Study On Spatio-temporal Window Of Saturated PAR On The Crop Canopy In Intercropping Alley Of Anneniaca Vulgaris Cv. Luntaibaixing

Under the oasis irrigation conditions of extreme drought in south Xinjiang basin, less than0.2hectares of arable land per capita, with the land circulation based on household contractsystem of responsibility linked to production had not been made a breakthrough. Thecontradiction between area expansion of forest fruit in the process of industrial developmentand grain and cotton production have become sharply, which was an outstanding problem torestrict forest fruit industry and rural economic development of the region. Thus resourceoutput in limited oasis and security of grain and cotton production should be taken intoaccount, which was an important issue to be solved. In this paper, the Armeniaca vulgaris cv.Luntaibaixing with grain （winter wheat） and cotton intercropping system were considered asthe object, and PAR of intercrop normal growth and development as the main line. Combinedthe method of field sampling with indoor analysis, the intercrop winter wheat and cottonphotosynthetic parameters, spatiotemporal window of saturated PAR of canopy and itsinfluencing factors were studied. The obtained results are as follows:The light response curve fitting of winter wheat and cotton at different growth periods andphotosynthetic parameters showed there was a big difference between winter wheat and cotton solarenergy demands at different growth periods. The light saturation point （LSP） of winter wheat was matureperiod<jointing period<filling period, while the LSP of cotton was three euphyllaperiod<squaring period<five euphylla period. The LSP of grain at filling period reached to amaximum of1429μmol·m^-2s^-1, and the minimum was1184micromol·m^-2s^-1at mature period. TheLSP of cotton was1702μmol·m^-2s^-1at five euphylla, and the lowest was1427μmol·m^-2s^-1at threeeuphylla period.The method of spatio-temporal window of PAR was adopted for planting space3m×4m,3m×5m,2m×6m,3m×6m and4m×6m, Luntaibaixing intercrop alley with spatio-temporalwindow of saturated PAR on canopy at different periods showed the LSP of intercrop determinedthe spatio-temporal window of saturated PAR on canopy. The PAR spatio-temporal window ofwinter wheat canopy in roadway was filling period<jointing period<mature period, while thespatio-temporal window of PAR winter wheat canopy in roadway was five euphyllaperiod<squaring period<three euphylla period. However, the spatio-temporal window ofsaturated PAR on the canopy has been completely closed in cotton at the five euphylla period.Stepwise regression analysis showed the spatio-temporal window of saturated PAR oncanopy in the intercrop alley was affected by solar altitude, planting space, height, crown, LAI,Tr and other factors besides the LSP of intercrop at different periods. Among them, planting spaceand plant hight×crown radius is the major factor affecting spatiotemporal window of saturatedPAR on intercrop canopy.