Field performance of alternate wetting and drying furrow irrigation on tomato crop growth, yield, water use efficiency, quality and profitability

Sustainable irrigation method is now essential for adaptation and adoption in the areas where water resources are limited. Therefore, a field experiment was conducted to test the performance of alternate wetting and drying furrow irrigation（AWDFI） on crop growth, yield, water use efficiency（WUE）, fruit quality and profitability analysis of tomato. The experiment was laid out in randomized complete block design with six treatments replicated thrice during the dry seasons of 2013-2014 and 2014-2015. Irrigation water was applied through three ways of furrow： AWDFI, fixed wetting and drying furrow irrigation（FWDFI） and traditional（every） furrow irrigation（TFI）. Each irrigation method was divided into two levels： irrigation up to 100 and 80% field capacity（FC）. Results showed that plant biomass（dry matter） and marketable fruit yield of tomato did not differ significantly between the treatments of AWDFI and TFI, but significant difference was observed in AWDFI and in TFI compared to FWDFI at same irrigation level. AWDFI saved irrigation water by 35 to 38% for the irrigation levels up to 80 and 100% FC, compared to the TFI, respectively. AWDFI improved WUE by around 37 to 40% compared to TFI when irrigated with 100 and 80% FC, respectively. Fruit quality（total soluble solids and pulp） was found greater in AWDFI than in TFI. Net return from AWDFI technique was found nearly similar compared to TFI and more than FWDFI. The benefit cost ratio was viewed higher in AWDFI than in TFI and FWDFI by 2.8, 8.7 and 11, 10.4% when irrigation water was applied up to 100 and 80% FC, respectively. Unit production cost was obtained lower in AWDFI compared to TFI and FWDFI. However, AWDFI is a useful water-saving furrow irrigation technique which may resolve as an alternative choice compared with TFI in the areas where available water and supply methods are limited to irrigation.

Methane emissions from rice fields under continuous straw return in the middle-lower reaches of the Yangtze River

A three-year experiment was conducted in the middle-lower reaches of the Yangtze River in China to study the influence of continuous wheat straw return during the rice season and continuous rice straw return in wheat on methane （CH 4 ） emissions from rice fields in which, the rice-wheat rotation system is the most dominant planting pattern. The field experiment was initiated in October 2009 and has continued since the wheat-growing season of that year. The analyses for the present study were conducted in the second （2011） and third （2012） rice growing seasons. Four treatments, namely, the continuous return of wheat straw and rice straw in every season （WR）, of rice straw but no wheat straw return （R）, of wheat straw but no rice straw return （W） and a control with no straw return （CK）, were laid out in a randomized split-plot design. The total seasonal CH 4 emissions ranged from 107.4 to 491.7 kg/ha （2011） and 160.3 to 909.6 kg/ha （2012）. The increase in CH 4 emissions for treatments WR and W were 289% and 230% in the second year and 185% and 225% in the third year, respectively, in relation to CK. We observed less methane emissions in the treatment R than in CK by 14%-43%, but not statistically significant. Treatment R could increase rice productivity while no more CH 4 emission occurs. The difference in the total CH 4 emissions mainly related to a difference in the methane flux rate during the first 30-35 days after transplant in the rice growing season, which was caused by the amount of dissolved oxygen in paddy water and the amount of reducible soil materials.