How Does Maize-Cowpea Intercropping Maximize Land Use and Economic Return? A Field Trial in Bangladesh

Abstract

Cultivating multiple crops together can provide numerous benefits, including improved soil health and crop yield. The objective of our study was to determine the optimum planting techniques in intercropping systems, and to maximize their benefits by mitigating competition for resources such as land, space, light interception, and nutrition. The performance of successively planted maize (Zea mays L.) grown with cowpea (Vigna unguiculata L.) was evaluated with a field trial in Bangladesh. The treatments in our study were: (a) sole maize, (b) sole cowpea, (c) crops sown simultaneously, and (d) crops sown with different time lags (1, 2, and 3 weeks) between the maize-sowing and cowpea-sowing dates. Data on the crops’ physiological parameters were recorded. These included light interception, leaf area index (LAI), Soil Plant Analysis Development (SPAD), harvest index, and yield. Simultaneously, canopy coverage was measured using camera-based photo analysis. In addition, an economic analysis of intercropping maize with soybean or cowpea was conducted using gross margin analysis and benefit-cost ratio. In our results, the below-canopy photosynthetically active radiation (PAR) was significantly higher in intercropping treatments when maize was sown three weeks after cowpea. In contrast, the LAI value of the maize and cowpea was significantly greater when sown on the same day than in other intercropping treatments. As a result, the maize yield reduced when intercropped with cowpea. This reduction maximized when both species were sown simultaneously due to higher competition for resources, including nutrients and light. Intercropping was more beneficial in terms of land equivalent ratio than both sole cropping of maize and cowpea, especially when maize was planted three weeks later. However, this benefit was not retained when calculated as maize equivalent yield since the contribution of cowpea was small in the overall maize yield, suggesting the importance of the relative economic value of the component species. Among all treatments, the lowest maize equivalent yield (6.03 ± 0.14 t ha−1) was obtained from sole cowpea, and the largest land equivalent ratio (1.67 ± 0.05) was obtained from intercropping with maize sown three weeks after cowpea. This treatment provided a net income of USD 786.32 ± 25.08 ha−1. This study has shown that together, maize–cowpea intercropping with a temporal niche difference of three weeks may be a better option for sustainable crop production in Bangladesh, maximizing land use. However, it may not provide a significantly greater maize equivalent yield and economic return.

Intercropped Maize and Cowpea Increased the Land Equivalent Ratio and Enhanced Crop Access to More Nitrogen and Phosphorus Compared to Cultivation as Sole Crops

“…Although legumes generally have taprooted systems along with N-fixing nodules that provide access to atmospheric N [12,13], under the agroecological conditions of this study, the characteristics of maize seem to confer a competitive advantage over cowpea when grown in intercropping. Other studies have also reported a reduction in the productive performance of cowpea when intercropped with maize, compared to sole cropping [24,36]. This may probably occur because cowpea plants, being shorter, are shaded by the maize and have less access to light.…”

“…Growing two plant species in the same space at the same time leads to competition for resources, particularly for light, water, and minerals [20,21,24]. Maize is a tropical grass with C4 metabolism, and its tall growth provides excellent exposure to solar radiation, which can result in high photosynthesis rates [37,38].…”

“…Estimating the land equivalent ratio (LER) in intercrops also leads to an understanding of the interactions affecting yields. LER is defined as the relative land area required as sole crops to produce the same yields as intercropping [20] and has been successively used in many studies, providing valuable information for the management of intercrops [14,18,[22][23][24].…”

Maximizing Land Use Efficiency by Intercropping Some Summer Forage Crops With Maize

“…In this respect, other researchers came with the same result and found that intercropping maize with other crops caused a reduction in each of no. of cobs/plant (Ijoyah et al,2015), no .of grains/ear (Dusa and Roman, 2010;Abd El-Zaher andIsmail, 2014 andSuhi et al, 2022), 100-grain weight (El-Ghobashy et al, 2018), ear weight (Abou El-Enin et al, 2023) and grain yield/plant (Mahdy, 2018 b) compared to maize sole cropping. Moreover, it can be observed generally that intercropping sudan grass with maize produced the highest reduction in grain maize yield and its attributes compared to the other tested forage crops.…”

Application of Crop Modeling in Multi-Cropping Systems for Maximize Production and Build Resilient Ecosystem Services

“…A landscape generator typically considers different agricultural land use systems including natural, semi-natural habitats, cropland, and landscape elements. Maize-cowpea intercropping with a temporal niche difference is a better option for sustainable crop production and maximizing land use [94]. Meixiu et al [95] showed that intercropping could be used to obtain more yield on less land with less water by developing and application of dynamic process-based modeling taking into account the acquisition of light and water by the component species.…”