Transplanting time and seedling age affect water productivity, rice yield and quality in north-west India

Early transplanting of rice during periods of high evaporative demand can result in mining of groundwater. In Indian Punjab, the water table is currently falling at 0.4-0.9 m per year. Hence, there is urgent need to adopt water saving practices to enhance grain yield and water productivity. The present study was run at Punjab Agricultural University (PAU) to investigate the effect of transplanting dates (June 15, June 25 and July 5) and seedling age (30,45 and 60 days) on yield, quality and water productivity of two rice cultivars differing by their duration: 144 days for PAU 201, 156 days for PR 118. Delay in transplanting from June 15 to June 25 or July 5 did not show any influence on yield and quality of rice, but irrigation water saving were 4.6 and 14.0%, respectively. The corresponding increase were: apparent crop water productivity (ACWP): 7.1 and 14.5%: total crop water productivity (TCWP): 9.8 and 19.2%; real crop water productivity (RCWP): 9.4 and 13.3%. PAU 201 cultivar recorded 9.3% higher grain yield and 3.7% higher irrigation water saving than PR 118. Differences were also significant for ACWP. TCWP and RCWP. The positive relationship between transplanting time and ACWP, TCWP and RCWP were accentuated for the medium duration cultivar (PAU 201). The transplanting of 30 days old seedlings gave significantly higher grain yield, apparent, total and real water productivity over 60 days old seedlings. So the transplanting of medium duration cultivar PAU 201 may be delayed up to July 5 and that of long duration cultivar PR 118 up to June 25 for substantial saving of irrigation water without any disadvantage in yield or grain quality. (C) 2012 Elsevier B.V. All rights reserved.