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1.
Victor I. Okereke E. Robert Baumann T. Al Austin Donna Schulze Lutz 《Water, air, and soil pollution》1988,37(3-4):325-341
The impact of a flood control, low flow argumentation reservoir in the Midwestern part of the United States on BOD, COD, and ammonia was evaluated in this paper. Fifteen years of weekly water quality data (9 yr before impoundment and 6 yr after impoundment) from four sampling stations upstream and downstream of the reservoir were available for analysis. The annual loading rates of these parameters (kg ha?1 vr?1) were found to correlate well with annual runoff (cm yr?1). Besides, the reservoir was found to have had a significant and beneficial impact on the downstream loading rates of BOD and COD, which were reduced by 55 and 75%, respectively. As for ammonia, the results of this study indicate that its annual loadings at downstream locations were not significantly affected by the reservoir. Average non-point source contributions of BOD and ammonia loadings into the system were found to be about 80 and 55%, respectively. 相似文献
2.
Summary Sources of N used by cropped and intercropped cowpeas and rice were determined by the 15N isotope-dilution technique. The biological efficiency of intercropping cowpeas and rice was assessed by calculating the land equivalent ratio of dry matter yield, total N, and uptake of N. A reduced N uptake by both cowpeas and rice during mixed cropping was attributed to mutual competition, with both crops competing effectively for the scarce environmental resources. The lack of a significant difference in the uptake of fertilizer and soil N by mixed-crop rice and cowpeas is an indication that the soil N was sufficient and that the mixed cropping did not create any imbalance in soil and fertilizer N uptake. The land equivalent ratio ranged between 120% and 180% for shoot dry matter and total N, showing that biological efficiency was increased by intercropping cowpeas with rice. The proportion of N derived from the atmosphere by mono- and intercropped cowpeas was not significantly different, showing that the potential of cowpeas to fix N2 was independent of the cropping system, since the rice did not stimulate the cowpeas to fix more N2. 相似文献
3.
O. Okereke 《Agricultural Systems》1982,9(4):239-253
This study was carried out in the Igbo Eze Local Government Area of the Anambra State of Nigeria, approximately 100 km from Enugu, the state capital. Four of the sixteen communities that make up the Local Government Area were selected by random sampling. From each of the four communities, a village was selected at random and from each of those four villages, a random sample of fifty farmers was drawn.The system of oil palm wine production in the area of study can be described as traditional in the sence that it is based on methods which have been in operation for generations. The palms available for tapping are the wild palms, most of which are old and of dwindling productivity.Empirical evidence showed that the tappers had not been exposed to any changes in organisational structure or institutions concerned with the oil palm smallholder rehabilitation scheme which could be utilised to improve the productivity of their palms. Nonetheless, the traditional system provides the farmer-tappers with some means of livelihood.Being market-oriented, the farmers are keen on adopting innovations which promise increased palm wine yields and increased farm incomes. Government assistance, through the provision of credit on liberal terms to enable the farmers to improve and modernise their holdings, as well as the introduction of new oil palm varieties with increased yield potential, should be considered. 相似文献
4.
Chrysanthus Chukwuma Sr. 《Water, air, and soil pollution》1996,86(1-4):13-34
Agricultural soil samples were collected about 1 km apart over 21 km from 32 tilled/cultivated plots of yam, rice, and cassava in urban, rural, and the derelict Enyibga lead-zinc mine (EM) in the Abakaliki area, Nigeria during the rainy season in September, 1992. In the derelict mine, mean elemental contents increased in the order Cd < Ni < Cu < Mn < Pb < Zn; while in the urban, rural, and all soils combined, the order increased as follows: Cd < Cu < Ni < Pb < Zn < Mn. The overall mean distribution of all soils shows Mn and Zn to approach and exceed toxic levels, respectively. In all soils, the total mean concentrations of Cu and Ni are well below toxic levels. The Abakaliki area is less likely to be subjected to Cd-contaminated soils. Pb was excessively high at EM and, moderately high at Mgbowo Street in the urban area, but very less so in the rural areas. The rural agricultural areas of Agbaja, Nkwaegu, and Amaegu, including the isolated Ezza Road as well as the peripheral Expressway had relatively lower levels of heavy metals, pH and organic matter content than the urban conglomeration of Mile 50, Mgbowo Street, and Azuiyiokwu including the derelict mining village of Enyigba and EM; except that Ezza Road had pH and organic matter as high as the densely populated urban cultivated areas. The relationship between bulk density and organic matter was highly dependent on pH. 相似文献
5.
Ariahu CC Ukpabi U Mbajunwa KO 《Plant foods for human nutrition (Dordrecht, Netherlands)》1999,54(3):193-206
Germination and fermentation were investigated as methods of improving the nutritional and organoleptic properties ofsoybean and African breadfruit seed based food formulations.Four products consisting of germinated-fermented soy-breadfruitseeds (GFSB), nongerminated-fermented soy-bread-fruit seeds(NGFSB), germinated-nonfermented soy-breadfruit seeds (GNFSB)and nongerminated-nonfermented soy-breadfruit seeds (NGNFSB)were prepared. Phytic acid contents, in vitro protein digestibilities, protein efficiency ratios (PER), net proteinratios (NPR), flavor, appearance and overall acceptabilitywere evaluated. Germination followed by natural lactic fermentation significantly (p < 0.05) reduced the phytic acid by a factor of 11.6 in NGNFSB compared to reductionfactors of 2.1 and 1.5 in GNFSB and NGFSB, respectively.The in vitro protein digestibility (%), PER and NPR valuesof 73.4, 2.46 and 3.62 for GFSB; 71.1, 2.35 and 3.46 for NGFSB;68.7, 2.16 and 3.41 for GNFSB were significantly (p < 0.05)higher than the 64.7, 1.82 and 2.11 for NGNFSB. The meansensory scores were 5.26–5.67 for GNFSB, 4.66–4.94 forNGNFSB, 4.33–4.80 for GFSB and 4.27–4.34 for NGFSB on a7-point rating scale. 相似文献
6.
Alfred G. O. Dixon Malachy O. Akoroda Richardson U. Okechukwu Francis Ogbe Paul Ilona Lateef O. Sanni Chukwuma Ezedinma Jones Lemchi Gorrettie Ssemakula Marie O. Yomeni Emelike Okoro Gbassey Tarawali 《Euphytica》2008,160(1):1-13
The aim of the Integrated Cassava Project (ICP) of the International Institute of Tropical Agriculture was to pre-emptively
manage the cassava mosaic disease (CMD) to avert an imminent and increasing possible threat of the Ugandan strain of the CMD
virus of the pathogen from doing damage to the Nigerian cassava economy. The strategy was to engage in activities that would
lead to cultivar-substitution by replacing the susceptible varieties on farmers’ fields with superior genotypes that are not
only CMD resistant or tolerant but also high yielding with good dry matter content. A fast track participatory selection approach
was used in 2 years to release nine new lines in Nigeria. It was intensive and several lessons were learnt. The varieties
released after 2 years were TMS 98/0510, TMS 98/0581, TMS 97/2205, TMS 98/0505, TME 419, TMS 92/0326, TMS 96/1632, TMS 98/0002,
and TMS 92/0057. 相似文献
7.
Field experiments were conducted to investigate the performance of three soybean cultivars with five foreign bradyrhizobia
strains in different regions. The experiments at the two sites were designed with soybean (Glycine max L.) cultivars as the main factor and bradyrhizobia strains (USDA 136, TAL 122, USDA 6, TAL 377 and TAL 102) as the sub-factor.
The experiments were arranged in randomised complete block design with four replications. Results show that nodule number,
nodule dry weight and shoot dry weight, total N and seed yield were significantly increased when soybean cultivars were inoculated
with foreign bradyrhizobia in two locations in the south east of Nigeria. At 63 days after planting the percentage increase
in nodule number and dry weight after inoculation of soybean cultivars with bradyrhizobia strains ranged from 71 to 486% and
from 0 to 200%, respectively. The percentage increase in shoot dry matter, %N and total N after bradyrhizobia inoculation
ranged between 2–130%, 18–62% and 35–191%, respectively at Awka, and at the Igbariam site the percentage increase in shoot
dry weight, %N and total N ranged between 3–76%, 0–43% and 19–125%, respectively. Seed yields after bradyrhizobia inoculation
of soybean cultivar TGX 1485–1D at Igbariam ranged between 1.20 and 2.18 t ha–1 against the uninoculated plants, which had seed yields of 1.05 t ha–1. The poorest yield response after inoculation with bradyrhizobia strains was observed in soybean cultivar M-351, with a seed
yield ranging from 0.60 to 0.98 t ha–1. The fact that foreign bradyrhizobia strains were more effective than the indigenous strains for all the parameters studied
suggests that there is a need to use bradyrhizobia inoculants for increased soybean production in Nigeria. The variations
in the strain performance with the different soybean cultivars at the two sites, emphasises the need for careful Bradyrhizobium spp. strain selection. The fact that inoculation response was cultivar- and site-specific suggests that strategies for improving
inoculation response in soybean cultivars should also consider the soil environment where the soybean is to be produced.
Received: 25 May 1999 相似文献
8.
The need for an indigenous croplocally grown by subsistence farmers that willhelp bring direct economic benefits to thosewho need it most is very important. Cassava hasa great potential for this purpose if certainproblems are solved, because cassava has playedvital roles in the diet of many Africancountries especially the grassroot people, yetthe utilization of the crop in diversifiedforms has been very limited. There are few foodproducts from cassava that are processedindustrially with added value that will be ofhigher nutritional value and have longer shelflives. There are a number of traditionallyprocessed staple foods from cassava in Nigeriaand other African countries that needimprovement. Most of these foods can beimproved on if the market for them is assuredby the end users, a market that is currentlylacking. It will be necessary to create morepublic awareness within Nigeria and otherAfrican societies to increase the acceptabilityof such novel products and this requires amultidisciplinary approach to interpret whatscientists and technologists are doing to theold crop in the present age. 相似文献
9.
Victor I. Okereke E. Robert Baumann T. Al Austin Donna Schulze Lutz 《Water, air, and soil pollution》1988,37(3-4):309-324
Both qualitative and quantitative approaches were used to evaluate the impact of a flood control, low flow augmentation reservoir on seven water quality parameters: Suspended solids and total phosphate (particulate parameters); BOD, COD, and ammonia (O2-demanding parameters); and orthophosphate and nitrite plus nitrate N (soluble nutrients). Fourteen years of weekly sampling data above, in, and downstream of the reservoir both before and after the reservoir became operational were analyzed. This paper considers the effects of the reservoir on the particulate parameters. There was a dramatic decrease in both suspended solids and total phosphate concentrations in the reservoir discharges, particularly during periods of high river flows and high reservoir inflow parameter concentrations. At all sampling stations, the annual parameter loading rates (kg ha?1 yr?1) correlated linearly with annual runoff (cm yr?1). The suspended solids removal efficiency of the reservoir was dependent on annual runoff and averaged about 90%. Non-point source contributions of suspended solids were well over 99% when annual runoff exceeded 6.57 cm y?1 and over 95% even when annual runoff was as low as 1.63 cm yr?1 相似文献
10.
Ariahu CC Ukpabi U Mbajunwa KO 《Plant foods for human nutrition (Dordrecht, Netherlands)》1999,54(3):207-216
The effects of germination (G) and naturally fermented (F)on the bacterial flora, viscosities and moisture sorptionisotherms of soybean (S) and African breadfruit (B) seed based food products were investigated. Bacillus,Enterobacter, Enterobacteriaceae, Proteus, Serratia andStaphylococcus species dominated in the nonfermentedproducts. Lactobacillus, Leuconostoc, Pediococcusand yeast species dominated in the fermented products whosegruels also inhibited growth of coagulase positive Staphylococcus aureus in challenge tests. Germination andfermentation resulted in significant (p < 0.05) decreasesin cooked paste viscosities which is advantageous inincreasing nutrient density. The monolayer moisture contents (g H2O/g solid) and surface areas for monolayer adsorption (m2/g solid) derived from BETmodel were 0.0422 and 148.1 (GFSB); 0.0428 and 150.4 (NGFSB); 0.0436 and 153.3 (NGNFSB); 0.0531 and 186.6 (GNFSB), respectively. 相似文献