EFFECT OF IRRIGATION AND NITROGEN, PHOSPHORUS AND POTASSIUM RATE AND PLACEMENT ON TOMATO FRUIT YIELD AND SIZE

Abstract

Tomato (Lycopersicon esculentum Mill. ’Cabot’) was grown in Atlantic Canada on two soil types that contained either "high" (350–500 kg ha−1) or "low" (85–150 kg ha−1) soil P (Bray no 2). Application of water by trickle irrigation increased total (ripe + green fruit) marketable yields in 3 of 4 yr. Since there were no irrigation versus NPK fertilizer treatment interactions, all treatments were irrigated in subsequent experiments. On the "high" P soil, maximum yield was attained with side-banding P at 8.7 kg ha−1 at transplanting with preplant broadcast N and K. At the same broadcast N and K rates, it required 35 kg ha−1 of broadcast P to achieve the same yield. Similarly, on the "low" P soil with the same rates of N and K broadcast, banding P at rates up to 17.5 kg ha−1 was approximately four times as efficient as either banding or broadcasting all three nutrients in terms of increasing yield. Maximum ripe and total fruit yields, respectively, for the all-banded and all-broadcast methods (80 kg N, 70 kg P and 66 kg K ha−1) were 24 and 17% less than attained when P was banded at 35 kg ha−1 with the same rates of broadcast N and K. Doubling the N and K rates with P increased to 70 kg ha−1 further increased yields by 28% for the P-banded plus N and K broadcast method. However, these high N and K rates seriously depressed yields for the all-banded application. Banding P with broadcast N and K also produced larger fruit than either of the other two application methods. Results clearly demonstrated the yield advantage of irrigation and the superiority of side-banding P with broadcast N and K over banding or broadcasting all three nutrients for maximizing yields and fertilizer-use efficiency for tomato production in the Atlantic Region of Canada. Key words: Tomato, broadcast, banding, phosphorus efficiency, irrigation