Soil solarization for weed control in carrot

Ricardo Antonio Marenco,Denise Castro Lustosa

doi:10.1590/s0100-204x2000001000014

Abstract

Soil solarization is a technique used for weed and plant disease control in regions with high levels of solar radiation. The effect of solarization (0, 3, 6, and 9 weeks) upon weed populations, carrot (Daucus carota L. cv. Brasília) yield and nematode infestation in carrot roots was studied in São Luís (2º35' S; 44º10' W), MA, Brazil, using transparent polyethylene films (100 and 150 mm of thickness). The maximum temperature at 5 cm of depth was about 10ºC warmer in solarized soil than in control plots. In the study 20 weed types were recorded. Solarization reduced weed biomass and density in about 50% of weed species, including Cyperus spp., Chamaecrista nictans var. paraguariensis (Chod & Hassl.) Irwin & Barneby, Marsypianthes chamaedrys (Vahl) O. Kuntze, Mitracarpus sp., Mollugo verticillata L., Sebastiania corniculata M. Arg., and Spigelia anthelmia L. Approximately 40% of species in the weed flora were not affected by soil mulching. Furthermore, seed germination of Commelina benghalensis L. was increased by soil solarization. Marketable yield of carrots was greater in solarized soil than in the unsolarized one. It was concluded that solarization for nine weeks increases carrot yield and is effective for controlling more than half of the weed species recorded. Mulching was not effective for controlling root-knot nematodes in carrot.

Highlights

Weed management in carrot relies mainly on the use of herbicides in conventional agriculture
Transparent polyethylene films are recommended for soil solarization because of its high transmittance of short wave (0.3 - 3 μm) radiation, and its low transmittance of long wave (4 - 40 μm) radiation
In the first sampling (15 days after planting (DAP)), the reduced growth of weeds made it difficult to evaluate the effect of solarization on individual weed species, only data for the sum of weeds were obtained

Summary

Introduction

Weed management in carrot relies mainly on the use of herbicides in conventional agriculture. This is because it is seeded directly in narrow rows, which makes tillage unrecommended because of the injury it causes to roots, and on account of increasing cost or uncertainty in labor supply that makes timely. Consistent with the current search for non-hazardous methods for controlling weeds is the application of integrated weed management strategies, which takes into account the need to increase agricultural production and to determine economic losses, risks to human health, energy and environmental factors, and potential damage to non-target organisms (Shaw, 1982)

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Results