Effects of furrow depth on soil hydrothermal properties and corn germination withalternate row/bed planting under subsurface drip irrigation

摘要

Alternate row/ bed planting (AP) is a new sowing method with a furrow; and seeds are sown below the furrow bottom, which can significantly improve the corn germination under subsurface drip irrigation. Afield experiment was carried out to investigatethe effects of three furrow depths of 0 (HO), 10 (H10) and 15 cm (HI 5) on soil hydrothermal properties and spring corn germination. The results showed that the soil moisture content and temperature around the seeds gradually increased and decreased as the furrow depth increased under the same irrigation amount, respectively. As a result of higher soil moisture content, the emergence duration of H10 and HI5 were 3 and 4 d shorter than that of HO and the emergence rates were increased by 14.6% and 16.3%,respectively. From sowing-emergence, the soil temperature around seeds ofHIO and HI5 was lower than the appropriate temperature, which resulted in their emergence rates <90%. After sowing, the decomposition of nutrients in endosperm accelerated and thesoluble sugar content in residual seeds increased as the furrow depth increased. With the faster emergence speed and higher emergence rate, the plant height and dry biomass of aboveground plant parts of HIO and HIS were bigger than HO. Compared with H10,the root length of HI 5 decreased by 16.4%) in the third leaf stage. Based on these results, HIO was suitable for AP. Covering the furrow with biodegradable plastic film or backfilling the furrow before the sixth leaf stage would improve the corn germination under AP.