AGRO-ECONOMIC IMPACT OF INTERCROPPING CANOLA AND ONION ON SOME SUGAR BEET VARIETIES UNDER DIFFERENT NITROGEN RATES

Abstract

Two field experiments were conducted at the Agricultural Experimental Station, Faculty of Agriculture, Cairo University, Giza, Egypt during 2013/2014 and 2014/2015 seasons to study the agro-economic effect of three nitrogen fertilization rates (60, 80 and 100 kg N/fed), three cropping systems (sugar beet sole, sugar beet + canola and sugar beet + onion) and four multi-germ sugar beet varieties (Farida, Carola, Gloria and Demapoly). The experimental design was a split- split plot in randomized complete block arrangement with three replications. Results revealed that increased N rates, from 60 to 100 kg fed-1 and Growing sugar beet as a sole crop significantly increased root weight, root yield and sugar yield in both seasons. Sugar beet variety Carola was superior in root weight, root yield and sugar yield followed by the variety Farida in both seasons. The main effects of nitrogen, cropping systems and varieties had no significant effect on root quality traits in terms of total soluble solids%, sucrose%, purity% and extractable sucrose% during the two seasons. The highest significant values of mean root weight (1.019 and 1.109 kg), root number (28.69 and 28.21 thousand plants/fed), root yield (29.35 and 31.47 ton/fed) and sugar yield (3.72 and 3.75 ton/fed) resulted from fertilized sugar beet sole plants with 100 kg N/feddan in the 1st and 2nd seasons, respectively. Irrespective of cropping systems, fertilized sugar beet varieties Farida and Carola plants with 100 kg N/ feddan gave the highest mean values of root weight, root yield and sugar yield during the two seasons. The interaction of cropping systems x varieties had a significant effect on mean root weight, root number, root yield and sugar yield during the two seasons. Among the tested varieties, sole planting of Carola had maximum beet root weight (0.953 and 1.043 kg), beet root yield (28.65 and 31.07 ton/fed) and sugar yield (3.69 and 3.74 ton/fed.) in the 1st and 2nd seasons, respectively, followed by Farida when planted as a sole crop. The highest and significant root and sugar yields were obtained from the sugar beet variety Carola when planted as a sole crop and fertilized with 100 kg N/feddan during the two seasons. It was observed that irrespective of sugar beet varieties and cropping systems, the highest cost of production and gross revenue were recorded when plants received 100 kg N/feddan. The cost of sugar beet (sole) production was LE. 5350 fed-1 against the production costs of LE. 5650 and 6950 fed-1 when sugar beet was intercropped with canola and onion, respectively. The highest gross revenue (19002 and 17650 LE/fed) resulted from intercropping sugar beet varieties Carola and Gloria, respectively with onion under 100 kg N/feddan. The maximum net returns was obtained under combination of sugar beet variety Carola + onion (12052 LE/ fed), followed by sugar beet variety Gloria + onion (10700 LE/fed) when plants fertilized with 100 kg N/feddan. The maximum cost benefit ratios of 1.73 and 1.54 were obtained with nitrogen rate of 100 kg/feddan under combination of sugar beet variety Carola + onion and sugar beet variety Gloria + onion, respectively. The results showed that for obtaining higher net returns from the unit area, preference may be given to intercrop sugar beet variety Carola with onion and fertilized plants with 100 kg N feddan-1.