Effects of drip discharge flux and soil wetted percentage on drip irrigated potato growth with film mulch

Abstract

China has the largest potato (Solanum tuberosum L.) production, while the average potato tuber yield is still lower than the world level. In order to improve potato cultivation, field experiments were conducted at the Special Potato Experimental Station, China Agricultural University, Rizhao, Shandong Province in 2016 and 2017 to explore the effects of drip discharge fluxes (1.38 L/h, Q1; 2.0 L/h, Q2; and 3.0 L/h, Q3) and soil wetted percentages (15%, P1 only in 2016; 25%, P2; 50%, P3; and 75%, P4 only in 2017) on soil water distribution and potato growth under drip irrigation with film mulch. With the same soil wetted percentage, Q1 provide drier soil at shallow layer and wetter at deep layer than Q2 and Q3. With the same drip discharge flux, the average daily soil matric potential decreased and soil matric potential range increased with the soil wetted percentage increasing. For different drip discharge fluxes, Q2 and Q3 had 10.4% and 13.6% significantly greater IWUE than Q1 in 2017. For different soil wetted percentages, P3 had significantly 15.9% and 8.6% more marketable tubers, and 19.1% and 11.2% more large plus jumbo tubers than P1 and P2 in mass, respectively in 2017. P3 had 17.4% and 14.7% significantly greater yield than P2 and P4 in 2016 and 15.1% and 7.6% significantly greater than P1 and P2 in 2017, respectively. The IWUE decreased with the soil wetted percentage increasing. Drip discharge flux Q2 and soil wetted percentage P3 was a more favorable combination for potato growth in this area.