Water-saving irrigation strategies affect tuber water relations and nitrogen content of potatoes

Document Type: Research Paper

Authors

1 Irrigation Department, Faculty of Agriculture, Shiraz University, Shiraz, Iran

2 Irrigation Department, Faculty of Agriculture, Shiraz University, Shiraz, Iran.

Abstract

The dynamic and static deficit (DDI, SDI), partial root drying (DPRD, SPRD) and full (FI)
irrigation strategies were applied in Agria and Ramos potato cultivars in a semi-arid area. FI
received 100% of the potential evapotranspiration (ET); SDI and SPRD received 75% of ET
during the growth period; DDI and DPRD received 90% of ET in the first third, 75% of ET in
the second third and 50% of ET in the last third of growth period. Results showed that fresh
tuber yield and tuber nitrogen (N) content were negatively correlated meaning that by increasing
the tuber N content, tuber yield decreased. PRD irrigation strategy had significantly the highest
tuber N content than FI and DI. Dry matter water productivity (WPDM) was significantly
different between the irrigation strategies. The DI strategies had significantly higher WPDM than
FI and PRD ones. DDI and DPRD increased WPDM by 26 and 19% compared to SDI and SPRD,
respectively. WPDM in Ramos (1.08 kg m-3) was higher than Agria (0.82 kg m-3). The newly
introduced Dry Matter-Water Content Index (DMWCI) was higher in PRD and Agria than DI
and Ramos, respectively. Conclusively, the DI treatments are the recommended water savingirrigation strategies under these experimental conditions in terms of highest WPDM and greater
dry matter allocation to tubers, though the PRD irrigation strategy had higher tuber N content.
Ramos is the favored potato cultivar for processing industry based on its higher WPDM and tuber
dry matter content than Agria.


Keywords