Abstract

Mixed forests have the potential to improve soil fertility, nutrient cycling, carbon storage and ultimately biomass production, and they have other benefits, such as improved risk management and protection against pests and diseases. In addition, they can serve as a silvicultural system for growing high-quality wood. This study aimed to check the comparable effect between Organic and chemical fertilizer NPK on growth traits of Castanea mollissima & to check the habitat growth of the Castanea seedlings in Shaqlawah Erbil treated with NPK & Irrigation in compare with control under local climate. the first experiment production of seedlings conducted in Agriculture college forestry department in greenhouse during May to September 2022 and the second experiment planting of seedlings in permanent field done in Shaqlawah /Erbil from October 2022 October 2023. RCBD factorial design used, two fertilizers used Peatmoss , silt+ 500ppmNPK and Sand as control .in September the seedlings harvested, the biometric traits height and diameter & biomass traits shoot and root measured. The results show highly significancy about effect of fertilizers on height of seedlings p value ≤0.05 during the 6 months of experiment So, the means of height of seedlings in NPK were 54 cm were the mean of peatmoss were 65 cm and 26 cm in sand control, sig. found in diameter trait the mean diameter for peatmoss were 2.8 mm ,2.3mm in NPK and 1.1 mm for control. And the results show significance between fertilizers effect on biomass growth traits (shoot, root) So the means of shott biomass of seedlings in NPK were 3.9 g. were and 6.7 g. in peatmoss were 1.5g. in control . about root biomass trait significant p value≤0.05   found between all treat medias if the mean root biomass 1.1g.for control were 3.7 g. for NPK and  6.6g.  for peatmoss. Even sig. differences found in chemical leaf nutrient conc. So, the means of Nitrogen content of seedlings in control were 87.5 ppm were the mean of NPK were 439.5ppm and 532.3ppm in peatmoss. results for the field experiment, the data value for the growth trait Height for the seedlings showed significant P value ≤0.05 during the experiment duration between NPK and control. So, the means of height of seedlings in NPK were 69.7 cm were the mean of control were 62.3cm, and the p value of ANOVA table were ≤0.05 for the diameter trait, significant differences found between control and NPK mean≤0.05 if the mean diameter for control were2.1 mm and 2.8 mm for NPK. About the irrigation treatment, the data value for the growth trait Height for the seedlings showed significant P value ≤0.05 between control and Irrigation treatment. So the means of height of seedlings in control without irrigation were 62.3 cm were the mean of irrigation were 68.3cm. for the diameter trait, significant p value found between control and irrigation mean≤0.05 if the mean diameter for control were 2.1 mm and 2.8 mm for irrigation. the data value for the growth trait (chemical content nutrients) for the seedlings in the field showed significant P value ≤0.05 between NPK and control. So, the means of Nitrogen content of seedlings in control were 132.66 ppm were the mean of NPK were 524.25ppm. generally, the species of Castanea mollissima can be plant in our mountain forestry areas in north of Iraq with treat with NPK fertilizer and Irrigation during first years of planting till the seedlings produce good amount of root systems to utilize and exploit more depth horizons of soil for water and nutrients. To gain this goal we recommend to have a mixed forest than pure, so it is better to plant Castanea mollissima with oak tree species Quercus aegilops, Quercus infectoria and Quercus libani which found in the mountain forests in Safeen mountain in Shaqlawah Erbil, to have facilitation between tree species.