不同覆盖材料和方式对旱地春小麦产量及土壤水温环境的影响

在西北半干旱雨养条件下,研究了不同覆盖材料、覆盖方式对春小麦土壤水分、土壤温度、产量及重要农艺指标的影响。试验以无覆盖栽培为对照(CK),设置了秸秆覆盖及地膜覆盖(平作全地面覆膜、微垄全地面覆膜、大垄半覆膜),共8个覆盖处理。结果表明:处理间土壤水分、土壤温度、产量等都存在显著差异;各覆盖处理均较CK显著增产7.6%~44.9%,其中以微垄全地面覆膜增产最显著,处理间单位面积穗数的差异是引起产量差异的主要结构因素;与CK相比,全生育期0~200cm土壤水分含量各覆盖处理均高于CK 0.3%~1.7%,其中以平作黑膜全覆盖(B2)和微垄白膜全覆盖(C1)最高;比较全生育期0~25cm土壤平均温度差异,除小麦秸秆覆盖(A1)和大垄黑膜半覆盖(D2)较CK分别降低1.4和0.9℃外,其他6个覆盖处理较CK提高0.3~1.8℃,其中以平作白膜全覆盖(B1)增温幅度最大;但进一步分时期、分土层比较发现,各覆盖处理在不同生育时期和土层,基本出现较CK增墒与降墒、增温与降温的双重效应。各处里增墒点次比例为54.2%~83.3%,相应降墒点次比例为16.7%~45.8%,时期上,增墒效应以开花期和灌浆期最明显、降墒效应以孕穗期最明显;土层上,增墒效应以20~40cm土层最明显、而降墒效应以60~90cm土层最明显。各处理较CK增温的点次比例为4%~100%,时期上,覆盖增温效果以灌浆期最明显,降温效果以均分蘖期和开花期最高;从土层来看,以土壤25cm处增温幅度最高。

Effect of different mulching materials and methods on soil moisture and temperature and grain yield of dryland spring wheat in northwestern China

This study determined effects of different mulching materials and methods on soil water,soil temper-ature,grain yield (GY)and important agronomic parameters of spring wheat in a semi-arid rain fed area of northwestern China.A total of 8 mulching treatments were tested in this study.These included straw mulc-hing,plastic film mulching such as flatten culture and whole mulching,micro-ridge and whole mulching,large ridge and half mulching,compared with a non-covered treatment as control (CK).There were significantdifferences in soil moisture,soil temperature and GY among the various treatments.Compared to the CK, mulching significantly increased GY by 7.7% to 44.9%,with the maximum yield increase occurring in micro-ridge and whole mulched plastic film treatments.The spikes per unit area (SPUA)were the main factor re-sponsible for difference in GY.There was a highly positive correlation (r =0.788 * )between SPUA and GY. Compared to the CK,mulching increased the average soil moisture in the 0-200 cm soil layer during the entire growth period by 0.3% - 1.7%,and the highest soil moisture levels were those of micro-ridge and whole mulched white film (C1 )and large ridge and half mulched black film (D2 ).Both mulching with wheat straw (A1 )and large ridge and half mulched black film (D2 )decreased average soil temperature in the 0-25 cm soil layer during entire growth period by 1.4 and 0.9℃,while soil temperatures of the other 6 mulching treatments were increased by 0.3 -1.8℃.The maximum warming occurred in flatten culture and whole mulched white film (B1 )treatments.However,more detailed analysis of spatio-temporal differences in soil temperature and soil moisture revealed that the various treatment effects were most strongly seen in different soil layers or in different growth periods.Soil moisture data were recorded at 48 time points in each treatment.Each mulching treatment had 26-40 points with soil moisture higher than the CK,and 8-22 points lower than the CK.Dur-ing the entire growth period,mulching predominantly increased soil moisture at the flower-filling stage,and decreased soil moisture in the booting stage.Mulching-induced soil moisture increases were most evident in the 20-40 cm soil layer,and mulching tended to decrease moisture in the 60-90 cm soil layer.Soil temperatures were measured and recorded at 25 time points in each treatment,and each of the mulching treatments varied in numbers of points higher (range 0 to 24 points)or lower (range 1 to 25 points)than CK plots.The maximum warming was observed in the 25 cm soil layer.