Abstract

以春小麦"陇春27"为试材,研究半干旱区旱地全膜覆土穴播对土壤水热效应及小麦产量的影响。结果表明:与裸地平作(CK)相比,全膜覆土穴播(PM)和全沙覆盖平作(SM)增温效果呈"挂钩型",增温效果在小麦拔节期前最为明显,PM 0-25 cm土壤平均温度较CK提高1.8 ℃,全沙覆盖平作提高1.4 ℃,拔节后PM和SM的增温效果逐渐减弱直至消失,而在成熟期又呈现较弱的增温效果。PM和SM能提高小麦出苗后耗水速度并加大耗水量,其中,小麦拔节到扬花期耗水量增加最多,分别较CK平均增加54.93%和31.54%,且此阶段越是干旱,促进耗水作用越明显,PM促进作用大于SM。PM和SM能显著提高小麦阶段性水分利用效率(<em>WUE</em><sub>b</sub>),其中PM以苗期提高最多,2a平均较CK提高365.17%,SM拔节期提高最多,2年平均较CK提高119.00%。PM和SM在增温、促进耗水作用下使小麦各生育期提前并增加单株干重,产量较CK分别平均增加432.28%和375.82%, 水分利用效率(<em>WUE</em>)分别平均增加351.51%和338.29%,而且越干旱年份增产效应愈加明显。可见,PM和SM在越为干旱的年份促进耗水、增产和提高<em>WUE</em>的作用越显著,PM效果强于SM。;The differences between the timing of natural rainfall and demands of crops for water during seasonal drought is one of the main factors restricting crop production in semi-arid areas.As a new agricultural technology, the use of plastic film as mulch to cover the entire soil surface, combined with bunch planting of wheat with no-tillage has several effects; the plastic captures evaporating water and so suppresses evaporation and maintains soil moisture.This significantly improves rainfall use efficiency, allows the full use of light and heat resources, and significantly increases yield of wheat, flax and other crops.Therefore, the use of plastic film as mulch with bunch planting has been widely applied in dryland agriculture in the middle and eastern parts of Gansu Province, China.However, systematic methods for the use of plastic mulch in wheat production are still lacking; in particular, research is lacking on the effects of plastic film mulching with bunch planting on soil temperature, moisture, water consumption, water use efficiency (<em>WUE</em>), and effects on the various growth stage of wheat and on dry matter accumulation.To understand how this new technology improves crop development and yield and how it affects soil hydrothermal conditions, we designed and implemented a field experiment using three treatments: the use of plastic film as mulch to cover the entire soil surface with bunch planting (PM), the use of sand mulching on the entire field and traditional scattered seed planting (SM) and un-mulched planting and with traditional scattered seed planting (CK).The study was carried out to determine the effects of different mulching methods on soil temperature, moisture and yield of spring wheat (<em>Triticum aestivum </em>L.) in the semi-arid area in drylands in central Gansu.In this experiment, we used Long Spring 27 (<em>Triticum aestivum </em>L.) as the test material to study the effects of different mulching methods on soil temperature, moisture and spring wheat yield in a semi-arid area.The results showed that PM and SM increased soil temperature in the entire growth period for spring wheat; this increase in soil temperature is most obvious before the jointing stage of wheat.PM and SM could result in a 1.8 ℃ and 1.4 ℃ increase in average soil temperatures in the 0-25 cm soil layer, respectively, compared with CK.After the jointing stage, the warming effect of PM and SM gradually weakened or disappeared, although it reappeared in a weaker state as the wheat matured.PM and SM could improve the rate of water consumption and increase water consumption after seedling emergence.Water consumption was largest during the jointing-flowering stage and PM and SM increased water consumption up to 54.93% and 31.54%, respectively, compared with CK.With increased drought intensity the effects of the treatments were more obvious at the jointing-flowering stage.PM and SM could improve biomass water use efficiency of wheat (<em>WUE</em><sub>b</sub>) significantly; the improvement was highest (up to 365.17%) at the seedling stage of PM and at the jointing stage of SM (up to 119.00%), compared with CK.PM and SM treatments resulted in increased soil temperatures and improved soil water consumption; therefore, these treatments extended the growing period for spring wheat and increased the dry matter weight per plant.Also PM and SM increased yield by 432.28% and 375.82% and increased <em>WUE</em> by 351.51% and 338.29%, respectively, compared with CK; with increased drought intensity, yield increased more obviously with the PM and SM treatments.Therefore, PM and SM can significantly promote water consumption, increase yield and improve <em>WUE</em> by a higher percentage in a drought year, although the effect is stronger with PM than with SM.

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