[Border effect and physiological characteristics of broomcorn millet under film mulching on ridge-furrow for harvesting rainwater model in the semi-arid region of Northern Shaanxi, China].

To explore the border effect and physiological characteristic of broomcorn millet growing under different film mulching on ridge-furrow for harvesting rainwater models in the semi-arid region of Northern Shaanxi, China, a three-year field experiment was conducted with four different widths of ridge and furrow, and the bare land flat sowing as the control (NM). The width of ridge and furrow varied as ridge: furrow = 40 cm: 40 cm (P40), 60 cm: 60 cm (P60), 80 cm: 80 cm (P80), and 100 cm:100 cm (P100). The results showed that the wider the width of furrow and ridge was, the stronger the border advantage and the border effect index of the yield were. With the increase in width of furrow and ridge, the yield increasing effect of side rows increased with the maximum of 207.7%, and the yield increasing effect of middle rows decreased with the minimum of 10.3%. P60 reached the highest yield within three years. The yield contribution rate of side rows was higher than that of middle rows (P < 0.05). The chlorophyll contents, Ch1 a/Ch1 b, and photosynthetic rate of side rows were higher than those of middle rows among the different harvesting rainwater models. The wider the width of furrow and ridge was, the stronger the photosynthetic capacity of side rows was, and the weaker the photosynthetic capacity of middle rows was. The optimal type of ridge and furrow was P60 in the semi-arid region of Northern Shaanxi.