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A four-year trial was set up to test the feasibility of growing oleic sunflower in a very strongly saline wasteland with drip irrigation in the Ningxia plain of Northwest China. The soil salinity expressed as electrical conductivity of the saturation paste extract (EC) was around 28 dS/m, and soil nutrient was deficient in the upper 120 cm depth. The experiment included five soil matric potential (SMP) treatments, with the SMP at 20-cm depth immediately under the emitters maintained to be higher than −5, −10, −15, −20 and −25 kPa after sunflower establishment. Drip irrigation consistently created a favourable soil moisture and low-salinity region in the root zone when the SMP was maintained higher than −25 kPa. The sunflower dry seed yield decreased by 3.8 % for each unit increase in seasonal average soil salinity in the root zone. Plant vegetative growth, yield characteristics, irrigation frequency and irrigation amount all increased with the increase in SMP from −25 to −5 kPa, and the highest irrigation water use efficiency was available when the SMP was between −10 and −15 kPa (the amount of applied water was around 750 mm). Leaching of salts by drip irrigation gradually turned the very strongly saline soil into a moderately saline soil. This research suggests that drip irrigation can be successfully used in oleic sunflower cultivation in this highly saline soil and a SMP threshold between −10 and −15 kPa is suggested for irrigation scheduling. [ABSTRACT FROM AUTHOR]

Abstract: A 4-year trial was set up to test the feasibility of growing waxy corn (Zea mays L. var. ceratina Kulesh) in a highly saline wasteland with drip irrigation in the Ningxia plain, northwest China. The original soil salinity expressed as electrical conductivity of the saturation paste extract (EC e ) averaged 28dS/m in the 0–120cm depth. The experiment included five soil matric potential (SMP) treatments in which the SMP at 20cm depth below the drip emitters was controlled higher than −5, −10, −15, −20 and −25kPa after waxy corn establishment. The results showed that drip irrigation created a favorable soil condition for waxy corn growth through forming and maintaining a high moisture and low salinity region in the root zone when the SMP was maintained higher than −25kPa. Waxy corn growth and yield parameters increased with the increase of SMP from −25kPa to −5kPa, but their responses to SMP decreased with the prolonged period of cultivation. Irrigation frequency and irrigation amount decreased significantly as SMP decreased from −5kPa to −25kPa, and the highest irrigation water use efficiency (IWUE) was available when the SMP was around −15kPa in 2005, and was between −20kPa and −25kPa in successive years. After years of cultivation and drip leaching, the highly saline soil gradually changed to a moderately saline soil. This research suggests that drip irrigation can be successfully used in growing waxy corn in dry and highly saline conditions after appropriate management strategies are adopted. [Copyright &y& Elsevier]