Nutrient availability in the rhizosphere of rice grown with plastic film mulch and drip irrigation

The combined use of plastic film mulch and drip irrigation for rice production could result in high yields and significant water savings.However, little is known about soil nutrient availability in this system.The objective of this laboratory experiment was to measure the availability of soil N, P, K, Zn, and Mn in two treatments: (i) conventional flood irrigation (FI) and (ii) plastic film mulch and drip irrigation (PFM-DI).Rice (Oryza sativa L. cv T-04) was sown in plastic boxes containing 80 kg soil.Bulk and rhizosphere soil samples were collected at four growth stages (i.e., tillering, jointing, full heading, and grain filling).Soil NH4-N and exchangeable Mn concentrations were lower in the PFM-DI treatment than in the FI treatment.In contrast, concentrations of NO 3 -N, available K, available Zn, and easily reduced Mn were higher in the PFM-DI treatment than in the FI treatment.There was no significant difference in Olsen P between FI and PFM-DI treatments.Soil NH 4 -N, available K and exchangeable Mn concentrations were lower in rhizosphere soil than in bulk soil.In contrast, NO 3 -N and Zn concentrations were higher in rhizosphere soil than in bulk soil.Neither available P nor easily reduced Mn concentrations differed between rhizosphere and bulk soil.Our results indicated that compared with conventional flood irrigation, the plastic film mulch plus drip irrigation system increased soil nutrient availability.