采用Gompertz函数的水稻土压缩特性研究   总被引：4，自引：1，他引：3  

霍连飞  BelalEisaAdam  丁启朔  何瑞银  汪小旵 《农业工程学报》2020,36(12):136-142

土壤压实模型是预测压实破坏的常用方法,但土壤压实模型的应用常因输入参数(土壤压缩特性及其与不同土壤物理性质之间的关系)的缺乏而受到限制。为定量地评价土壤水力学性质和土壤结构对土壤压缩特性的影响,该文利用土壤固结仪对25种不同含水率和容重的重塑土样进行单轴压缩试验,并采用Gompertz函数对试验数据进行拟合以获取土样的回弹指数、压缩指数和先期固结压力。试验结果表明,Gompertz函数对水稻土试验数据的拟合效果较优,决定系数为0.991～0.999。水稻土回弹指数为0.003～0.138,与容重呈负相关,与含水率呈正相关。水稻土压缩指数为0.115～0.839,与容重呈负相关,与含水率呈二次多项式关系。水稻土先期固结压力为33～127k Pa,与容重呈正相关,与含水率呈负相关。该研究建立的土壤压缩特性与含水率和容重之间的传递函数,可用于大尺度范围内水稻土压缩特性的预测;同时这些传递函数可作为土壤压实模型的输入参数,用于农业机械作业引起的压实破坏的量化和土壤压实风险的评估。  相似文献   

The classification of varieties of the potato. — field demonstration     

Adam Millar 《American Journal of Potato Research》1924,1(12):286-287

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In situ weathering of rocks or aeolian silt deposition: key parameters for verifying parent material and pedogenesis in the Opawskie Mountains—a case study from SW Poland     

Loba  Aleksandra  Sykuła  Marcin  Kierczak  Jakub  Łabaz  Beata  Bogacz  Adam  Waroszewski  Jarosław 《Journal of Soils and Sediments》2020,20(1):435-451

Purpose

The aims: (1) to investigate the role of the in situ weathering of bedrock in providing substrate for soil formation; (2) to evaluate the aeolian contribution to the mountainous soils in the vicinity of thick loess cover; and (3) to determine the influence of aeolian silt on further soil development.

Materials and methods

The sampled sites were arranged along the slope toposequence, where an aeolian/silt admixture possibly occurred. Each soil catena started at the top of a hill and ended at its foot. Such an arrangement of the soil profiles ensured the tracking of loess thickness variations and detection of the depth of the residuum-derived materials. One reference soil profile, consisting of aeolian silt deposits, was made. The following soil properties were determined: pH, organic carbon content, soil texture, exchangeable acidity, exchangeable ions and geochemistry. In addition, thin sections were prepared from rock samples to confirm the type of bedrock present.

Results and discussion

The soils in the studied area were classified as Cambisols, Luvisols and Stagnosols, characterised by silt loam texture and a high content of elements indicating an aeolian silt contribution—Hf (7.4 to 14.8 ppm) and Zr (274.4 to 549.0 ppm). These values differ strongly from the residues typical of weathered quartzite, greywacke or catalasite substrates, which generally have low concentrations of Hf and Zr (0.7 to 7.0 ppm and 26.0 to 263 ppm, respectively). Based on the morphological, textural and geochemical data of the studied soils, three layers were distinguished, which show different inputs of aeolian silt: (1) an aeolian silt mantle; (2) a mixed zone in which loess was incorporated into the local material; and (3) a basal zone, free of the influence of aeolian silt. Based on the obtained results, a hypothetical pathway for soil formation in mountainous areas, influenced by aeolian silt admixing, was proposed.

Conclusions

Our study demonstrates that the soils developed in the Opawskie Mountains are characterised by an aeolian silt influence. This differentiates them from weakly developed soils, which comprise materials formed during in situ weathering only. Materials originating from bedrock weathering did not play an independent role as the parent material for the studied pedons. Aeolian silt was admixed with already existing autochthonous substrates, or completely replaced them. This influence on the soil formation resulted in the occurrence of Luvisols, Stagnosols and Cambisols. Such soils cannot be formed from the weathering of quartzites and greywackes, which contribute to a less structure-forming medium.

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Experiments to increase red grouse stocks and improve the Irish Bogland environment     

Adam Watson  P.J. O&#x;Hare 《Biological conservation》1973,5(1):41-44

Blanket bog in western Ireland is a wet infertile habitat, heavily grazed by sheep and cattle, and supporting very low densities of Red Grouse and other wild birds and mammals. An experiment using phosphatic fertilizers increased the growth of vegetation and the nutritive value of the Heather. There followed an increase in the population density of Grouse: territories became smaller and the Grouse reared bigger broods. An experiment in which sheep were excluded led to better growth of Heather and colonization by Grouse.  相似文献   

Heterogeneity and Collective Action: Community Integration Appraisal for REDD+ Forest Management Implementation     

Flanery  Adam  Mbatu  Richard  Johns  Rebecca  Stewart  Dona 《Small-Scale Forestry》2020,19(1):1-17

Small-scale Forestry - This study employs in-depth qualitative and quantitative research methods including survey and other ethnographic methods, concept mapping and informal qualitative...  相似文献   

A Rapid Protein Digestibility Assay for Identifying Highly Digestible Sorghum Lines     

Adam Aboubacar  John D. Axtell  Chia‐Ping Huang  Bruce R. Hamaker 《Cereal Chemistry》2001,78(2):160-165

Protein digestibility in sorghum (Sorghum bicolor (L.) Moench) lines was determined using two standard procedures (pepsin digestibility and pH‐stat) and compared with a newly developed, rapid electrophoresis‐based screening assay. The new assay was based on the rate of α‐kafirin disappearance after pepsin digestion. α‐Kafirin, the major sorghum storage protein, makes up ≈60–70% of the total protein in the grain. In the new assay, samples were first digested with pepsin for 1 hr, and undigested proteins were then analyzed by SDS‐PAGE. The intensitizes of the undigested α‐kafirin bands were measured. Higher band intensity indicated lower protein digestibility. The new assay was significantly correlated with the standard pepsin digestibility assay (r = −0.96, n = 16) after which it was patterned. The same was true of the pH‐stat procedure (r = −0.85, n = 16). This implies that the new assay is comparable to existing procedures and can be used for screening sorghum lines for protein digestibility. Two groups consisting of high‐protein digestibility and wild‐type sorghum lines were identified when the new assay was tested on 48 sorghum lines derived from crosses of wild‐type and mutant high protein digestibility lines, indicating that the new assay was efficient in differentiating between the two groups. Advantages of the new assay over the standard procedures include considerable reduction in analysis time and sample size required for the analysis. For example, analysis time was reduced by 20% and sample size by 10% when the new assay was used as compared with the pH‐stat procedure. We estimate that ≈60 sorghum lines can be screened in a day by a single operator using the new assay.  相似文献