No abstract

1995. Effects of placement of urea with a urcase inhibitor on seedling emergence, N uptake and dry matter yield of wheat. Can. J. Plant Sci. 75: 449-452. Growth chamber studies were conducted to determine the effect of seed-placed and surhce dribble-banded urea fertilizer, with and without the addition of turc lerrels of the urease inhibior N-(n-butyl) thiophosphoric triamide (nBIPT) on seedling emetgence, vegetative yield and nitrogen accumulation ofhard red spring wheat. Seedling emergence was reduced with increasing applications ofseed-placed urea, but nBTPT rcduced the damage from seed-placed urea. The O.l5% inhibior level was as effective as the O.25% level in rcducing seedling damage.Vegetative yield increased with application of urea fertilizer but no difference in vegetative yield resulted from varying fertilizer placement or additions of nBTPT. Nitrogen accumulation increased with increasing N application and with the use of the urease inhibitor, indicating an increase in N arrailability due to sloring of urea hydrolysis. Use of the urease inhibior nBTPT shorrs promise in reducing seedling damage from seed-placed urea fertilizer and increasing the utilization of seed-placed and surface-applied urea fertilizer on a black Chernozemic soil. Further snrdies are in prqgress to assess the performance of IETPT unter field conditions.

The relationship between remotely sensed surface temperature (T) and normalized difference vegetation index (NDVI) was studied over China with 10-day composite Advanced Very High Resolution Radiometer (AVHRR) data at 8-km spatial resolution. Results showed that the slope of the relationship between T and NDVI (T/NDVI slope) could be determined effectively during the growing season with a certain range of NDVI. The derived T/NDVI slope from image windows was significantly correlated to in situ soil moisture (r50.77, p,0.01). Based on determination of wet and dry edges of T/NDVI space and the relationship between soil moisture and the T/NDVI slope, a new approach was proposed to estimate distributed soil moisture. Using the approach, the derived soil moisture approximated the conditions recorded on the ground.