Effects of Frequency of Irrigation on Dry-Season Furrow-Irrigated Maize and Peanut Production in the Rice-Growing Lowlands of the Lower Mekong Basin

Abstract

Incorporation of dry-season crops in the lowland production systems of the Lower Mekong Basin (LMB) may provide local smallholder farmers the opportunity to increase household cash income through diversification. However, water availability and lowland rice-growing soil characteristics often limit the yield potential of dry-season crops in rotation with wet-season rice. This work studied the effects of three frequencies of irrigation on the crop performance of dry-season furrow-irrigated maize (Zea mays Linnaeus) and peanut (Arachis hypogaea Linnaeus) grown on lowland rice-growing soils in terms of biomass, yield and water productivity (WP). In addition, the response of maize to two fertiliser rates was evaluated. The study was carried out in sites with typical lowland rice-growing soils located in Cambodia and Laos. Soil matric potential (Ψm) was monitored during the season at the centre of the beds and percentage of canopy cover, aboveground biomass (AGB), yield and WP were determined. The results showed that within the first weeks of furrow irrigation (~two weeks after emergence), Ψm dropped considerably (<−200 kPa) after all treatments at both sites, suggesting that water movement from the furrows to the centre of the beds was limited. Shorter frequency of irrigation led to significantly (p < 0.05) higher AGB and yield in maize but not in peanut. Fertiliser rates did not have a significant effect on maize. WP ranged from 0.84 kg m−3 to 1.42 kg m−3 for maize and from 0.27 kg m−3 to 0.49 kg m−3 for peanut with no significant differences among treatments. This work provides evidence of a lateral water movement limitation that is not well documented for the establishment of furrow-irrigated dry-season crop production in the lowlands of the LMB. Further research on methodologies that could help to overcome this limitation in these soils, such as the application of soil amendments or implementation of alternative irrigation systems, would be of great value.

Evaluating Strategies to Improve Water Availability and Lateral Root Growth of Plants Grown in the Rice-Growing Lowlands of the Lower Mekong Basin

“…Only for the period from 16 to 25 March 2017 when significant rainfall events occurred (471 mm) did soil water tension in all treatments return to values close to zero, indicative of a saturated soil. The lack of response of the sensors to irrigation highlights the severity of the soil physical constrains to lateral movement of water in these rice-growing soils reported in Ballester et al [6].…”

“…The study was conducted during the 2016/17 and 2017/18 dry seasons (from December to April) at the Phone Ngam Rice Research Centre, PNG (15 • 08 14.97 N, 105 • 47 13.78 E elevation 101 m), Pakse district, Champasak province in southern Laos and the Cambodian Agricultural Research and Development Institute, CARDI (11 • 28 34.27 N, 104 • 48 32.26 E elevation 17 m) Kambol district, Phnom Penh city in Cambodia (Figure 1). More details about the location of the sites can be found in Ballester et al (2019). Soil at these locations was a typical lowland rice-growing soil classified as Gleyic Acrisol based on the FAO/UNESCO classification [14].…”

“…At PNG, soil pH in 2016 pre-land preparation was 5.36 at 0-20 cm depth and averaged 5.91 in the 20-60 cm soil layer. More details regarding the physico-chemical properties of the soils at both sites can be found in Table 2 in Ballester et al [6]. One experiment was conducted per site in the 2016/17 dry season.…”

“…Lowland soils are typically sandy in texture and prone to hard setting, lacking in both organic matter and cation exchange capacity (CEC), acidic in the aerobic state and containing high levels of aluminum, particularly in the subsoil [4,5]. Recently, Ballester et al [6] highlighted the poor lateral movement of water in these soils, which leads to inadequate refilling of the root zone, a particular limitation for the establishment of furrow-irrigated dry-season crop production in the region.…”

“…The experiments were conducted on maize (Zea mays Linnaeus) in Cambodia and peanut (Arachis hypogaea Linnaeus) in Laos, which are two of the major non-rice crops grown in these countries [13]. Using agronomic management, the lateral water movement constraint reported in Ballester et al [6] may be overcome, which would provide major impact across large areas of south east Asia for increased dry season non-rice crop yields.…”