Nitrification in Sudan Gezira soil

Jewitt, T. N.

doi:10.1017/s0021859600013599

Cited by 12 publications

(3 citation statements)

References 11 publications

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“…The extreme impermeability of the soil, furthermore, does not favour the possibility. Jewitt (1945) has obtained loss of ammonia from added fertilizers in this highly alkaline soil, but failed to detect liberation of ammonia from soil alone. The evolution of nitrogen peroxide from soils has been reported, but the degree to which this seems to occur does not offer a likely explanation of the very large losses that have been observed with Gezira soil.…”

Section: Nitrogen Studies On Soils O F the Sudan Gezira 223mentioning

confidence: 91%

Nitrogen Studies on the Irrigated Soils of the Sudan Gezira

Jones¹

1957

Journal of Soil Science

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Summary The seasonal variation in the organic‐ and nitrate‐nitrogen content of Gezira soil under irrigated rotational cropping has been studied over six successive years. Accent so far has been placed on the cotton phase of the rotations and statistical analysis of the results has shown that the organic‐nitrogen content of the soil is not increased by rotational cropping beyond an equilibrium value which is presumably a function of the environmental conditions. Increase of organic nitrogen in Gezira soil appears to be a function of seasonal conditions. Loss of organic nitrogen in marked excess of what could conceivably be explained by crop uptake is a definite feature. The loss occurs gradually throughout the whole season, giving a minimum organic‐nitrogen content in the soil during the hot dry period of February to May. Accumulation of nitrate‐nitrogen, on the other hand, is dependent on the nature of the rotation and the period of the year. Nitrate accumulates at the beginning of the rainy season when it is rapidly leached to lower soil depths; it also accumulates on the bare fallows during the hot dry season. This latter finding is in accord with the statements of other workers.

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Section: Nitrogen Studies On Soils O F the Sudan Gezira 223mentioning

confidence: 91%

Nitrogen Studies on the Irrigated Soils of the Sudan Gezira

Jones¹

1957

Journal of Soil Science

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“…Crowther (1943) assumed that these benefits arise from the im roved physical condition of the soil through desiccation which should P ead to improved nitrifying conditions and hence to a greater degree of nitrification. Jewitt (1945) has shown that Gezira soil is not generally deficient in nitrifying bacteria and that no striking differences exist in this respect between this soil and soils of other arid regions. The present work sup orts Crowther's assumption and it appears that these experiments.…”

Section: 08mentioning

confidence: 78%

Nitrogen Studies on the Irrigated Soils of the Sudan Gezira Ii. Extended Fallowing in Cotton Rotations

Jones¹

1958

Journal of Soil Science

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Seasonal fluctuations in organic nitrogen and nitrate nitrogen in the soil of the Sudan Gezira are described under conditions of extended fallowing in cotton rotations. Statistically, results show that soil organic nitrogen is independent of rotational phase. Cotton yields are not limited by the content of organic nitrogen in the soil, but by soil physical conditions which improve by extended fallowing. Evidence is presented to show that soil organic nitrogen and nitrate nitrogen in this soil do not function in close interdependence. This conclusion was drawn in other work previously published.IN a previous paper (Jones, 1957) the author described the changes in organic-nitrogen content that occurred under three-course rotational cropping in Sudan Gezira soil. The field experiment used for the investigation was one of the long-term rotation experiments at the Gezira Research Farm, Wad Medani, Sudan; but the practical value of the experiment in terms of the general agriculture of the area was limited. Although the frequent cropping involved in a three-course rotation might economically offer a better gross agricultural output than a rotation containing a longer fallow eriod, it was known that under the intense of better weed control through cessation of watering. What was not known, however, was the optimum length of fallow.In order to investigate this point a 'combined-rotations' experiment (Crowther and Cochran, 1942) was laid down, and the present paper describes a study of the changes in soil organic nitrogen and nitrate nitrogen that occur under extended fallowing on this experiment in the Gezira. The experiment was planned to provide a com arison between ing cotton together with the variations from inclusion of intervening dura (Sorghum oulgare) and lubia (Dolichos Zablab). Ten rotations were involved with a total of thirty phases. The different treatments were completely randomized in each of five blocks making a total of 150 sub-plots. Each sub-plot was 4 feddan" in area.Data for the dura and lubia variations are not included in the present paper, which is restricted to an examination of soil samples taken from all hases of the following rotations: A, continuous cotton; M, cotton an one ear fallow; G, cotton and two years fallow; K, cotton and three years fa low. The five rotation replicates per phase were sampled for * I feddan = 1.038 acres. heat of the Central Sudan P allowing was highly beneficial and permitted one-, two-, three-, and four-course rotations in terms o F fallows follow-

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“…Analytically they could account for practically all of the added ammonia which indicated that losses by volatilization from the soil or by spontaneous decomposition of ammonium nitrite were negligible. This was not corroborated, however, by Jewitt (10) working with Sudan Gezira soil. Nitrification of various materials in his experiments was normal but appreciable ammonia was lost from alkaline soil when it was added as ammonium sulfate.…”

mentioning

confidence: 79%

Microbiology of Soil

Smith¹

1948

Annu. Rev. Microbiol.

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Nitrification in Sudan Gezira soil

Cited by 12 publications

References 11 publications

Nitrogen Studies on the Irrigated Soils of the Sudan Gezira

Nitrogen Studies on the Irrigated Soils of the Sudan Gezira

Nitrogen Studies on the Irrigated Soils of the Sudan Gezira Ii. Extended Fallowing in Cotton Rotations

Microbiology of Soil

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