بررسی اثر کود نیتروژن و تراکم کاشت بر کیفیت علوفه و جمعیت علف های هرز ذرت (.Zea mays L) در نظام کشت جنگل زراعی

Agroforestry is one of the sustainable agricultural aspects in which the perennial woody plants grow in selective method with annual plants, domestic or both. This experiment was conducted to evaluate the effects of different sowing densities and nitrogen fertilizer rates on quantitative and qualitative characters of corn forage yield as well as weed population in an agroforestry system with orange trees. The treatments consisted of 4 nitrogen fertilizer levels of 0, 100, 200, and 300kg N/ha (allocated to main plots) and 4 sowing densities of 80000, 110000, 140000 and 170000 of corn plants per hectare (allocated to sub plots). The treatments were arranged as split plots based on a randomized complete block design with three replications. The forage dry matter yield followed an increasing trend as nitrogen fertilizer and sowing density increased. The highest forage dry matter of 33000 kg/ha was achieved at 170000 plant/ha density while received 300kg/ha of nitrogen. The highest crude protein (CP) percentage was obtained at 110000 plant/ha while received 100Kg N/ha. The yield CP increased as nitrogen fertilizer application increased. The highest digestible dry matter percentage was obtained at 110000 plant/ha with 200 Kg N/ha application. Weed dry matter weight per square meter significantly decreased as nitrogen fertilizer and sowing density increased to 300 Kg N/ha and 170000 plant/ha, respectively. Soil pH in 100Kg N/ha and 170000 plant/ha treatment significantly increased compared to other treatments. The largest orange fruit diameter was observed in 100Kg N/ha and 80000 plant/ha which was not significantly different from 300kg N/ha and 17000 plant/ha treatment.