اثر خشك كردن ناحيه اي محيط ريشه (PRD) بر ميزان عناصر غذايي، ماده خشك، شاخص برداشت و توزيع سيستم ريشه در كلزا (.Brassica napus L)، رقم زرفام تحت شرايط گلخانه اي

Effects of PRD on nutrient content, dry matter, harvest index and root distribution in canola (Brassica napus L.) under greenhouse conditions

PRD (partial drying of the root zone) is a new deficit irrigation technique in which one side of the root system is irrigated, while the other side is dry. In this research, effect of PRD on nutrient content, dry matter, harvest index, and root distribution in canola {Brassica napus L., var. Zarfam) under deficit irrigation and relatively high irrigation water salinity was studied in Agriculture and Natural Resources Research Center of Yazd in 2006. The PRD experiment had five treatments (Tx : irrigation of both sides of the plants, T2: alternate irrigation on both sides of the plants, T3: irrigation only on the right side, T4: irrigation of right side of the plants without having a vertical division barrier in the boxes, and T5: alternate irrigation of the plants without having a vertical division barrier in the boxes). In Tt to T3 treatments, the boxes were halved by a thin vertical division barrier so that water cannot move from one side to the other. Electrical conductivity of irrigation water was 6.56 dS/m. The results showed that water use efficiency of Ti was 0.376 and that of T2 treatment was 0.679 kg/m3 and the difference was significant at 1% probability level. Halving the amount of irrigation water in T2, with respect to T1? caused the content of P, K, Mg, Na, CI, Cu, Zn and Fe to increase and of Mn and Ca to decrease in canola plants. T2 treatment had 0.8% more dry matter and 0.09% less harvest index as compared to Tb These differences were not significant statistically. The root distribution systems showed that the plants which were irrigated on both sides had more uniform deep roots and the plants which were irrigated only from one side had roots on that side only. The root distribution was effective on nutrient uptake.