水保所知识产出(1956---)知识库

Plastic film mulching (PM) has a compensatory effect on crop growing degree days by increasing soil temper-
ature. However, only few studies addressed the question whether a terminal time for the compensatory effect
window exists and if it exists how it can be quantified. The objective of this study was to use the logistic equation
to describe the cumulative crop plant height and to quantify the compensatory effect. Crop apical meristem
emergence was used as the reference for the terminal time of the compensatory effect window. A three-year field
experiment (2013–2016), conducted under continuous PM in a typical winter wheat (Triticum aestivum L.) and
summer maize (Zea mays L.) rotation on the Loess Plateau, Northwest China, indicated that the logistic equation
performed well in representing and quantifying the compensatory effect of PM. The compensatory effect of PM
reached a plateau during winter wheat growing seasons due to the lack of increased soil temperature during
regreening stage, and during summer maize growing seasons due to unfavorably delayed senescence. The ter-
minal time can be estimated during winter wheat and summer maize growing seasons from thermal time nodes at
the maximum slope (t 2 ) and second inflection point (t 3 ), respectively. The compensatory coefficients could be
estimated by thermal time intervals of (0, t 1 ) and (t 1 , t 2 )in winter wheat growing seasons and thermal time
internals (0, t 1 ), (t 1 , t 2 ), and (t 2 , t 3 ) in summer maize growing seasons, respectively. Compensatory coefficients
tended to increase with maize plant development. The minimum data requirement using a logistic equation to
calculate compensatory coefficients includes data for staged plant height and mean daily air temperature.