This study evaluated the agronomic performance of Terreplenish, a microbial soil amendment, under irrigated rice production at the Ashiaman Irrigation Scheme in Southern Ghana. The objective was to assess the effect of Terreplenish on rice growth, yield components, grain filling, and overall productivity under coastal savannah irrigated conditions.

Three nutrient management treatments were compared:

Control: 100% recommended inorganic fertilizer
Split application of 50% Terreplenish Treatment: 50% Terreplenish + 50% fertilizer, with an additional 50% Terreplenish application at the flowering stage
100% Terreplenish Treatment: 100% Terreplenish + 50% fertilizer

The results demonstrated that Terreplenish significantly enhanced rice growth and yield performance relative to the control treatment. Grain yield increased from 7.92 t/ha under the control to 8.53 t/ha under the 50% Terreplenish treatment and 8.86 t/ha under the 100% Terreplenish treatment, corresponding to yield increases of 7.7% and 11.9%, respectively.

The observed yield improvements were primarily associated with enhanced reproductive performance and improved nutrient utilization efficiency. Terreplenish treatments increased spikelet fertility, reduced the proportion of unfilled grains, and improved grain filling. The highest grain filling percentage (93.5%) was recorded under the 100% Terreplenish treatment, indicating superior assimilate partitioning during the reproductive stage.

Growth-stage assessments further revealed that the 50% Terreplenish treatment promoted vigorous early tillering and vegetative development, while the 100% Terreplenish treatment produced the strongest reproductive response, resulting in higher filled spikelets and superior grain yield.

Overall, the findings confirm that Terreplenish has substantial agronomic potential for sustainable irrigated rice production in Southern Ghana. The technology improved crop productivity while reducing dependence on synthetic fertilizer inputs, demonstrating its suitability as an environmentally sustainable nutrient management strategy for intensified rice cultivation systems.

2. Introduction

Rice production in Southern Ghana faces challenges including declining soil fertility, rising input costs, and inefficient nutrient utilization. While synthetic fertilizers improve short-term productivity, they do not sustain soil biological health.

Terreplenish, a microbial consortium, improves: soil biological activity, nutrient cycling, root development and stress tolerance. This study evaluates its performance under irrigated coastal savannah conditions at Ashiaman.

3. Objectives

General Objective

To evaluate the effect of Terreplenish on rice growth and yield under irrigated conditions.

Specific Objectives

Assess plant growth (height, tillering, vigor)
Evaluate yield and yield components
Analyze grain filling efficiency
Determine optimal application rate

4. Materials and Methods

4.1 Study Area

The field experiment was conducted at the Ashiaman Irrigation Scheme, specifically at Lateral 4, located within the coastal savannah agroecological zone of Southern Ghana. The area is characterized by relatively high temperatures, moderate humidity, and irrigated lowland conditions suitable for year-round rice cultivation. The irrigation scheme provides controlled water management, enabling uniform crop establishment and minimizing moisture stress during crop growth and development.

4.2 Crop Establishment and Growth Timeline

The rice crop was established during the 2025/2026 irrigated production season. Seeds were sown in a nursery on 24 November 2025 and transplanted into the main field between 22 and 24 December 2025, corresponding to 30 days after sowing (DAS). Crop growth and development were monitored throughout the season under irrigated conditions.

Key crop growth stages recorded during the study included:

Nursery establishment: 24 November 2025
Transplanting: 22–24 December 2025
First growth observation: 6 February 2026 (74 DAS)
Flowering stage: 5 March 2026 (101 DAS)
Harvesting: 7 April 2026 (134 DAS)

The total crop duration was 134 days, encompassing the vegetative, reproductive, and maturity phases of rice development.

4.3 Crop Details

The rice variety used for the study was Legon 1, a widely cultivated improved variety adapted to irrigated lowland conditions in Ghana. Healthy seedlings were raised under nursery conditions before transplanting into puddled and leveled experimental plots.

4.4 Experimental Design and Treatments

The experiment was laid out using a Randomized Complete Block Design (RCBD) with two replications to minimize field variability and improve treatment comparison accuracy.

Three nutrient management treatments were evaluated:

TreatmentDescription

T1 - Control (100% recommended inorganic fertilizer)

T2 - Split Terreplenish: 50% Terreplenish + 50% fertilizer + 50% Terreplenish applied at flowering stage

T3 - 100% Terreplenish + 50% fertilizer

Terreplenish was evaluated as a microbial soil amendment aimed at improving nutrient availability, plant growth, and grain filling efficiency under irrigated rice production conditions.

The following is the description of the treatments and how it was implemented. The three separate plots consisted of as indicated above:

Control Plot - The control plot received the full rate of recommended fertilizer for rice in Ghana as indicated in the text).
Split Application Plot - Terreplenish at 50% rate (10L/ha) applied with 50% recommended rate of fertilizer to the soil at transplanting and 50% (10L/ha) was applied as a foliar spray by the internode elongation stage (early flowering stage).
Full Terreplenish Plot - Terreplenish at full standard rate (20L/ha, 20-1 dilution) applied with 50% of fertilizer to the soil.

Terreplenish was diluted to a 20-1 ratio with water.

4.5 Fertilizer Application

The recommended fertilizer regime applied in the study consisted of:

90 kg N ha⁻¹
45 kg P₂O₅ ha⁻¹
45 kg K₂O ha⁻¹

Fertilizer application was conducted according to the treatment specifications. In treatments containing Terreplenish, the microbial amendment was integrated with reduced inorganic fertilizer rates to assess its contribution to nutrient use efficiency and crop productivity.

4.6 Data Collection

Agronomic and yield-related data were collected at different growth stages to evaluate treatment performance. Parameters measured included:

Plant height (cm)
Number of tillers per hill
Days to flowering
Grain yield (t ha⁻¹)
Number of filled spikelets
Number of empty spikelets

Yield data were collected at harvest maturity and converted to tons per hectare (t ha⁻¹). Spikelet fertility and grain filling percentage were determined using filled and unfilled grain counts to assess reproductive efficiency under the different nutrient management treatments.

5. Environmental Conditions (Ashiaman- Southern Ghana)

(Based on typical coastal savannah conditions during the study period)

Irrigation ensured non-limiting water conditions

6. Results

6.1 Growth Parameters

Growth parameters were assessed at the vegetative, flowering, and harvest stages to determine the effect of Terreplenish on rice growth and tillering under Ashaiman conditions in Southern Ghana.

6.2 Vegetative Stage (74 DAS)

Table 1. Growth Parameters at Vegetative Stage (74 DAS)

At the vegetative stage, plant height ranged from 59.0 cm to 61.0 cm across treatments. The 100% Terreplenish treatment recorded the tallest plants (61.0 cm), while the 50% TP treatment recorded the shortest plants (59.0 cm).

Tiller production was highest under the 50% TP treatment (22.8 tillers), followed by the control (21.7 tillers), while the 100% TP treatment recorded slightly lower tiller numbers (21.05 tillers).

The results suggest that Terreplenish influenced early vegetative development and tillering dynamics, particularly under split application conditions.

6.3 Flowering Stage (101 DAS)

Table 2. Growth Parameters at Flowering Stage (101 DAS)

At the flowering stage, the control treatment recorded the tallest plants (95.66 cm), followed by the 100% TP treatment (90.0 cm), while the 50% TP treatment recorded the lowest plant height (83.66 cm).

Tiller numbers remained relatively similar across treatments; however, the 100% TP treatment produced the highest number of tillers (19.4 tillers), indicating sustained vegetative vigor during reproductive development.

The reduction in plant height observed in Terreplenish treatments may indicate improved assimilate partitioning toward reproductive growth rather than excessive vegetative elongation.

6.4 Harvest Stage (134 DAS)

Table 3. Tillering Performance at Harvest Stage (134 DAS)

Treatment Total Tillers Effective Tillers

Control 18.5 16.2

50% TP 20.0 18.0

100% TP 17.0 15.9

At harvest, the 50% TP treatment recorded the highest number of total tillers (20.0) and effective tillers (18.0), indicating superior tiller survival and productivity.

The control treatment recorded 18.5 total tillers and 16.2 effective tillers, while the 100% TP treatment recorded the lowest tiller numbers at harvest.

The higher number of effective tillers observed under the 50% TP treatment suggests improved tiller retention and productive tiller formation, which may have contributed to enhanced grain production.

Overall Interpretation of Growth Parameters

The growth analysis indicates that Terreplenish influenced rice growth differently across developmental stages.

Key observations include:

Improved tillering during vegetative growth under the 50% TP treatment
Sustained tiller production at flowering under the 100% TP treatment
Higher effective tiller retention at harvest under the 50% TP treatment

Although plant height was not consistently increased by Terreplenish application, the treatments improved physiological efficiency and productive tiller development. This suggests that Terreplenish enhanced crop performance through improved growth balance and reproductive efficiency rather than excessive vegetative growth.

Table 4. Effect of Terreplenish treatments on Yield and Yield Components

Table and Graphical Analysis of Yield and Yield Components

Table 4 and Figure 1 present the effect of Terreplenish application on rice yield, biomass production, panicle length, filled spikelets, and empty spikelets under Ashaiman conditions in Southern Ghana.

Yield Performance

Grain yield increased progressively across treatments with increasing Terreplenish application. The control treatment recorded the lowest yield of 7.92 t ha⁻¹, while the Split Terreplenish treatment produced 8.53 t ha⁻¹, representing a 7.7% increase over the control. The 100% Terreplenish treatment recorded the highest yield of 8.86 t ha⁻¹, corresponding to an 11.9% increase compared with the control.

The graphical trend demonstrates a clear positive response of rice productivity to Terreplenish application.

Biomass Production

Biomass accumulation followed a similar trend to grain yield. Plant biomass increased from 791.5 g m⁻² in the control to 853 g m⁻² under the Split Terreplenish treatment and further increased to 886 g m⁻² under the 100% Terreplenish treatment.

The increase in biomass indicates enhanced vegetative growth and improved crop vigor under Terreplenish application.

Panicle Length

Panicle length showed a slight decline with increasing Terreplenish rates. The control treatment recorded the highest panicle length (26.0 cm), followed closely by the Split Terreplenish treatment (25.9 cm) and the 100% Terreplenish treatment (25.6 cm).

Despite the slight reduction in panicle length, grain yield increased substantially across treatments. This indicates that yield improvement was not associated with panicle size, but rather with reproductive efficiency and grain filling.

Filled Spikelets

The number of filled spikelets increased consistently with Terreplenish application. The control treatment recorded 158 filled spikelets per panicle, while the Split Terreplenish treatment recorded 167 spikelets, representing a 5.7% increase. The 100% Terreplenish treatment produced the highest number of filled spikelets (172 spikelets), corresponding to an 8.9% increase over the control.

This trend suggests that Terreplenish enhanced spikelet fertility and grain filling efficiency, which directly contributed to higher grain yield.

Empty Spikelets

Empty spikelets were reduced under Terreplenish treatments compared with the control. The control treatment recorded 2.6 empty spikelets, while the Split Terreplenish treatment showed the lowest value (2.2 spikelets). The 100% Terreplenish treatment recorded 2.4 empty spikelets, which remained lower than the control.

The reduction in empty spikelets indicates improved assimilate partitioning and reproductive success under Terreplenish application.

Figure 1. Effect of Terreplenish on grain yield, biomass production, panicle length, filled spikelets, and empty spikelets of rice under Ashaiman conditions in Southern Ghana.

6.3 Correlation Analysis

Analysis of variance revealed a highly significant effect of Terreplenish on grain yield (F = 142.12, p < 0.001). Correlation analysis showed a strong positive relationship between yield and filled spikelets, confirming that yield improvement was primarily driven by enhanced grain filling (Figure 2).

Yield vs Filled Spikelets showed a strong positive correlation (~ +0.99) while Yield vs Empty Spikelets indicated negative correlation (~ -0.60). This means that Yield increases as filled grains increase and Yield decreases as empty grains increase which Confirms that Grain filling is the primary driver of yield improvement and that yield is driven primarily by grain filling efficiency and not plant size.

7. Discussion

7.1 Growth Response

The results indicated 50% TP improved early tillering and 100% TP improved tiller retention and reproductive performance. From the graphical analysis the results clearly demonstrates that Terreplenish positively influenced rice productivity through improvements in Biomass accumulation, Spikelet fertility and grain filling efficiency.

The increase in yield was primarily associated with higher numbers of filled spikelets rather than changes in panicle length. This also mean that increased yield is linked to better assimilate partitioning and improved nutrient efficiency. This suggests that Terreplenish improved physiological efficiency as well as good root-soil interaction during the reproductive stage of crop development.

The findings confirm that Terreplenish is effective in enhancing rice performance under the coastal savannah conditions of Ashaiman, Southern Ghana.

General Observations and Inspection by MoFA–PPRSD

Officials from the Plant Protection and Regulatory Services Directorate (PPRSD) conducted an inspection of the trial field during the panicle filling stage. The inspection team expressed satisfaction with the overall field performance, crop vigor, and management of the experimental plots.

The team indicated that the trial demonstrated promising results and advised that, upon submission of the final results and completion of the required evaluation procedures, the necessary regulatory and technical processes would be initiated in accordance with the Directorate’s guidelines and approval requirements.

Plate 3. Prof. Nkansah, Eric from MOFA PPRSD), Ms. Harriet and Mr. Amanor inspecting TP rice field at Ashiaman)

8. Conclusion

It can be concluded that Terreplenish significantly improves rice productivity in Southern Ghana by:

Enhancing grain filling
Increasing spikelet fertility
Improving yield efficiency

The 100% application rate produced the highest yield, while the 50% rate provides a cost-effective alternative.

9. Recomendations

Promote Terreplenish as part of integrated nutrient management systems

Encourage split application for improved grain filling efficiency

Expand field Demos across multiple ecological zones

10. References

FAO Rice Production Guidelines
MoFA Ghana Fertilizer Recommendations
IRRI Rice Production Manual
Soil Biology and Biochemistry Journal (Microbial Soil Amendments)
Ghana Meteorological Agency (Coastal Savannah Climate Data)

Apendix

OTHER FIELD OBSERVATIONS

Plate 4. PLANTS AT NEAR HARVESTING STAGE AFTER SHORT STORM

Apendix 1. Meteorological Data ( Ashiaman-Southern Ghana)

Interpretation

Trial occurred during dry-to-early rainy transition
Irrigation ensured no water stress
Yield response is therefore due to:
- Biological effects
- Nutrient efficiency
- Not rainfall variability

Apendix 2. Showing Terreplenish pictures at different growth stages

Hand Machine weeding in Terreplenish Rice Field

Terreplenish® Case Study : Ghana Rice Trials

Department of Crop Science

EVALUATION OF TERREPLENISH ON GROWTH, YIELD, AND SOIL HEALTH OF RICE (ORYZA SATIVA, LEGON 1) UNDER IRRIGATED CONDITIONS IN SOUTHERN GHANA (ASHIAMAN)

Conducted by: PROFESSOR GEORGE ODURO NKANSAH

Scientist:

Associate Professor (Agronomy/Horticulture) Department of Crop Science, University of Ghana-Legon.

4. Materials and Methods

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Terreplenish® Case Study :
Ghana Rice Trials

Associate Professor (Agronomy/Horticulture) Department of Crop Science,
University of Ghana-Legon.