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Opportunities to close wheat yield gaps in Nepal’s Terai: Insights from field surveys, on-farm experiments, and simulation modeling

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Title Opportunities to close wheat yield gaps in Nepal’s Terai: Insights from field surveys, on-farm experiments, and simulation modeling
 
Creator Devkota Wasti, Mina
 
Contributor Devkota, Krishna
Paudel, Gokul Prasad
Krupnik, Timothy
James McDonald, Andrew
 
Subject random forest
meta-analysis
good agronomic practices
apsim next generation
genotype x environment x management
 
Description CONTEXT
Wheat (Triticum aestivum) is among the most important staple food crops in the lowland Terai region of Nepal. However, national production has not matched the increasing demand. From a South Asian regional perspective, average productivity is low with high spatial and temporal variability.

OBJECTIVES
This study determines entry points for closing yield gaps using multiple diagnostic approaches, i.e., field surveys, on-farm experiments, and simulation models across different wheat production environments in the Terai region of Nepal.

METHODOLOGY
Yield and production practice data were collected from 1745 wheat farmers' fields and analysed in tandem with over 100 on-farm experiments. These were complemented by long-term simulation modeling using the APSIM Next Generation to assess system production behavior over a range of climate years.

RESULTS AND DISCUSSION
On-farm survey data suggests that yield and profit gaps under farmers' management (difference between the most productive (top 10th decile) and average wheat fields) were 1.60 t ha−1 and 348 USD ha−1 in the Terai region. The potential yield gap (difference between simulated potential yield and surveyed population mean) estimated was 4.63 t ha−1, suggesting ample room for growth even for the highest-yielding fields. Machine learning diagnostics of survey data, and on-farm trials identified nitrogen rate, irrigation management, terminal heat stress, use of improved varieties, seeding date, seeding method, and seeding rate as the principal agronomic drivers of wheat yield. While fields in the top 10th decile yield distribution had higher fertilizer use efficiencies and irrigation and seeding rates with similar overall production costs as average-yielding farmers. Our results suggest a complementary set of agronomic interventions to increase wheat productivity among lower-yielding farms in the Terai including advancing the time of seeding by 7–10 days on average, increasing nitrogen fertilizer by 20 kg ha−1, and alleviating water stress by applying two additional irrigations.

SIGNIFICANCE
Although wheat yields in the Terai are among the lowest in the region, biophysical production potential is high and remains largely untapped due to sub-optimal agronomic management practices rather than intrinsic agroecological factors. Data from this study suggests that incremental changes in these practices may result in substantial gains in productivity and profitability.
 
Date 2023-11-30T19:14:01Z
2023-11-30T19:14:01Z
 
Type Journal Article
 
Identifier https://ars.els-cdn.com/content/image/1-s2.0-S0308521X23002093-mmc1.docx
https://mel.cgiar.org/reporting/download/hash/8f3cd1c735b9b0ac1a81bc4ad20da708
Mina Devkota Wasti, Krishna Devkota, Gokul Prasad Paudel, Timothy Krupnik, Andrew James McDonald. (1/1/2024). Opportunities to close wheat yield gaps in Nepal’s Terai: Insights from field surveys, on-farm experiments, and simulation modeling. Agricultural Systems, 213.
https://hdl.handle.net/20.500.11766/68829
Open access
 
Language en
 
Rights CC-BY-4.0
 
Format PDF
 
Publisher Elsevier Masson
 
Source Agricultural Systems;213,(2023)