Study On Irrigation Scheduling Of Peppers And Melons Under Mulch Drip Irrigation With Brackish Water In Ningxia Greenhouse

For optimal irrigation system of brackish water drip irrigation, respectively with brackish water (salinity2.7g/L),freshwater (salinity0.18g/L),mixed water (brackish water and water mixed by1:1,salinity1.6g/L) three kinds of water quality, analyzed the effect of pepper and melon with5kinds irrigation on the growth and yield. The plant height, photosynthesis, yield, fruit quality and soil characteristics were measured. The results showed that:(1) Freshwater could improve plant yields and irrigation water use efficiency under the same irrigation amount.However, brackish water could significantly reduce crop yields.(2) The mixed water was the most appropriate irrigation mode for pepper, the rotation of brackish and fresh water irrigation mode was very suitable for melon.(3) Long-term irrigation with brackish water inhibited the vegetative growth.Plant chlorophyll content in soil was inversely proportional to the cumulative amount of salt ions.The mixed water caused crop plant height, and made the stem diameter growth fast in prophase but slow in late.Both brackish-freshwater rotation and freshwater mode could promote the plant height, stem diameter and leaf area growth.(4) Long-term irrigation with brackish water could increase the organic content of pepper and melon, meanwhile increased pepper’s soluble solids content, and decreased melon’s total soluble sugar content.The mixed water reduced the organic acids content of pepper and melon, while the melon fruit’s soluble solids, total soluble sugar and Vc content were higher.Different water treatment without much impacted for the soluble protein content.(5) The higher salinity of irrigation water, the lower soil volumetric water content.At the same time the water soluble salt content was higher. Brackish water made the upper’s soil salinity less than the lower’s. Soil salinity was significantly lower under the two kinds of brackish-freshwater rotation mode. If the rotation follow the growth period,the salt accumulation in the soil layers can significantly reduce.(6) Irrigated with mixed water reduced the effects of salinization of soil salinity was better than freshwater.(7)Tests showed that under the12m3/667m2irrigation quota and40kg/667m2nitrogen fertilizer mode the freshwater or brackish-freshwater rotation irrigation would get high yiela and good quality melon.