Uptake Process and Recovery of co-situs Applied Polyolefin-Coated Urea as Affected by Release Pattern on Corn (Zea mays L.) under Humid Climate in Northeastern Japan(Plant Production Science Soil Science)

Two years of field experiments were conducted to (i) determine dent corn (Zea mays L.) growth and nitrogen (N) uptake from split-dressed urea, co-situs applied polyolefin-coated urea with linear (POCU-70) and sigmoidal (POCU-30+S60) release using the ^N tracer method, and (ii) compare the uptake process and the recovery of co-situs applied POCUs in 1994 and 1995 at the Kawatabi Experimental Station of Tohoku University, located in northeastern Japan. The differences in the dry-matter production and total N uptake among the N sources were very small. However, the dry-matter production in 1994 is significantly higher than in 1995 due to unusual low rainfall and rich sunshine. During the early growth stage, the relative recoveries of POCU-70 and POCU-30+S60 were low, but already significantly greater than that of urea. After the middle growth stage, POCU-S60 was recovered higher than the others. The recoveries of POCU-S60 gradually increased from 55% of dissolved N during the middle growth stage to 72% at the harvest, where those of POCU-70 increased from 30 to 61%. At the end of the growing season, the recoveries of urea, POCU-70 and POCU-30+S60 were 51, 61 and 70%, respectively. The significant difference in years and the interaction among the N source and year were caused by the low recovery of urea that appeared in 1995 due to normal rainfall. The better synchronization between the N dissolution from POCU-S60 and N requirement by corn would increase the recovery of the POCU-30+S60 treatment and contribute to the lower susceptibility to yearly variations in climate

Inorganic Constituents in Soil

This open access book is a must-read for students of and beginners in soil science. In a well-organized and easy-to-follow manner, it provides basic outlines of soil minerals, new methods and recent developments in the field, with a special focus on visual aids. The chapters on primary minerals, secondary minerals, non-crystalline inorganic constituents and inorganic constituents sensitive to varying redox conditions will help readers understand the basic components of soils. Further, readers are introduced to new analytical methods with the aid of microscopy and recent developments in the field. Uniquely, the book features case studies on the identification and isolation methods for vivianite crystals from paddy field soils, as well as a useful procedure for identifying noncrystalline constituents such as volcanic glasses and plant opals, which can also be applied to other soils depending on the local conditions. Given its focus and coverage, the book will be useful to all readers who are interested in agronomy, plant production science, agricultural chemistry and environmental science. In addition, it can help biogeochemists further expand their research work on the rhizosphere of wetland plant roots, iron and phosphate dynamics, etc

Factors Affecting Organic Carbon Accumulation in Humus Horizons of Andosols from the Tohoku University World Andosol Database

Poster Sessio

Organic Carbon Accumulation in Andosols: (3) Occurrence of Apatite and Biotite in Young and Matured Volcanic Ash Aoils, and Discussions on Nutrient Supply for Ecosystems

Symposium Pape

Recent Trends in the Nutrient Status of the Paddy Field Soil in Japan and Related Topics(Frontiers in Rice Science -from Gene to Field-,The 100^<th> Anniversary of Tohoku University, International Symposium)

Paddy rice production is important for Asian people because rice is their traditional staple diet and it is a reliable crop for them. Rice shows second highest yield per ha next to maize and sustainability of paddy rice production is excellent. High sustainability of paddy rice production is at least partly due to flooding and nutrient supply through irrigation water. Yield and quality of paddy rice are better than those of upland rice. In this paper, we review characteristics of the paddy field soils and recent trends in the nutrient status of Japanese paddy field soils, and then we introduce our recent research topics on N, P, S and Cd in the paddy field soil

Recent trends in the nutrient status of the paddy field soil in Japan and related topics

Special Revie

Effects of water management on vivianite crystallization on paddy rice roots

Poster Sessio

Organic Carbon Accumulation in Andosols: (2) Contribution of Aluminum-humus Complexes to Carbon Accumulation in Non-allophanic Andosols

Symposium Pape