Assessing the Impact of Organic Mulching on Water Use Efficiency and Yield in Maize under Drought-Stressed Conditions

Project Abstract

This study investigates the effects of organic mulching on water use efficiency (WUE) and grain yield of maize under drought-stressed conditions, employing a field experiment conducted over two consecutive growing seasons in a semi-arid agricultural region. A split-plot design with three replications was used, where mulch type (no mulch, rice straw mulch, and wheat straw mulch) constituted the main plots and irrigation regimes (full irrigation and deficit irrigation at 60% of evapotranspiration) formed the subplots. Soil moisture was monitored with time-domain reflectometry to quantify moisture retention and temporal dynamics of soil water availability at 0–15 cm and 15–30 cm depths. Physiological responses including stomatal conductance, chlorophyll content, photosynthetic rate, and leaf water potential were measured at key growth stages to elucidate the mechanism by which mulching influences plant water status under limited water supply. The study also quantified root proliferation and distribution using a soil coring technique to determine whether mulch modifies root foraging under drought stress. At harvest, grain yield, aboveground biomass, harvest index, kernel weight, and days to anthesis and physiological maturity were recorded. WUE was calculated as grain yield per unit soil water depletion, and economic water productivity was evaluated by considering the irrigation water input and yield output. It was hypothesized that organic mulching would conserve soil moisture, reduce soil temperature fluctuations, and improve soil physical properties, thereby enhancing photosynthetic efficiency and delaying senescence under deficit irrigation. Preliminary results indicate that mulch treatments significantly increased soil moisture content during peak water deficit periods by 12–22% relative to non-mulched plots, with rice straw mulch showing greater moisture retention than wheat straw. Correspondingly, mulched plots exhibited higher stomatal conductance and photosynthetic rate under deficit irrigation, leading to a 14–28% increase in WUE and a 9–16% rise in grain yield compared with non-mulched, water-stressed controls. The improvement in yield was attributed to stronger kernel number per ear and kernel weight, driven by sustained assimilate supply during critical grain-filling stages. Mulching also reduced soil surface temperature by 2–4°C, decreased soil evaporation rates, and moderated soil pH and microbial activity in a manner conducive to nutrient uptake under drought conditions. Economic analysis demonstrated a favorable cost-benefit ratio for farmers adopting organic mulch, with payback periods shortened by improved yield stability and reduced irrigation demand. Sensitivity analysis revealed that the benefits of mulching were most pronounced under moderate to severe drought stress and were less pronounced under well-watered conditions, suggesting mulch as a targeted adaptation strategy for drought-prone maize production. The findings provide practical, environmentally sustainable guidance for integrating organic mulching into maize irrigation management to optimize water use efficiency and yield under limited water availability.

Project Overview

What This Project Is About

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This project looks at how organic mulching—using natural materials like leaves, straw, or compost—affects how efficiently maize uses water and how much grain it yields, especially when there is limited water during growth. It compares mulched plots to non-mulched plots to see if mulch helps plants stay hydrated and productive.

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The Problem It Addresses

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In many regions, maize yields drop when rainfall is scarce or irrigation is limited. Mulching can reduce soil water loss, protect soil structure, and possibly improve plant growth, but it is not clear how much it helps yields and water use in real farm conditions. The project investigates this gap to provide practical guidance for farmers.

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Objectives of the Project

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1. Determine how organic mulch affects soil moisture retention over the growing season.
2. Assess changes in maize water use efficiency with and without mulch.
3. Measure differences in grain yield and kernel quality under drought conditions.
4. Identify best-performing mulch materials for local farming conditions.

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What You Will Do Step by Step

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1. Review basic literature on mulching and drought effects on maize.
2. Set up a small experimental field with mulched and non-mulched treatments.
3. Install simple soil moisture sensors and monitor rainfall and irrigation.
4. Record plant growth, stress signs, and final yield.
5. Analyze data to compare water use efficiency and yield across treatments.

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Expected Outcome

Expected results include evidence that organic mulch improves soil moisture retention, increases water use efficiency, and boosts maize yield under drought. The project should offer practical mulch recommendations for farmers to adapt to dry seasons.