高光谱成像技术检测高温障碍胁迫下番茄叶片色差的研究

提出了利用可见/近红外高光谱成像技术检测高温障碍胁迫下番茄叶片色差的方法。首先采集380~1 023nm波段范围内60个高温障碍胁迫和60个健康番茄叶片的高光谱图像,同时获取全部叶片的色差值（L＊,a＊和b＊）,然后提取所有样本的高光谱图像中感兴趣区域（region of interest,ROI）的光谱反射率值。基于不同预处理方法建立偏最小二乘（partial least squares,PLS）预测模型,再利用连续投影算法（successive projections algorithm,SPA）提取特征波长并建立SPA-PLS预测模型。最后分别基于全波段和特征波段建立偏最小二乘-判别分析（partial least squares-discriminant analysis,PLS-DA）模型。结果显示,全波段中基于原始光谱信息建立的模型效果最好,3个色差值的预测集决定系数（determination coefficient,R2）分别是0.818,0.109和0.896;基于特征波长建立的模型预测集R2分别是0.591,0.244和0.673;所有模型预测集的总体识别率均大于77.50%。结果表明,可见/近红外高光谱成像技术检测番茄叶片色差值（L＊和b＊）和识别高温障碍样本是可行的。

Recovery of Essential Plant Nutrients from Biofuel Residual

Essential plant nutrients contained in residues and wastes generated during biofuel processing can be recovered for further production of bioenergy biomass. The objective of this study was to determine the relative agronomic efficiency of “processed” biofuel residual (PBR). Liquid biofuel residual was “processed” by precipitating phosphate and ammonium in the residual with magnesium into a struvite-like material. Then, in a series of greenhouse experiments, we evaluated the fertility potential of PBR, using sweet sorghum (Sorghum bicolor (L.) Moench), as a test bioenergy crop. We compared the agronomic effectiveness of PBR to inorganic commercial fertilizers, biosolids, and poultry manure as nutrient sources. The sources were either applied alone or in combination with supplemental essential plant nutrients (S, K, Mg, and micronutrients). In each of the greenhouse experiments, the crop was grown for 12 wk on soil of minimal native fertility. After each harvest, sufficient water was applied to the soil in each pot over a 6-wk period to yield ~2 L (~one pore volume) of leachate to assess potential total N and soluble reactive phosphorus (SRP) losses. Dry matter yields from the PBR treatment applied alone were significantly greater than yields from inorganic fertilizers, biosolids, and poultry manure treatments applied alone, and similar to yields obtained when the supplemental essential plant nutrients were added to the inorganic fertilizer, biosolids, and manure treatments. Leachate N and SRP concentrations from the PBR treatment were significantly lower than in the treatments with inorganic fertilizers, poultry manure, and biosolids. We conclude that PBR can substitute for inorganic fertilizers and other organic sources of plant nutrients to produce bioenergy biomass cheaply, without causing offsite N and P losses in vulnerable soils.

An in-situ Technique for Producing Low-Cost Agricultural Biochar

Application of biochar to agricultural soils is effective to sequester atmospheric carbon and improve soil quality, but current pyrolysis and transportation costs are high, making biochar too costly to be used at the field scale. This study developed a new in-situ technique, burning and soil covering(B-SC), which can be used by farmers for production of biochar with crop residue. In this study,the air-dried feedstocks, elephant grass and corn residue, were burnt in situ for biochar production in the field. After approximately 90% of the leaves were combusted, the burning process was dramatically slowed down by covering the feedstock with soil. The biochar yield averaged 18.0 ± 1.3(n = 15) and 13.7 ± 1.3(n = 10) kg per 100 kg air-dried feedstock for the elephant grass and corn residue,respectively. The biochar properties were suitable for soil improvement. The inputs for biochar production of the B-SC process only included low labor force, open field, feedstock(e.g., grass and crop residue), and simple tools. The operation time for processing 10 kg of the corn residue by an individual farmer was 24.4 ± 4.1 min(n = 10). As compared with the conventional field burning process, the B-SC process drastically shortened the time for biomass burning and generated a significantly lower emission of smoke and thermal energy. This simple technique can be particularly practical and effective for farmers to improve the soils of poor quality in China.

Development of yield forecast model using multiple regression analysis and impact of climatic parameters on spring wheat

Understanding the impacts of climate change in agriculture is important to ensure optimal and continuous crop production.The agricultural sector plays a significant role in the economy of Upper Midwestern states in the USA,especially that of North Dakota(ND).Spring wheat contributes most of the wheat production in ND,which is a major producer of wheat in the USA.This study focuses on assessing possible impacts of three climate variables on spring wheat yield in ND by building a regression model.Eighty-five years of field data were collected and the trend of average minimum temperature along with average maximum temperature,average precipitation,and spring wheat yield was analyzed using Mann-Kendall test.The study area was divided into 9 divisions based on physical locations.The minimum temperature plays an important role in the region as it impacts the physiological development of the crops.Increasing trend was noticed for 6 divisions for average minimum temperature and average precipitation during growing season.Northeast and Southeast division showed the strongest increasing trend for average minimum temperature and average precipitation,respectively.East-central division had the most decreasing trend for average maximum temperature.A significant relationship was established between spring wheat yield and climatic parameters as the p-value is lower than 0.05 level which rejects the null hypothesis.The regression model was tested for forecasting accuracy.The percentage deviation of error for the model is approximately±30%in most of the years.

Transferability and Scalability of Soil Total Carbon Prediction Models in Florida, USA

The applicability, transferability, and scalability of visible/near-infrared(VNIR)-derived soil total carbon(TC) models are still poorly understood. The objectives of this study were to: i) compare models of three multivariate statistical methods, partial least squares regression(PLSR), support vector machine(SVM), and random forest methods, to predict soil logarithm-transformed TC(logTC) using five fields(local scale) and a pooled(regional-scale) VNIR spectral dataset(a total of 560 TC spectral datasets), ii)assess the model transferability among fields, and iii) evaluate their up-and downscaling behaviors in Florida, USA. The transferability and up-and downscaling of the models were limited by the following factors: i) the spectral data domain, ii) soil attribute domain,iii) methods that describe the internal model structure of VNIR-TC relationships, and iv) environmental domain space of attributes that control soil carbon dynamics. All soil logTC models showed excellent performance based on all three methods with R^2> 0.86,bias < 0.01%, root mean squared error(RMSE) = 0.09%, residual predication deviation(RPD) > 2.70%, and ratio of prediction error to interquartile range(RPIQ) > 4.54. The PLSR method performed substantially better than the SVM method to scale and transfer the TC models. This could be attributed to the tendency of SVM to overfit models, while the asset of the PLSR method was its robustness when the models were validated with independent datasets, transferred, and/or scaled. The upscaled soil TC models performed somewhat better in terms of model fit(R2), RPD, and RPIQ, whereas the downscaled models showed less bias and smaller RMSE based on PLSR. We found no universal trend indicating which of the four limiting factors mentioned above had the most impact that constrained the transferability and scalability of the models. Given that several factors can impinge on the empirically derived soil spectral prediction models, as demonstrated by this study, more focus on their applicability and scalability is needed.

Antibiotic ciprofloxacin removal from aqueous solutions by electrochemically activated persulfate process:Optimization,degradation pathways,and toxicology assessment

Ciprofloxacin(CIP)is a commonly used antibiotic in the fluoroquinolone group and is widely used in medical and veterinary medicine disciplines to treat bacterial infections.When CIP is discharged into the sewage system,it cannot be removed by a conventional wastewater treatment plant because of its recalcitrant characteristics.In this study,boron-doped diamond anode and persulfate were used to degrade CIP in an aquatic solution by creating an electrochemically activated persulfate(EAP)process.Ironwas added to the system as a coactivator and the process was called EAP+Fe.The effects of independent variables,including pH,Fe^(2+),persulfate concentration,and electrolysis time on the systemwere optimized using the response surface methodology.The results showed that the EAP+Fe process removed 94%of CIP under the following optimum conditions:A pH of 3,persulfate/Fe^(2+)concentration of 0.4 mmol/L,initial CIP concentration 30 mg/L,and electrolysis time of 12.64 min.CIP removal efficiency was increased from 65.10%to 94.35%by adding Fe^(2+)as a transition metal.CIP degradation products,7 pathways,and 78 intermediates of CIP were studied,and three of those intermediates(m/z 298,498,and 505)were reported.The toxicological analysis based on toxicity estimation software results indicated that some degradation products of CIP were toxic to targeted animals,including fathead minnow,Daphnia magna,Tetrahymena pyriformis,and rats.The optimumoperation costswere similar in EAP and EAP+Fe processes,approximately 0.54€/m^(3).

Global assessment of nitrogen fertilizer:The SCOPE/IGBP Nitrogen Fertilizer Rapid Assessment Project

Nitrogen (N) availability is a key role in food and fiber production. Providing plant-available N through synthetic fertilizer in the 20th and early 21st century has been a major contributor to the increased production required to feed and clothe the growing human population.To continue to meet the global demands and to minimize environmental problems, significant improvements are needed in the efficiency with which fertilizer N is utilized within production systems. There are still major uncertainties regarding the fate of fertilizer N added to agricultural soils and the potential for reducing losses to the environment. Enhancing the technical and economic efficiency of fertilizer N is seen to promote a favorable situation for both agricultural production and the environment, and this has provided much of the impetus for a new N fertilizer project.To address this important issue, a rapid assessment project on N fertilizer (NFRAP) was conducted by SCOPE (the Scientific Committee on Problems of the Environment) during late 2003 and early 2004. This was the first formal project of the International Nitrogen Initiative (INI). As part of this assessment, a successful international workshop was held in Kampala, Uganda on 12 -16 January, 2004. This workshop brought together scientists from around the world to assess the fate of synthetic fertilizer N in the context of overall N inputs to agricultural systems, with a view to enhancing the efficiency of N use and reducing negative impacts on the environment.Regionalization of the assessment highlighted the problems of too little N for crop production to meet the nutrient requirements of sub-Saharan Africa and the oversupply of N in the major rice-growing areas of China. The results of the assessment are presented in a book (SCOPE 65)which is now available to provide a basis for further discussions on N fertilizer.

Cotton-harvester-flow simulator for testing cotton yield monitors

An experimental system was developed to simulate the pneumatic flow arrangement found in picker-type cotton harvesters.The simulation system was designed and constructed for testing a prototype cotton yield monitor developed at Mississippi State University.The simulation system was constructed to approximate the pneumatic cotton flow system of a cotton picker,and was capable of operating with varying cotton flow rates.The simulator was tested with different cotton flow rates,and the relationship between feeder rate and amount of conveyed seed cotton was found to be consistent.Further,the simulator was used to conduct tests with the novel optical cotton yield monitor,which proved accurate at measuring the amount of seed cotton flowing through the simulator.Finally,some differences between laboratory testing and field-testing were noted:seed cotton becomes fluffed and twisted when recycled through the simulator,and seed cotton stored in the laboratory tends to be of lower moisture content than cotton during harvest.These differences should be considered when using a laboratory simulator to test cotton yield monitors.