Combination of irrigation and fertilizer increases yield and economic profit in carrot production¹

Combinação entre irrigação e adubação aumentam a produtividade e rentabilidade econômica do cultivo de cenoura

HIGHLIGHTS:

The carrot yield increases due to the interaction between irrigation depth and fertilization.

The marginal cost of carrot crop yield approaches zero for irrigation depth values between 100 and 125% of ETc.

An irrigation depth unit increment may supply the need for fertilization without changing the carrot crop yield.

ABSTRACT

This study aimed to carry out an economical and productive analysis of carrot production using different irrigation depths and doses of fertilizer. A randomized block design was used arranged in a 6 × 4 factorial scheme, with three replicates. The treatments were constituted by six irrigation depths: (L₁: 210.5, L₂: 315.7, L₃: 421.0, L₄: 526.2, L₅: 631.5, and L₆: 736.7 mm) and four doses of fertilizer: (F₁: 226.9, F₂: 340.3, F₃: 453.8 and F₄: 567.2 kg ha^-1) applied via fertigation. At the end of the cycle, four carrot roots were collected per plot to estimate yield. The maximum estimated yield of the carrot was 95.4 t ha^-1, obtained using 478.1 mm of water and 538.8 kg ha^-1 of fertilizer. The best economic return was achieved with 482.0 mm of water and 460.0 kg ha^-1 of fertilizer, giving 95.0 t ha^-1. The combination of irrigation and fertilizer allows lesser amount of both to be used, giving greater response than when applied separately.

Key words:
Daucus carota; minimum cost; production function; mineral nutrition; yield