| Autor: |
Panhwar, Q. A., Shamshuddin, J., Naher, U. A., Razi, I. Mohd, Yusoff, M. A., Ali, A., Depar, N. |
| Předmět: |
|
| Zdroj: |
Malaysian Journal of Soil Science; Dec2023, Vol. 27, p70-79, 10p |
| Abstrakt: |
Low pH acid sulfate soils are usually nutrient-deficient. They contain toxic metals that affect rice plants negatively. A field experiment was carried out to alleviate acidity in an acid sulfate soil for rice cultivation. In the study, rice-seedlings (variety MR219) were planted in the experimental plots treated with bio-fertilizer, ground magnesium limestone (GML) and biochar, either alone or in combination. pH of the untreated topsoil was 3.56, while the exchangeable calcium and magnesium in the topsoil was 4.13 cmolckg-1, below the requirement to sustain growth and/or production of rice. Addition of bio-fertilizer slightly increased soil pH. The highest soil pH of 5.34 was observed in the plot treated with bio-fertilizer plus GML. Iron in the control plot was believed to exist in the form of Fe3+ (pKa 3). Due to treatment with bio-fertilizer plus GML or biochar, soil pH increased from 3.56 to a level >5. As the soil pH was approaching 4.58 (i.e., the pKa of Fe2+), Fe3+ was slowly converted to Fe2+ . The form of iron causing toxicity to rice in the treated plots was most likely to be Fe2+, rather than Fe3+ . At soil pH >5, both Fe2+ and Al3+ (the pKa is 5) were precipitated as inert hydroxides, thus, no longer causing toxicity to the rice plants. Beneficial microbes present in the bio-fertilizer helped produce growth hormones and organic acids that eventually increased nutrient uptake by rice which in turn enhanced its growth. The organic acids fixed some Fe2+ and Al3+ in the soil via chelation process. This phenomenon further reduced their toxicity to the rice plants. Application of bio-fertilizer plus GML or biochar improved soil fertility that resulted in higher rice yield. This notion is supported by the enhancement of the rice yield parameters, i.e., plant height (92.21 cm), tiller numbers (6), leaf chlorophyll content (38.14) and the number of filled grains. The use of bio-fertilizer plus GML or biochar is recommended for rice cultivation on acid sulfate soils in order to increase rice self-sufficiency level (SSL) and sustain food security in country in the long run. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
|
