Effects of Varying Levels of Poultry Manure on Growth and Yield of Canola (Brassica napus L.) under Kabul Agro-climatic Conditions

Canola (Brassica napus L.) is one of the key oilseed crops worldwide, serving as a vital source of edible oil, livestock feed, and biofuel. In Afghanistan, canola production faces significant challenges due to declining soil fertility and over-reliance on expensive chemical fertilizers. Poultry manure, as a low cost and nutrient-rich organic fertilizer, offers a sustainable alternative for improving crop productivity. However, limited scientific information is available regarding the optimal poultry manure application rate for canola under Kabul’s agro-climatic conditions. Therefore, an experimental research was conducted at Kabul University Agricultural Research Farm during the 2025 cropping season using Randomized Complete Block Design (RCBD) with three replications and four treatments. The study aimed to evaluate Effects of Different Levels of Poultry manure on Growth, Yield, and Yield Components of Canola. The findings of the study revealed that the application of poultry manure significantly influenced on growth, yield and yield components of canola. Overall, the application of 8-ton poultry manure ha^-1 had better performance than control. The maximum plant height (117.45 cm), number of branches plant^-1 (5.65), number of leaves plant^-1 (39.77), number of siliques plant^-1 (184.61), silique length (6.01 cm), number of seeds silique^-1 (18.39), thousand seed weight (3.40 g), seed yield (2.74 t ha⁻¹), biological yield (9.87 t ha⁻¹), and harvest index (27.76%) were all recorded in T4. The lowest values for all parameters were observed in the control treatment (T1). It is recommended that use 8 tons of poultry manure ha-1 in order to realize optimal seed yield and biological yield of the crop.