DefinePK

Research Objective

To assess the effects of integrated use of organic manures and chemical fertilizers on rice and wheat yields, nutrient contents, and characteristics of recently reclaimed saline sodic soil.

Methodology

A field study was conducted on a recently reclaimed saline sodic soil. The soil was reclaimed using 100% of the required gypsum. Six different organic manures (wheat straw, sesbania green manure, press mud, FYM, poultry manure, and eucalyptus leaves litter) were applied at a rate of 20 t.ha-1, combined with 75% of the recommended dose of NPK. A control treatment received only 75% of the recommended NPK. The experiment followed a randomized complete block design with three replications. Rice was transplanted one month after manure application. After the rice harvest, wheat was grown in the same layout. Soil and crop samples were analyzed for various parameters including yield, nutrient content (N, P, K), pHs, ECe, and SAR.

Methodology Flowchart

                        graph TD
    A[Reclaim Saline Sodic Soil with Gypsum] --> B[Apply Organic Manures and 75% NPK];
    B --> C[Transplant Rice Crop];
    C --> D[Collect Rice Yield and Soil Samples];
    D --> E[Analyze Rice Yield and Soil Properties];
    E --> F[Grow Wheat Crop - Residual Effect];
    F --> G[Collect Wheat Yield and Soil Samples];
    G --> H[Analyze Wheat Yield and Soil Properties];
    H --> I[Draw Conclusions on Integrated Nutrient Management];                    

Discussion

The study highlights the benefits of integrating organic manures with chemical fertilizers for improving crop yields and soil health in reclaimed saline sodic soils. Organic manures contribute essential nutrients, improve soil structure, and enhance nutrient availability. The decomposition of organic matter releases organic acids, which can help in reclaiming sodic soils by activating native CaCO3 and converting it to CaSO4. The residual effects of organic manures demonstrate their long-term benefits for subsequent crops. The integrated approach is crucial for sustainable agriculture in salt-affected areas.

Key Findings

- All organic manures enhanced rice yield (paddy and straw) compared to the control. Poultry manure, FYM, and sesbania green manuring resulted in the highest rice yields.
- Press mud treatment led to the highest phosphorus content in rice paddy and straw. Wheat straw treatment resulted in the highest potassium content.
- After rice harvest, poultry dung treatment showed the lowest ECe. Press mud and sesbania treatments showed a drop in SAR, while FYM remained comparable to poultry manure.
- Wheat straw and poultry manure treatments showed the highest K content in rice paddy and straw, respectively.
- Residual effects of organic manures on wheat showed that poultry manure, press mud, and FYM treatments resulted in the highest wheat grain and straw yields.
- Integrated use of organic manures and chemical fertilizers led to a decrease in soil salinity/sodicity parameters (pHs, ECe, and SAR) after both rice and wheat harvests.
- The highest total N and available P in the soil after rice harvest were observed with FYM and poultry manure combined with chemical fertilizer.
- After wheat harvest, poultry manure and press mud treatments showed the highest total N and available P in the soil.

Conclusion

The integrated use of organic manures (poultry manure, FYM, press mud, sesbania green manuring, wheat straw, and litter) with NPK fertilizers significantly enhances and sustains rice and wheat yields in reclaimed saline sodic soils. This approach also improves soil fertility and ameliorates salinity and sodicity characteristics, offering a sustainable solution for agricultural productivity in such challenging environments.

Fact Check

- The study was conducted in 2020-21.
- The initial soil characteristics were ECe 8.50 dS m-1, pHs 8.90, and gypsum requirement 4.12 tons acre-1.
- Organic manures were applied at 20 t.ha-1.

Mind Map