Different Regimes of Nitrogen and Invasion of Thrips on Onion in Balochistan, Pakistan - I
Muhammad Faheem Malik,
To determine the relation between fertilizer and thrips infestation in onion (Allium cepa), six different levels of nitrogen (N) with constant phosphorus (P) and potassium (K) were tried in, Quetta, Balochistan, Pakistan. The soil of the region is sandy loam, alkaline, moderate in calcium and very poor in NPK. The soil and climate are well suited for onion cultivation. Low and optimum doses of nitrogen have no effect on thrips population. Maximum mean total thrips infestation (267.9 and 269.3 per plant) was observed at high doses of nitrogen application (200 and 250 Kg ha-1). Crop yield has shown direct relations with increased fertilizer doses up to 200 Kg ha-1 nitrogen. Beyond that dose a rapid decline in yield was observed. Maximum yield (15220 Kg ha-1) and cost benefit ratio (1: 1.44) with minimum mean total thrips infestation (157.2) was observed by applying 150-100-100 Kg ha-1 NPK, respectively.
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