Long-Term Effects of Fertilizers and Manure on Soil and Leaves of Cotton in Nigeria

Abstract

On a site in the Sudan Savanna, chemical properties of soils (except for phosphate) and the composition of cotton leaves were determined after fifteen annual treatments including dung, ammonium sulphate, single superphosphate and potassium chloride, in all combinations of three levels. In the soils dung increased C, N, cation exchange capacity, exchangeable Ca and Mg and pH, and decreased soluble Al and Mn; ammonium sulphate decreased pH, increased soluble Al and Mn, and decreased exchangeable Ca and Mg; potassium chloride had no obvious effects. In the plants dung increased P and reduced Mn; ammonium sulphate reduced Ca and Mg, and increased Mn; superphosphate increased P, Ca and Mg, and reduced K; potassium chloride increased K slightly. The most important results were the ability of ammonium sulphate to acidify the soil, as shown by soil properties and reflected in tissue composition, and the ability of dung to ameliorate these effects. Reduction of crop yield in the presence of adequate nutrient supply seems to have been due to excessive soil acidity.In 1949-50 a number of manurial trials, designed to test the effects of four materials separately and in all combinations, were started in Northern Nigeria. The materials and their rates of application were: D-Dung (cattle pen manure) o, 1 and 2 tons/acre N-Ammonium sulphate (21 %N) o, 50 and 100 lb/acre P-Single superphosphate (8-7%P) o, 50 and 100 lb/acre K-Potassium chloride (42%K) 0, 25 and 50 lb/acre.A 3 4 factorial design was used and the total of 81 plots was arranged in 9 blocks. Plot size was 1/20 acre, with adequate discards, and each plot received the same manurial treatment each year. Many of these trials were stopped in 1957, and Obi (1959) summarized the effects on crop yields up to that time, but three of them were continued. The trial at Samaru has been mono-cropped with sprayed cotton since 1961, and this paper reports the effects of the fertilizer and manure treatments on some chemical properties of the soil and on the composition of leaf samples from the cotton crop with respect to certain chemical elements. MATERIALS AND METHODSThe site of the experiment is within the Sudan Savanna zone and has a light brown loamy fine sand topsoil, with a sharp boundary at about 8-9 in. to a loam/sandy clay loam subsoil. Acid metamorphic rocks are thought to underlie the site, but the soil also incorporates a considerable amount of drift material.

Initial responses of maize and beans to decreased concentrations of monomeric inorganic aluminium with application of manure or tree prunings to an Oxisol in Burundi

“…This is contrary to extrapolations from pot experiments, which suggest that unrealistically large levels of applications are required (Bessho and 281 Bell, 1992). These results confirm earlier field observations which showed that organic residues improved soil acidity under realistic field conditions (Bache and Heathcote, 1969;Kretzschmar et al, 1992;Le Mare, 1971). The positive effects in the soil is probably due to the freedom of the newly formed decomposition products to react with reactive A1 sites on mineral surfaces.…”

“…For example, Bessho and Bell (1992) estimate that 14 t ha -1 of a legume leaf or 42 t ha-l of barley straw were required to bring the activity of A1 in a red podsol to < 10 #M which are required for soya beans. Increased soil pH and decreased AI saturation have however been observed with lower rates of organic matter applications under field conditions in Nigeria, Tanzania and Niger (Bache and Heathcote, 1969;Kretzschymar et al, 1991;Le Mare, 1972). The causes of such pH increases are not fully understood.…”

The cation exchange properties and microbial carbon, nitrogen and phosphorus in savanna Alfisol under continuous cultivation

“…This study would recommend that a balanced fertilisation programme for weathered savanna soils with low CEC and bu †ering capacity is that which combines inorganic fertiliser with farmyard manure. This conclusion is in concord with the observation of Bache and Heathcote (1969), from the same long-term experimental Ðeld at Samaru, that soil chemical fertility constraint imposed by inorganic fertiliser : use for 19 years can be removed with farmyard manure. This 19-year-old prescription is not only applicable to the soil chemical fertility but also to the biological fertility criteria, even after 45 years of cultivation.…”

“…While studies continue to justify the beneÐts of inorganic fertiliser in savanna soils, complementary studies on the long-term e †ects of inorganic fertiliser on these poorly bu †ered soils are lacking. Bache and Heathcote (1969) showed that ammonium * Present address : School of Science, College of Education, Akwanga, Plateau State, Nigeria. " To whom correspondence should be addressed.…”

Comparative studies on the mineralization of furfural urea and urea fertilizers in an alfisol in Samaru Zaria, Kaduna State, Nigeria

“…The soils are exposed to true high temperature and rainfall concentrated over a period of five months of the year. The prolonged use of chemical fertilizers especially N fertilizers gives rise to residual soil acidity and cation depletion (Jones, 1989, Bache andHeathcote, 1988). Under intensive agriculture now commonly practiced, soil fertility declines rapidly after a few years of continuous cultivation.…”