Soil moisture and nitrate-nitrogen dynamics and economic yield in the greenhouse cultivation of tomato and cucumber under negative pressure irrigation in the North China Plain

摘要

A feld experiment was carried out for two years to investigate the benefts of negative pressure watersupply on surface soil water content, nitrate-nitrogen (NO3?-N) distribution in the soil profle, economicyield and water and fertilizer use efciency of tomato and cucumber under greenhouse cultivation inthe North China Plain. The experiment included two irrigation treatments: drip irrigation with nutrientsolution (DIN) and negative pressure irrigation with nutrient solution (NIN). The results showed that theNIN treatment had a relatively stable soil moisture (about 87% of feld capacity), and the fuctuation ofsoil water content in the 0–20cm soil layer was 20.6%–25.0% during the experiment period in 2014–2015,which was less than the range of 19.2%–28.1% in the DIN treatment. In both the DIN and NIN treatments,the NO3?-N at the end of the four growing seasons was mainly distributed in the 0–40cm soil layer andshowed a gradually increasing trend as the number of cultivation years increased. Compared with the DINtreatment, the NO3?-N content in the 0–60cm layer of the NIN treatment was signifcantly decreasedby 19.7%–28.0% after the fourth growing season. The NIN treatment produced the highest economicyield with lower water and nutrient input than the DIN treatment, however, no signifcant diference wasobserved in tomato and cucumber yield in the two years. Average irrigation water use efciency (WUEi) andpartial factor productivity of fertilizer (PFPf) over the study period were all signifcantly improved under theNIN treatment relative to the DIN treatment, with increases of 26.2% and 25.7% (P0.05), respectively.Negative pressure water supply not only maintained a high fruit yield, but signifcantly increased WUEi andPFPf, indicating a great advantage in water and fertilizer saving compared with drip irrigation.