Distribution of Forms of Copper and their Association with Soil Properties and Uptake in Major Soil Orders in Semi-arid Soils of Punjab,India

Profiles of semi-arid-zone soils in Punjab, northwestern India, were investigated for different forms of copper (Cu), including total Cu, diethylenetriaminepentaacetic acid (DTPA)–extractable Cu, soil solution plus exchangeable Cu, Cu adsorbed onto inorganic sites, Cu bound by organic sites, and Cu adsorbed onto oxide surfaces. When all soils were considered, total Cu content ranged from 7 to 37 mg kg^?1, while DTPA-extractable and soil solution plus exchangeable Cu contents ranged from 0.30 to 3.26 mg kg^?1 and from 0.02 to 0.43 mg kg^?1, respectively. Copper adsorbed onto inorganic sites ranged from 0.62 to 2.6 mg kg^?1 and that onto oxide surfaces ranged from 2.0 to 13.2 mg kg^?1. The Cu bound by organic sites ranged from 1.2 to 12.2 mg kg^?1. The magnitudes of different forms of Cu in soils did not exhibit any consistent pattern of distribution. Organic matter and size fractions (clay and silt) had a strong influence on the distribution of different forms of Cu. The content of all forms of Cu was generally greater in the fine-textured Alfisols and Inceptisols than coarse-textured Entisols. Soil solution plus exchangeable Cu, Cu held onto organic sites, and and Cu adsorbed onto inorganic sites (crystalline) had significant positive correlations with organic carbon and silt contents.The DTPA Cu was positively correlated with organic carbon, silt, and clay contents. Total Cu content strongly correlated with silt and clay contents of soils. Among the forms, Cu held on the organic site, water soluble + exchangeable Cu, and Cu adsorbed onto oxide surface were positively correlated with DTPA-extractable Cu. The DTPA-extractable Cu and soil solution plus exchangeable Cu seems to be good indices of Cu availability in soils and can be used for correction of Cu deficiency in the soils of the region. The uptake of Cu was greater in fine-textured Inceptisols and Alfisols than coarse-textured Entisols. Among the different forms only DTPA-extractable Cu was positively correlated with total uptake of Cu.     

Field Scale Mapping of Surface Soil Clay Concentration

The surface soil clay concentration is a useful soil property to map soils, interpret soil properties, and guide irrigation, fertilizer, and agricultural chemical applications. The objective of this study was to determine whether surface soil clay concentrations could be predicted from remotely sensed imagery of bare surface soil or from soil electrical conductivity for a 115 ha field located in Crisp County, Georgia. The soil clay concentrations were determined for soil samples taken at 28 field locations. Three different data sources–an aerial color photograph image, two infrared bands from an ATLAS data set, and the electrical conductivity of the surface soil layer were used in the research. Principal components analysis was applied to the color photograph image, whereas the ratio of two infrared bands was applied to the ATLAS data set. Filtering was applied to both resulting images. The distribution of soil electrical conductivity was derived from the measured soil electrical conductivity data by spatial analysis. Statistical relationships between soil clay concentrations and the principal component 3, the ratio of two ATLAS infrared bands, and the soil electrical conductivity were analyzed, and three linear equations were derived with r ² values 0.83, 0.52, and 0.78, respectively. The distribution of the soil clay concentrations was derived based on these three equations. Six levels of soil clay concentrations were classified in these three methods, and the advantages and disadvantages were discussed. The predicted and measured soil clay concentrations, based on additional soil samples from 30 field locations, were compared using linear regression (r ²=0.76, 0.45, and 0.77 for the three methods). The overall accuracy for these methods were 84%, 66%, and 76%, respectively. The principal components method had the highest accuracy in our research, while the result for the depressional areas is the best from the ratio method.     

CORRELATION BETWEEN YIELD,MUST ATTRIBUTES AND NUTRITIONAL STATUS OF THE GREEK RED WINE GRAPE VARIETY ‘AGIORGITIKO’

The appropriate tissue and sampling time for the Greek wine-grape variety ‘Agiorgitiko’ nutritional diagnosis was to be evaluated by relating leaf tissue nutrient contents with the yield and must potassium (K), pH, total soluble solids (TSS), and titratable acidity (TA). At bloom, véraison and harvest, leaves opposite the basal cluster (LOBC) and youngest mature leaves (YML) were harvested, and soil and berry samples were collected from six vineyards in Nemea, Greece. Petiole K concentration of the LOBC was found to be better correlated with the yield, TSS, TA and must K than the blade or whole leaf K content; the contrary was observed in nitrogen (N), phosphorus (P), calcium (Ca), and magnesium (Mg) concentrations. The LOBC reflected better the nutritional status of the variety compared to the YML. Regarding the sampling time, petiole K presented stronger correlations with yield and must K, TSS, TA at harvest whereas N and P at bloom and véraison.     

麦棉套种膜上灌溉节水增产机理研究

试验研究采用麦棉套膜上灌——土壤水分——作物——农田小气候理论体系,测定膜上灌灌水条件下的水流特征和土壤水分循环特点,麦棉共生期作物生育特性和农田小气候的相互关系。揭示出麦棉套膜上灌和棉花膜上灌分别节水２９％和４７％,小麦增产３．８％及棉花增产１１．８％的节水增产机理