Non-symbiotic Nitrogen Fixation and Soil Fertility

Dart, P J and Wani, S P (1982) Non-symbiotic Nitrogen Fixation and Soil Fertility. In: Transactions of the 12th International Congress of Soil Science, 8‑16 Feb. 1982, New Delhi, India.

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Abstract

Soils in the semi-arid tropics (SAn are low in nitrogen and yet they continue to support most of the world's.milletsand sorghum production with virtually no addition df fertiliser. Legumes seem to play only a small role in the maintenance of soil fertility under the present management and cropping patterns. High levels of N can accumulate in soil under certain fallows planted to grasses such as Andropogon goyonus. Mineralisation mtes of 4 to 5% per,annum provide up to 70 kg N I ha per annum as nitrate, some of which may leach to soil depths of I to 2 m. Nitrogen removal in pearl millet or sorghum crops in such soils can beas much as 150 kg N/ha, depending on the cultivar and the season. Since inputs from other sources such as rainfall are small, the maintenance of equilibrium levels of soil N depends on biological N2 fixation. Bacteria associated with the root systems of sorghum, millets and some tropical grasses are involved, as well as blue-green algal crusts.

Item Type: Conference or Workshop Item (Paper)
Divisions: UNSPECIFIED
CRPS: UNSPECIFIED
Subjects: Others > Soil Science
Others > Fertilizer Appications
Depositing User: Mr Sanat Kumar Behera
Date Deposited: 11 Nov 2011 05:29
Last Modified: 11 Nov 2011 05:29
URI: http://oar.icrisat.org/id/eprint/3891
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