Agri-SCHOLAR: Simulation-Grounded In-Season Rolling Advisories for Agricultural Crops Using LLM-Bounded Optimization
Authors: Geetha Charan, Vedant Balasubramaniam, Manojkumar Patil, V. Priyanka, Kodur Sai Vinay Sathvik, Rohit P Suresh, Mohammad Sufyan Azam, Y. Narahari
Organizations: Indian Institute of Science, Bengaluru, India · University of Michigan, Ann Arbor, USA
Existing agricultural advisories to farmers suffer from several limitations: (a) remain largely expert-driven, (b) do not adequately account for in-season weather, and (c) do not scale to individual farms. In this paper, our objective is to close these gaps by developing Agri-SCHOLAR (Simulation-Grounded Crop Harvest Optimization with LLM-Guided In-Season Advisory Rollouts). Agri-SCHOLAR is a rolling, in-season advisory framework that issues, at intervals of every few days or every week, a personalized advisory using the following information: soil and crop properties, observed weather to date, short-range forecast of weather, and a season extrapolation of weather based on historical analogs. The novelty and depth of Agri-SCHOLAR lies in each advisory being produced by a closed-loop system which couples multiple LLM agents with a powerful crop simulator (such as APSIM in our case). The simulator crucially serves as an evaluation oracle. In Agri-SCHOLAR, the LLM agents propose agronomically sound and feasible bounds on actionable parameters and an optimizer searches within those bounds against a multi-objective reward spanning yield, resource utilization, and economic feasibility. We conduct a detailed 11-year analysis of the maize crop in two selected locations of South Asia and show that Agri-SCHOLAR consistently outperforms the region's standard packages of practice and satisfactorily addresses the limitations of existing agricultural advisories.
Figures & tables
Figure 1: Agri-SCHOLAR architecture.
Symbol
Meaning
Source
Y
Grain yield
APSIM: [Maize].Grain.Wt
SWt , DULt , SATt
Soil water, drained upper limit, and saturation of the profile on day t
APSIM: [Soil].Physical.[SWmm/DULmm/SATmm]
Ndemand
Crop nitrogen demand, summed over leaf, stem, root, and grain organs
APSIM: sum of NDemand.Total over the organs
Dcml
Cumulative deep drainage
APSIM: [WaterBalance].Drainage
LNO3 , LNH4
Cumulative nitrate and ammonium leaching
APSIM: [WaterBalance].[LeachNO3/LeachNH4]
SOC0 , SOCH
Soil organic carbon (SOC) at the start and end of the horizon
APSIM: [Soil].Organic.Carbon
Table 1: Quantities used in the reward and their sources.
Figure 2: Grain yield per season under PoP baseline and Agri-SCHOLAR.
Figure 3: Net profit per season under PoP baseline and Agri-SCHOLAR (irrigated region).
Region
Method
Yield(kg/ha)
Profit($/ha)
Prod. cost
Sust. penalty
Irrigated
PoP
6,477.55
5,959.33
284.02
495.33
Agri-SCHOLAR
7,461.00
7,025.09
469.68
267.05
Rainfed
PoP
5,909.36
5715.15
149.63
282.81
Agri-SCHOLAR
7,234.55
7,037.19
214.09
274.95
Table 2: Mean yield, net profit, production cost, and sustainability penalty over 11 seasons. Monetary values are in PPP-adjusted $/ha. Best value per column and region in bold (highest for yield and profit, lowest for cost and penalty).
Figure 4: Drainage and Leaching per season (irrigated region).
Figure 6: Case study for irrigated region, 2023 season. (a) UreaN applied per week (b) Irrigation per week (c) Projected Yield
Variant
Yield (kg/ha)
Profit ($/ha)
Prod. cost
Sust. penalty
Agri-SCHOLAR
7,461.00
7,025.09
469.68
267.05
Loose bounds
7,614.82
7,199.86
401.24
320.73
± 1,785.82
± 1,823.07
± 61.40
± 107.33
No bounds
7,082.64
1,682.69
4,451.40
1,234.11
± 2,153.72
± 3,117.25
± 2,521.46
± 1,503.77
Table 3: ABA ablation: irrigated region, mean over 11 seasons.
Parameter
Notation
LCU
$
Source/Basis
Grain price (per kg)
pg
20.90
1.04
Support price [ 28 ]
UreaN (per kg N)
p1F
13.04
0.65
Retail price [ 29 ]
DAP (per kg)
p2F
27.00
1.34
Retail price [ 29 ]
Mulch (per kg)
pM
2.00
0.10
Residue and fodder prices [ 30 ]
Water (per mm)
pw
2.50
0.12
Irrigation charges [ 31 , 32 ]
Labour (per operation)
pL
350.00
17.42
Rural wage [ 33 ]
Table 4: Cost and penalty parameters used in Optimization Agent (OA).