Weed Biomass and Weed Species Diversity of Juvenile Citrus Trees Intercrop with some Arable Crops

Patience Mojibade Olorunmaiye,Stephen Olaoye Afolayan

doi:10.15835/nsb417166

Patience Mojibade Olorunmaiye, Stephen Olaoye Afolayan

Open Access

https://doi.org/10.15835/nsb417166

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Abstract

A preliminary study was carried out to evaluate the performances of eight crops in the intercrop of citrus with arable crops at the National Horticultural Research Institute (NIHORT) Ibadan, Nigeria. Eight arable crops: maize, cucumber, sweet potato, Corchorus olitorius, large green, grain amaranth, Mucuna pruriens var. utilis, and groundnut were intercropped with young citrus trees in the early planting season of 2010 with sole citrus as control. The experiment was laid out in a completely randomized block design with three replicates. Data were collected on weed flora, weed density and weed dry weight. Results showed that the relative frequencies of weeds in all the plots were less than 4% at both 6 and 9WAP. Gomphrena celosoides, Oldenlandia corymbosa and Tridax procumbens were most preponderant in appearing in all the plots. Tridax procumbens had a consistent relative frequency (2.34%) in all the plots except in citrus/maize plot (0.78%) at 9 WAP. Significantly lower broadleaf weed densities were obtained in citrus/sweet potato, citrus/large green, control plot and citrus/cucumber (28.67, 45.00, 50.00 and 76.33 m-2 respectively) than in citrus/groundnut plot (143.00 m-2). Similarly, significantly lower grass weed densities were produced in citrus/Mucuna and citrus/sweet potato (0.33 m-2 each) plots than the control plot (11.33 m-2). Whereas citrus/corchorus plot produced significantly lower broadleaf weed dry weight (37.59 g m-2) than citrus/Mucuna plot (126.47 g m-2) at 3WAP, citrus/large green plot (16.15 g m-2) and citrus/groundnut plot (123.25 g m-2) followed the same trend at 6 WAP. Sedges dry weights were less than 7 g m-2 in all the plots compared with control plot.

Highlights

Citrus as a fruit crop acts as a rich source of vitamin C and other essential nutrients required by human body and this has necessitated its wide cultivation in Nigeria (Adewale et al, 1996), Brazil, USA and other countries (Florida Citrus Agriculture, 2004)
Maize and M. pruriens were planted at a spacing of 90 cm × 45 cm each, cucumber, groundnut and sweet potato at 60 cm × 30 cm each while Corchorus, large green, and grain amaranth were drilled at 30 cm apart each at a
Weed relative frequencies (%) in young citrus trees intercropped with arable crops 6 WAP at National Horticultural Research Institute (NIHORT), Ibadan, Nigeria

Summary

Introduction

Citrus as a fruit crop acts as a rich source of vitamin C and other essential nutrients required by human body and this has necessitated its wide cultivation in Nigeria (Adewale et al, 1996), Brazil, USA and other countries (Florida Citrus Agriculture, 2004). The citrus trees take longer time to produce fruit and so short duration crops like chilli, amaranth (Aiyelaagbe, 2001), turmeric, pepper, ginger and basil (Oyedele et al, 2011) can provide ready cash flow. In the southern part of Nigeria, a number of crops like cowpea, okra, water melon, pepper, amaranth and maize have been found to be compatible with citrus intercrop (NIHORT, 2000). Depending on the crops intercropped, competition for water, light and nutrients may result in lower yields. Lower weed biomass has been reported in intercropping systems where a main crop was inter-sown with a “smother” crop species ( Jodha, 1979). Greater crop yield and less weed growth can be obtained more frequently in intercrops than in sole crops.

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