| Currently, lack of the effective groundcover management approaches in orchards is oneof the major problems in groundcover soil management of Eastern Gansu Province, aiming atthis problem, a field experiment was carried out in Qingyang City of Gansu Province in2012to determine the effects of different mulching approaches associated with soil groundcovermanagement in Red Fuji apple orchards on fruit yield and soil moisture as well as soiltemperature. Two orchards were selected, including orchard1#with highly economicalproductivity and orchard2#with lowly. Three treatments were designed in the present study,containing locally conventional practice, optimized film mulching measure and optimizedmaize straw mulching measure. Our main findings were as follows:1. Optimized straw mulching measure significantly increased fruit yield by40.80%and54.35%compared with control both in the two orchards, respectively. Though optimized filmmulching measure increased fruit yield by5.57%and34.27%relative to control in the twoorchards, there was no significant difference in fruit yield between control and optimized filmmulching measure. Besides, optimized straw mulching measure significantly increased thesingle fruit weight about11.84%and13.16%compared with control. Meanwhile, optimizedstraw mulching measure obviously increased average fruit number per plant about42.64%inorchard2#. Overall, straw mulching approach had a greater contribution to the increase offruit yield relative to film mulching in our study.2. Compared with control, optimized film mulching measure significantly increased soiltemperature during the whole growing stage, especially early spring, there were a significantincrease of3.6℃and3.9℃in soil temperature in depth of5cm soil layer under optimizedfilm mulching measure. The differences in soil temperature during summer and autumn werelower than that of early spring, representing a significant increase about2.6℃,2℃,2.3℃,2.9℃and2.4℃compared with control. There was very smooth in the variation of soiltemperature under optimized straw mulching measure compared with that of control, and thesignificant decline of1.4℃and4.4℃in soil temperature in depth of5cm of soil layerduring early spring were observed, by1.4℃and0.3℃occurred in summer, whereas soiltemperature in depth of5cm of soil layer under optimized straw mulching measuresignificantly increased0.1℃,0.1℃and0.4℃from August to October compared withcontrol, which exhibited warming effects on soil temperature. Dynamics in soil temperaturefrom different soil groundcover managements gradually reduced with the increase of soil depth.In terms of the differences in soil temperature at the same times among three treatments,increasing and decreasing extent of soil temperature under optimized film mulching measurewere higher than those of optimized straw mulching measure and control. The difference inaccumulated temperature in the depth of5cm soil layer from eight to fourteen o’clock underoptimized film mulching measure was1179.5℃, increasing by239℃compared with control,whereas that of optimized straw mulching measure was only336℃and decreased by604.5℃and843℃compared with control and optimized film mulching measure. Dynamics ofsoil temperature in5-15cm of soil layer were different from those in depth of5cm fromfourteen to twenty o’clock, the difference in accumulated temperature under the threetreatments were-327℃,-301.5℃and-56℃in depth of soil layer and164.5℃,285.5℃and134.5℃in depth of15cm of soil layer, temperature range was in the order of optimized filmmulching measure> control> optimized straw mulching measure. The difference inaccumulated temperature under the three treatments were-670.5℃,-916.5℃and-369.5℃in depth of5cm soil layer during the night. In details, variation in soil temperature underoptimized film mulching measure was more intensity than those of optimized straw mulchingmeasure and control, especially the rapid increase of soil temperature during the short-term,and the slow increase or decline of soil temperature under optimized straw mulching measurerelative to control, which maintained the favorable environment associated soil temperaturefor the growth and development of apple trees.3. Optimized film mulching measure and optimized straw mulching measuresignificantly increased soil moisture in0-60cm of soil layer compared with control, and thedifferences among three treatments gradually shrunk with the increase in soil depth. Soilmoisture in spring was in the order of optimized straw mulching measure> optimized filmmulching measure> control, meanwhile, soil moisture in the treatments received optimizedstraw mulching measure and optimized film mulching measure averagely increased by8.67%and18.27%in orchard1#and by11.12%and19.94%in orchard2#compared with control,respectively. Drought resulted in the obvious decline in soil moisture during June, allowingfor the order of optimized film mulching measure> optimized straw mulching measure>control, soil moisture in orchard1#under optimized film mulching measure and optimizedstraw mulching measure significantly increased by39.95%and6.22%compared with control,and those numbers in orchard2#were by38.44%and25.59%, respectively. The differences insoil moisture during July among three treatments were similar with June in which occurred,soil moisture in orchard1#under optimized film mulching measure and optimized straw mulching measure significantly increased by17.75%and12.67%compared with control, andthose numbers in orchard2#were by16.02%and15.73%,respectively. As the increase in soildepth, there were no significant differences in soil moisture among three treatments in80-100cm of soil layer. In this study, optimized straw mulching measure provided morefavorable conditions for the uptake of soil moisture in0-60cm soil layer during the wholegrowing stage, especially in early spring, which the absorbing root of apple trees mainlydistributed. |
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