Impact of humic acid and macronutrients on growth and yield of gobi sarson (Brassica napus L.) and succeeding pigeon pea (Cajanus cajan L.)

The present study was undertaken to assess the impact of humic acid and macronutrients on the growth and yield parameters of a gobi sarson-pigeon pea cropping system. The experiment involved the cultivation of gobi sarson (variety GSC 7) during the Rabi season of 2022-23 and pigeon pea (variety AL-882) during the Kharif season of 2023-24. The field experiment was conducted at the Agronomy Research Farm, Lovely Professional University and was laid out in a randomized block design (RBD) with three replications. A total of nine treatments comprising different combinations and concentrations of humic acid and macro-nutrients were evaluated to study their effects on the growth and yield attributes of both crops. Among various treatment T9 [Humic acid (20 g/L) + Sulphur (5 g/L) + Magnesium (5 g/L)] showed maximum plant height, number of primary and secondary branches, stem girth, dry matter accumulation and chlorophyll content in pigeon pea showed higher values than gobi sarson, likely due to residual soil nutrient enhancement. Yield attributes improved with an increase in humic acid and macronutrients and treatment T9 [Humic acid (20 g/L) + Sulphur (5 g/L) + Magnesium (5 g/L)] had maximum number of pods per plant, pod length (cm), number of seeds per pod, test weight (g) and seed yield (q/ha) in pigeon pea crop in comparison to gobi sarson crop. Results from the study revealed that among the various treatments, the application of T9 [Humic acid (20 g/L) + Sulphur (5 g/L) + Magnesium (5 g/L)] had a significant impact on various growth and yield attributes. Pigeon pea crop had more yield as a succeeding crop as soil absorbs more nutrients from the previous grown crop (gobi sarson) and enhances the growth and yield characters. Humic acid macroelements significantly increases test weight and seed yield, demonstrating its positive impact on the overall crop production of gobi sarson-pigeon pea crop.