively. It is concluded that larger quantities of interlayer K become plant available in the studied soil if the of soil solutions gets below 3.5 μM (for 10 mM_c Ca, 20 °C, pH 5.8), probably because the dominant dioctahedral illites start to join the release process below this critical limit. The higher K concentration range was accounted for by K-Ca exchange isotherms which, by alteration of shape, indicate that K_nex release becomes measurable below 10 to 20 μM K. It is further argued that existing diffusion or reaction kinetics approaches towards K release are incomplete because the influence of solute K is not considered.     

Influence of soil ingestion by earthworms on the availability of potassium in soil: An incubation experiment

Summary An incubation experiment was conducted to study the changes that occur in the K status of soil due to earthworm activity. Samples of Tokomaru silt loam soil were inoculated with the common pasture earthworm species Aporrectodea caliginosa and incubated for 21 days. Aliquots of moist soil were analyzed for exchangeable K by leaching with neutral molar ammonium acetate at 1:50 soil solution ratio. Extraction with boiling 1 M nitric acid at 1:100 soil solution ratio for 20 min was used to determine available non-exchangeable K. The results indicated that the exchangeable K content increased significantly due to earthworm activity but nitric acid-extractable K did not change significantly. It is inferred that earthworms increase the availability of K by shifting the equilibrium among the forms of K from relatively un-available forms to more available forms in the soil chosen for the study.