Subsurface drip irrigation reduces cadmium accumulation of pepper (Capsicum annuum L.) plants in upland soil

Given that Cd pollution in dry land has aroused wide public concern, numerous remediation technologies has been utilized, yet there are limited cost-effective techniques that do not affect the original planting patterns. Fortunately, irrigationmanagement can meet these requirements, while the effects of irrigation practices on Cd uptake by crops in slightly Cd-polluted upland soil remain elusive. Here, we aimed to investigate howthe irrigation methods altered the Cd availability in soil, Cd accumulation in plants, microorganism population in soil, rootmorphology, and enzyme activities in soil and plants. We examined three irrigation treatments - surface drip irrigation (DI), subsurface drip irrigation (SDI), alternate-rows irrigation (ARI), and the control conventional furrow irrigation (CFI). The results showed that SDI remarkably reduced Cd content in roots, shoots and fruits, increased yield, and improved root growth and activity in soil of 20-40 cm compared to other treatments, though the Cd concentration in rhizosphere was not decreased significantly. The microbial population and enzyme activities in rhizosphere and enzyme activities in leaves and roots in SDI and ARI were basically higher than DI and CFI. Therefore, SDI has the prominent potential to reduce Cd uptake by crops in upland soil polluted with low Cd. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

This study found that subsurface drip irrigation significantly reduced the cadmium content in roots, shoots, and fruits, increased yield, and improved root growth and activity in soil at a depth of 20-40 cm compared to other treatments, although the cadmium concentration in the rhizosphere was not significantly decreased. The microbial population and enzyme activities in the rhizosphere of subsurface drip irrigation and alternate-rows irrigation were basically higher than that of surface drip irrigation and conventional furrow irrigation.