关键词: 覆膜方式, 间作, 玉米, 产量, 光合特性, 水分利用效率

Abstract:

【Objective】This study explored the effects of different mulching methods on the production of photosynthetic substances and water use of maize under the intercropping mode of maize and soybean, aiming to determine the suitable mulching method for maize and soybean plantation in dryland agriculture in northern Shaanxi, so as to provide a basis for high-yield and efficient production of maize and soybean and ecological environment protection. 【Method】This study was conducted in irrigated land and nonirrigated land in 2022, using 'Zhonghuang 30' soybean and 'Xianyu 335' maize as materials. The two-factor complete randomized design was carried out, and the control group combined single crop (maize “M”, soybean “S”) and film mulching (bare land, interbrane “J”), and the test group combined intercropping crop (maize “M”, soybean “S”) and film mulching (bare land, interbrane “J” and whole film “Q”), with a total of 13 treatment groups. The characteristics changes of growth, photosynthesis, and water use efficiency of intercropped maize under different mulching methods were studied. 【Result】 (1) From jointing to silking stage, the growth space of intercropped maize was limited, resulting in a disadvantage in aboveground biomass of intercropped maize compared with monoculture. The biomass during the jointing stage of S/MQ, SQ/MJ, and SQ/MQ was 5.1%, 6.3%, and 1.7% higher than that of monoculture M, respectively; under intercropping, SJ/MJ maize plants had the fastest growth rate and a sharp increase in growth. SQ/MQ S/M, S/MJ, SQ/MJ, and SJ/M in dry land had a better promoting effect on the photosynthetic products of maize during the silking stage, and the aboveground biomass was 0.6%-105.9% higher than that of monoculture M. (2) To some extent, intercropping and mulching treatments improved the photosynthetic characteristics of maize, and the net photosynthetic rate (Pn) content of paddy maize. There was a certain degree of positive relationship between stomatal conductance (Gs), cellular CO₂ concentration (Ci) and transpiration rate (Tr). The photosynthetic parameters of SQ/MJ and SJ/MQ were relatively high, while SJ/M and SQ/MQ were lower than non film coated S/M; there was a weak negative correlation between Pn and Ci in dryland maize, and the effect of maize mulching was not significant among different treatments. The Gs of intercropping treatment was 5.7% -38.1% lower than that of monoculture M, and Tr was also reduced by 5.6% -25.6%. Only the Pn of SJ/M and SQ/M, as well as the Ci of SQ/MJ and S/M, were higher than monoculture M. (3) The intercropping film mulching had a significant impact on water use efficiency (WUE). The WUE of the intercropping treatment was 41.1% -74.0% higher than that of monoculture M, among which SJ/M, S/M and S/MJ were relatively high; among all treatments in arid land, SQ/MJ had the highest WUE (19.04 kg∙mm^-1∙hm^-2), followed by SJ/MJ (17.07 kg∙mm^-1∙hm^-2), and the WUE of SJ/M and SQ/M was significantly lower than that of monoculture M by 26.7% and 20.6%, respectively. (4) Compared with monoculture M, intercropping S/MJ between irrigated land and dry land SJ/M and SJ/MJ maize increased yields by 76.8%, 73.0%, and 72.3%, respectively, while soybean yield reduction was relatively less among all intercropping treatments, demonstrating higher economic benefits; dry land intercropping SJ/MJ and SJ/MQ maize increased production by 17.1% and 23.5%, respectively, while economic benefits decreased by 17.5% and 22.8%, respectively. 【Conclusion】Compared with single cropping M, SJ/MJ model improved the photosynthetic performance, biomass, and yield of maize in irrigated land, and improved system economic benefit and promoted water use efficiency. In dry land, through the complementary effect and resource allocation in the intercropping system, it maintained maize yield and improved water use efficiency, but the increase of total input in agricultural materials reduced the economic feasibility. Therefore, in the dryland agriculture of Northern Shaanxi, the intercropping planting pattern of maize with degradable film and soybeans with degradable film was recommended for both irrigated land and moderately irrigated dry farm, aiming to enhance water use efficiency, increase production and profitability, and promote sustainable ecological agriculture development.

Key words: coating method, intercropping, maize, yield, photosynthetic characteristics, water use efficiency