SAINS TANAH - Journal of Soil Science and Agroclimatology
Vol 21, No 2 (2024): December

The concept of bio-economic mulching in droughty tropical agroecosystems and its trans-season effects on soil hydro-thermal regime and okra performance

Okorie, Benedict Odinaka (Unknown)
Obi, Justina O. (Unknown)
Chioke, Geraldine U. (Unknown)
Obalum, Sunday E. (Unknown)
Onah, Chinaza J. (Unknown)
Nnadi, Adaobi L. (Unknown)
Igwe, Charles A. (Unknown)
Obi, Martin E. (Unknown)



Article Info

Publish Date
26 Nov 2024

Abstract

Mulching is an effective soil-water conservation technique in high-evaporative-demand tropical climates. Because of the drawbacks in bulk application of organic mulches, we introduce the concept of bio-economic mulching (BEM), a one-time low-rate application of organic mulch to improve soil productivity while sustaining economic viability. The study evaluated the effects of BEM (dry-grass mulching at 0, 2, 4, and 6 t ha–1) on soil hydrothermal properties of sandy-loam Ultisols using okra growth during 4–9 weeks after sowing in successive rainy-to-dry/partially rainfed season (PRS) and rainy/completely rainfed season (CRS). During the PRS, soil volumetric moisture content (q) increased (10.02%–25.50%), but soil temperature decreased (37.67–26.67°C) as BEM rate increased. A similar q trend (8.71%–18.37%) occurred during the CRS. Soil thermal conductivity (0.78to 4.88 W m–1 K–1), thermal diffusivity (3.95 × 10–7 to 35.97 × 10–7 m2 s–1), and heat flux (15.00 to 85.56 W m–2) generally decreased as q increased with BEM application rate particularly during the PRS; the reverse prevailed for volumetric heat capacity (1.33 × 106 to 2.25 × 106 J m–3 K–1). Okra plant height differed (BEM-6 > BEM-4 > BEM-2/BEM-0) in the PRS, but BEM-6 and BEM-4 gave the tallest and shortest plants, respectively in the CRS. Fruit yield was 1.8- and 9.5-fold higher in BEM-6 than BEM-4 in PRS and CRS, respectively. Mulch treatment-induced temporal variations in soil q influenced okra performance indices of plant height (r2 = 0.85) and total fresh fruit yield (r2 = 0.69). In droughty tropical environments, BEM implementation at 6 t ha−1 could engender soil hydrothermal regime favoring vegetable production beyond the ‘drier’ first season and even more pronouncedly in the second season.

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