EVALUATING THE EFFECTS OF NUTRIENT EXCLUSION ON GROWTH PERFORMANCE, YIELD, AND NUTRIENT EFFICIENCY IN WINTER RAPESEED (BRASSICA NAPUS L.) IN RAINFED CONDITIONS

Abstract

Rapeseed (Brassica napus L.) is one of the world’s most important oilseed plants, although it is the yield in the rain-fed ecosystems, especially under arid and semi-arid environments, which remains low due to inadequate nutrient management. This research was conducted to evaluate the effect of nutrient omission on the growth, yield and nutrient use efficiency of winter rapeseed in Chakwal, Pakistan. The goal was to assess how nutrient sources could be better used for increasing yields, especially with the incorporation of FYM. A field experiment was conducted over two consecutive rabi seasons at the PMAS Arid Agriculture University Research Farm using a randomized block design with seven treatments: control, PK (-N), NK (-P), NP (-K), NPK (-S), NPKFYM (-FYM), and NPKS + FYM. Nutrient application rates were 80:50:40:30 kg ha⁻¹ for N, P, K, and S, with 10 t ha⁻¹ of FYM. Treatments were thus assessed in terms of yield, yield components, seed/straw nutrient content, agronomic utilization efficiency and nutrient use efficiency. The findings revealed that the NPKS + FYM treatment improved yield and nutrient uptake to the highest level, with a seed yield of 1265 kg ha⁻¹. This treatment also increased nutrient utilization, plant use efficiency, and partial factor productivity, thus indicating the advantages of using organic plus inorganic nutrients. However, exclusions of nutrients resulted in yield declines, and out of these, nitrogen and potassium had the greatest decline. Therefore, from the present investigation, it revealed the role of balanced nutrient supply and organic inputs to maximize the rapeseed production under rainfed environments. It satisfies a knowledge gap because it blends organic materials with chemical fertilizers that were not often incorporated before. The research benefits current and advancing sustainable agriculture practices as it enlightens nutrient management relating to the climatic zone of the study area.