To evaluate the effects of straw belt-covering on soil temperature and yield of winter wheat in rain-fed semiarid region in Northwest China, five mulching modes, including flat field planting without any mulching (CK), whole plastic film mulching (PM), straw mulching by 30 cm covering belt with an interval of 30 cm planting belt with three-row sowing (SM1), straw mulching by 40 cm covering belt with an interval of 40 cm planting belt with four-row sowing (SM2), and straw mulching by 50 cm covering belt with an interval of 50 cm planting belt with five-row sowing (SM3), were set by two-year fixed-site trails in 2013-2015. The results showed that soil temperature significantly varied among different growth stages and soil layers in all treatments. SM1, SM2 and SM3 significantly decreased soil temperature by 1.0-1.3 ℃, 0.7-0.9 ℃ and 0.7-1.1 ℃ in the 0-25 cm soil layer, respectively. The mulching had double effects with increasing and decreasing soil temperatures. The straw mulching significantly increased soil temperature in the duration of seedling to overwintering stage, but greatly decreased soil temperature in the duration of reviving to mature stage. The temperature-increasing effect of film mulching was stronger than that of straw mulching, which was opposite to the temperature-decreasing effect. Straw mulching significantly reduced in the effective accumulated temperature and the daily temperature variations during the whole growth stages. The effective accumulated temperature under straw mulching decreased by 3.4-33.5 ℃·d, and the soil temperature difference decreased by 0.6-2.0 ℃. During over-wintering stage, the straw mulching showed a higher average soil temperature (0.2-0.3 ℃) and negative accumulated temperature (0.4-17.0 ℃·d) than those under the CK. The straw mulching significantly increased grain yield by 11.9%-19.5%. The variations of spikes per unit area were the main factor responsible for yield difference. The findings indicated that that straw mulching method is suitable for winter wheat production in rain-fed region of Northwest China.
为了明确秸秆带状覆盖对西北半干旱雨养区冬小麦田地温和产量形成的影响,于2013—2015年连续进行2年定位试验,设不覆盖露地(CK)、全膜覆土穴播(PM)、秸秆带状覆盖(覆盖带和种植带各30 cm,播种3行,SM1)、(覆盖带和种植带各40 cm,播种4行,SM2)、(覆盖带和种植带各50 cm,播种5行,SM3)5个处理.结果表明: 各处理在不同生育时期、不同土层土壤温度存在显著差异.与CK相比,SM1、SM2和SM3处理全生育期0～25 cm土层土壤温度分别比CK显著降低1.0～1.3 ℃、0.7～0.9 ℃和0.7～1.1 ℃.不同时期比较,覆盖处理存在增温和降温的双重效应,秸秆覆盖在苗期-越冬期具有提高地温的作用,返青期-成熟期具有降温效应,增温效应覆膜>秸秆覆盖,而降温效应秸秆覆盖>覆膜.同时,秸秆覆盖降低了全生育期土壤有效积温和日变化幅度,全生育期有效积温较CK降低3.4～33.5 ℃·d,土壤温差较CK降低0.6～2.0 ℃;秸秆覆盖在越冬期平均温度比CK高0.2～0.3 ℃、负积温比CK高0.4～17.0 ℃·d.秸秆覆盖较CK增产11.9％～19.5％,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.因此,秸秆带状覆盖适宜在西北雨养区旱地冬小麦产区推广应用.
Keywords: maize straw; plastic film mulching; semiarid area; soil temperature; strip covering; winter wheat.