Cropping system diversification for food production in Mindanao rubber plantations: a rice cultivar mixture and rice intercropped with mungbean.

Rosa Fe Hondrade,Christopher C Mundt,Jo-Anne Lynne Joy E Duque,Lianqing Zheng,Edwin Hondrade,Francisco Elazegui,Karen A Garrett,Casiana M Vera Cruz

doi:10.7717/peerj.2975

Abstract

Including food production in non-food systems, such as rubber plantations and biofuel or bioenergy crops, may contribute to household food security. We evaluated the potential for planting rice, mungbean, rice cultivar mixtures, and rice intercropped with mungbean in young rubber plantations in experiments in the Arakan Valley of Mindanao in the Philippines. Rice mixtures consisted of two- or three-row strips of cultivar Dinorado, a cultivar with higher value but lower yield, and high-yielding cultivar UPL Ri-5. Rice and mungbean intercropping treatments consisted of different combinations of two- or three-row strips of rice and mungbean. We used generalized linear mixed models to evaluate the yield of each crop alone and in the mixture or intercropping treatments. We also evaluated a land equivalent ratio for yield, along with weed biomass (where Ageratum conyzoides was particularly abundant), the severity of disease caused by Magnaporthe oryzae and Cochliobolus miyabeanus, and rice bug (Leptocorisa acuta) abundance. We analyzed the yield ranking of each cropping system across site-year combinations to determine mean relative performance and yield stability. When weighted by their relative economic value, UPL Ri-5 had the highest mean performance, but with decreasing performance in low-yielding environments. A rice and mungbean intercropping system had the second highest performance, tied with high-value Dinorado but without decreasing relative performance in low-yielding environments. Rice and mungbean intercropped with rubber have been adopted by farmers in the Arakan Valley.

Highlights

The spread of agricultural non-food systems, such as rubber plantations, is a major factor for smallholder farmers and farm laborers, who often must navigate potential shifts from traditional swidden systems (Fox & Castella, 2013; Josol & Montefrio, 2013; Li et al, 2014; Manivong & Cramb, 2008; Mertz et al, 2013; Montefrio & Sonnenfeld, 2013; Van Vliet et al, 2012; Vongvisouk et al, 2014)
Rice yields per row were greater in intercropping systems than in monoculture in some cases, yields varied widely within and among years (Fig. 2 and Tables 2–5)
There was a tendency for rice yields to be higher when rice made up a smaller proportion of the intercrop rows

Summary

Introduction

The spread of agricultural non-food systems, such as rubber plantations, is a major factor for smallholder farmers and farm laborers, who often must navigate potential shifts from traditional swidden systems (Fox & Castella, 2013; Josol & Montefrio, 2013; Li et al, 2014; Manivong & Cramb, 2008; Mertz et al, 2013; Montefrio & Sonnenfeld, 2013; Van Vliet et al, 2012; Vongvisouk et al, 2014). The cleared land between young trees is wasted from an economic standpoint, and may be subject to erosion, if it is not planted with other crops. The use of intercropping of food crops in tree plantations has the potential to address both of these problems. Rubber trees may be intercropped with a range of other plant species, including food crops and tea, cocoa, coffee, rattan, fruit trees, and cinnamon (Jessy, Joseph & George, in press; Pathiratna & Perera, 2006; Penot & Ollivier, 2009; Wu, Liu & Chen, 2016). Rubber intercropping with a crop like banana, before latex is produced, may even improve rubber production (Rodrigo et al, 2005). In Kerala, India, adoption of intercropping of rubber with pineapple, banana, and cassava was reported as most common (Rajasekharan & Veeraputhran, 2002)

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