Simultaneous effect of deficit irrigation and salinity on nutrient's content and dry matter of Canola (Brassica napus L.) and soil salinity profile under greenhouse conditions

Water scarcity and soil salinity are two important limiting factors for agricultural production.Canola crop, with high resistance to soil salinity and adaptation to different climatic conditions of Iran, has great ability for satisfying the main part of the country’s requirements for edible oil.This research was carried out in 2006 on winter canola (Brassica napus L., cv. Zarfam) under greenhouse condition at the Agriculture and Natural Resources Research Center, Yazd. The experiment was performed as a complete randomized block design with three replications that contained salinity and irrigation water factors. Salinity factor had four levels of S1=3-4, S2=6-7, S3=9-10 and S4=12-13 dS/m and irrigation water factor had three levels of irrigation after W1=30, W2=50 and W3=80 percent of management allowed moisture depletion. Soil texture was sandy loam. The results showed that salinity and deficit irrigation were significantly effective on dry matter production (p<0.05). Under simultaneous salinity treatments and deficit irrigation,increasing salinity to S3 significantly increased the canola dry matter by 14.6% and increasing salinity to S4 level decreased the plant dry matter production by 10.9%. Dry matter of W3 treatment was 6.5% less than W1 treatment. Deficit irrigation and the combined impact of salinity and deficit irrigation did not have significant effect on nutrient (P, K, Ca and Mg) content. Salinity effect was significant (p<0.01) on Na, Cl and Zn content. S3 and W2 treatments had the highest amount of Cu, Zn and Fe. Study of soil salinity at the end of the experiments showed that 0-5 cm soil layer has the highest salinity level; salinity of the middle layer (5-10 cm) is less than the other two layers and the salinity of 10-20 cm is higher than the middle layer and lower than the upper layer.