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Mobilization of phosphorus contributes to positive rotational effects of leguminous cover crops on maize grown on soils from northern Nigeria
Author(s) -
Kamh Mahmoud,
Abdou Mohamed,
Chude Victor,
Wiesler Franz,
Horst Walter J.
Publication year - 2002
Publication title -
journal of plant nutrition and soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.644
H-Index - 87
eISSN - 1522-2624
pISSN - 1436-8730
DOI - 10.1002/1522-2624(200210)165:5<566::aid-jpln566>3.0.co;2-o
Subject(s) - mobilization , agronomy , phosphorus , soil water , cover crop , environmental science , cover (algebra) , chemistry , biology , geography , soil science , archaeology , engineering , organic chemistry , mechanical engineering
Previous research has demonstrated a positive rotational effect of tropical leguminous cover crops on maize growth on a luvisol from Nigeria. This effect could not be explained by a better N supply. The objective of the present work was to further clarify whether improved P nutrition has been a contributing factor. Nine cover crops and maize were studied in nutrient solution‐culture with 1 and 20 μM P and with NO 3 ‐N as N source for root physiological parameters that may affect P mobilization. Zea mays, Lablab purpureus , and Centrosema pubescens responded to P deficiency by higher rates of proton excretion. Clitoria ternatea excreted OH — with only small differences due to P nutrition. At low P supply, Chamaecrista rotundifolia, Clitoria, and Centrosema had the highest exudation rates of organic acid anions, especially citrate and malate. A major difference between plant species was found in root‐surface acid phosphatase activity. Cajanus cajan expressed the highest phosphatase activity. V max of P uptake increased markedly under P deficiency, particularly for maize. Compared to the other plant species Cajanus, Chamaecrista , and Clitoria were characterized by a greater capability to absorb P at low external P concentrations. The nine cover crops and maize were also grown in pot experiments using two soils from northern Nigeria low in available P. The ultisol from Jos had a high P fixation capacity and was more acidic than the alfisol from Zaria. All plant species were precultured in the first season at 100 (Zaria) and 250 (Jos) mg P per pot. In the subsequent season, maize was uniformly seeded into all pots containing the remaining roots and the incorporated shoot dry mass (according to 15 mg P per pot) of the pre‐crop. No P and 250 (Zaria) or 500 (Jos) mg P per pot were freshly applied. Maize growth and P uptake were enhanced after legumes in Zaria soil. Cajanus showed the highest residual effect, and also Clitoria, Chamaecrista , and Lablab showed effects superior to the mean. In Jos soil, Clitoria, Cajanus , and Lablab enhanced maize growth above average. Also, a highly significant positive correlation between P uptake and biomass production was obtained. These results indicate that enhancement of maize growth after leguminous cover crops, at the low P supply of the soil used, mainly depends on P mobilization capacity of the cover crop.