Grizzly Bears and Resource-Extraction Industries: Effects of Roads on Behaviour, Habitat Use and Demography

Abstract

In spring of 2010-2011, an experiment with treatments on soil water stress and sowing by stages of spring maize (Zea mays) was conducted in the central Jilin Province. The responses of maize emergence rate and yield to soil water stress were analyzed, and the assessment models of the emergence rate and reduction of yield caused by drought were established based on meteorological conditions. The results showed that during the study period, the relationship between maize emergence rate or per unit yield, and the soil moisture in 0-20 cm layer or soil available water content presented a significant quadratic function. The emergence rate and yield increased with the higher surface soil moisture, while decreased obviously under the drought condition. The emergence rate and yield were higher in the conditions of soil moisture in the range of 22%-24% or soil available water content in 50-65 mm, while the emergence rate and yield decreased obviously with the soil moisture less than 19% or available water content less than 35 mm. The soil moisture decreased 1% each, along with the emergence rate decreased by about 6% , and the yield decreased by about 7%. The soil available water content decreased by 10 mm, along with the emergence rate and yield decreased by about 13% and 14%, respectively. The indicators and models in this article could be applied to assessment and prediction of maize emergence rate and the reduction of yield caused by drought.