Smart Control of Water Flow and Depth Within Rice Field for Improving Irrigation Management and Mitigating Methane Emission.

A two-year field experiments were carried out at the Experimental Farm of the Central Laboratory for Agricultural Climate, Agriculture Research Center, Egypt during 2015 and 2016 successive rice seasons. such investigation aimed to study the productivity and CH4 emission capacity of two Egyptian rice varieties (Sakha101 and Sakha106) under different irrigation water depths (4, 8 and 12 cm) from the soil surface. Innovated siphon container were connected to a water valve to maintain the continually of the water head at the desired depths. The water depth treatments were laid out in a randomized complete block design with four replications for each variety in both seasons. A combined analysis was used between the two varieties in each season to interpret the data. Plant height cm, root length cm and chlorophyll SPAD at 30 and 55 days after transplanting, panicle length cm, number of tillers m-2, number of grains panicle-1, number of unfilled grains panicle-1, 1000-grain weight, grain yield t ha-1, straw yield t ha-1 and harvest index were recorded. Methane fluxes were measured by using closed chamber method. Water depth affected significantly all studied characteristics. The maximum values of most of the studied characteristics were recorded at 8 cm water depth. On the other hand, the lowest values were observed at 12 cm water depth. CH4 emission was dramatically reduced by decrease the water depth. There was significant correlation coefficient between methane emission and all studied agronomic characteristics except 1000-grain weight and harvest index. The methane emission from rice fields decreased significantly with the increase of plant growth and yield. Irrigation water depth at 8 cm seem to be the recommendable treatment to achieve the promising rice yield and methane mitigation value.