Two experiments were carried out in 2008 and 2009, in four locations in Cross State, to determine seasonal variations in the commonly grown rice varieties. Their response to different photoperiod treatments were investigated with rice plants in polyethylene bags subjected to varying lengths under artificial light. High photoperiod - sensitive varieties, showed significant difference in their maturation periods when planted at different times of the year. The longer growth duration occurred when plantings were made in January - February. The shortest growth duration occurred when plantings were made in the October - November period. In some of the photoperiod - sensitive varieties, there were big differences in the growth duration when planted in the same month, of different years. These varieties would be unsuitable for planting during the off season (August to September). The results are discussed in light of photoperiod sensitivity of some rice varieties planted at different times of the year.KEYWORDS: Seasonal variation, growth duration of rice.

Oban Hills is located at Akamkpa in the Southern Senatorial District of Cross River, State, Nigeria. Phosphorus (P)-rich soil from the Hills is expected to have an effect on retention and distribution in the highly acidic soils surrounding the area inundated for several years. Phosphorus forms in the soils of the Hills varied with the year of deposition with the highest fraction being Ca-P. The low soil pH in the Oban Hills soils suggests that Ca-P may exist in a partially dissolved form and will be the primary source of P for vegetations around the area. The cation exchange capacity and pH of surface material from the Hills suggest a dominance of primary minerals. Based on the amount of P available it seems that the Hills soils play a role in the overall P availability to the surrounding vegetation. A significant (P<O.05) decrease in HCI soluble P with depth was observed in the OB2 soil site, where the greatest amount of HCI-soluble P was found in the 0-15cm soil depth. The bicarbonate P varied with sites (OBI, OB2 and 0B3), and depth, but the OB3 had the highest value. KEYWORDS : Phosphorus, Soils, Oban Hills, P-fixation, P-distribution

Investigation of the chemical properties of the coastal plain soils treated with NPK 20:10:10 fertilizer (NPK) at the rate of 0,60, 90 and 120kg ha-1) and observed at intervals of 3,6,9 and 12 months was carried out from March 2009 to 2010 at Akpabuyo, Cross River State, Nigeria. The experiment comprises of four fertilizer rates and four management intervals fitted into a Latin square design. The soils pH value increased consistently from 3 to 12months. Mean values of organic matter decreased with increase in profile depth from 2.12-1.34g kg-1). The distribution of N from the top soil down the profile increased consistently from 3 to 12 months. The mean value of N from the top soil was 0.82%. Exceeding 0.2%, the critical value and was more than the mean values obtained in the sub-surface soil. The mean value of P (33 mgkg-1)) during the 9 months interval was significantly (P<0.05) higher than all other samplingperiods. There was vertical and horizontal loading of P which lead to higher available P at the surface in soil depths of 0-15 and 15-30cm than 30-40cm and 40- 50cm. Levels of Ca increased slightly with sampling interval but decreased down the profile. The soils were also characterized as follows: strongly acid (pH 5.1 – 5.3), exchangeable Mg. (> 0.5cmol kg-1)), low contents of K and Na as well as high exchangeable Al. levels (> 4.0 cmol kg-1)) and cation exchange capacity (22 – 36 cmol kg-1)) The application of 90 kg/ha-1) NPK fertilizer during the 9 months interval gave highest values of N.P, Ca and Mg under the condition of the experiment, indicating that these elements will not be deficient in these soils. Equally, the CEC, organic matter and base saturation had their advantage in the 9 months interval where 90 kg'' was applied. This is cost effective and could be used to improve crop production in Akpabuyo, Nigeria.KEY WORD: Chemical Properties, NPK Fertilization, Management Intervals, Coastal Plain Sands.

A study was carried out in May 2008 using Seven Conventional methods for estimating available soil phosphorus from swamp mud, in acid sulphate soils of Mbiabet, Akwa Ibom State, Nigeria. The Seven extractants were tested to determine which would be suitable for routine use in the water-logged soils. The extractans were Bray and Kurtz’s (0.03NNH 4 F in 0.025N Hcl), Morgan’s (10% NaOAC/3%HOAC), Sounder’s (0.1NNOOH), Olsens (0.5N NaHCO 3 at pH 8.5). Treatment consisted of potassium dihydroxide added in the doses of 0, 50, 100, 150, 200, 250 and 300mg/kg, fitted into Latin square of 36 x 5m. Limestone (Ca CO 3 ) was applied at the rate of 50 kg/ha to reduce the activity of aluminum. The results of the selective tests showed that the Oslen’s procedure gave the most reliable estimate of available P. Fractionation of the forms of inorganic phosphorus in the phosphate treated mud showed that the extracting solutions removed chiefly aluminium phosphate. In the absence of facilities for field, the relationship between crop response, concentration of soil phosphorus and available phosphorus as determined by Olsen’s procedure gave the most reliable estimate of available P. was estimated for polyethylene bag culture experiment with rice and maize. Response to additions (Rice and Maize) had available P 11 mg/kg with Oslen’s method.

The estimation of water requirements of early and late season tomato was conducted based on 10 years meteorological data at Calabar typical of the humid tropical zone, using the Penman’s equation. Results showed thatthe seasonal crop evapotranspiration (ETo) value for early season tomato (March – July) was 60.8mm/day, while that of late season (September – December) was 73.6mm/day. The result showed that the water requirement for the late season was 2.0% higher than the early season tomato. However, water deficit tended to be greater in flowering than at yield formation. The calculated monthly crop coefficient (Kc/month) values for early season and late season tomato (the initial, crop development, and late season stages) were the same. The Kc values increased from low value at a time of crop emergence to a maximum value during the period when the crop reached full development, and declined thereafter when the crop matured. These results are discussed in light of estimation of water requirement of early and late season of tomato in Calabar.

In 2006 aluminum and iron contents were determined in phosphate treated swamp rice farm of Mbiabet, Akwa Ibom State. The objectives were to determine the aluminum and iron contents, the effect of drying, phosphate and lime application in an acid sulphate soil grown to rice in Nigeria. The soil samples used were mud-clay from the bottom of the water-gate and cat-clay from the stream banks that bring water to the swamp. The third was from the unfertilized pond-mud taken from the Latin square of 36 x 5m, which had received surface limestone dressing of 50kg/ha but with no phosphate. The phosphate fertilizer was applied at 122kg/ha-1 P205. Various extractants used to extract Fe and Al showed highest concentration of Fe and Al in the sulphuric acid and dithionite and lowest in the sodium hydroxide citrate extractants. The total amount of Fe and Al removed by the fractionating solution represented 75 and 15 percent respectively. The average values of pH and KCl-extractable aluminum and iron at various depths showed that as the pH decreased the amount of extractable Fe and Al increased in both fresh and dried muds down the profile. Iron phosphate was more abundant than aluminum or calcium phosphate throughout the profile and there was no aluminum phosphate present below a depth of 8 cm. These results were consistent throughout the study period.

A study was conducted in April 2006 to determine the phosphate relationship in acid sulphate soils of Mbiabet Swamp Rice farm in Akwa Ibom State, Nigeria. Soil samples were collected in the order of 0 – 1, 1 – 2, 2 – 5, 5 – 8, 8 - 10 and 10 - 15cm soil depths. Treatments consisted of potassium dihydrogen phosphate added to the swamp mud, cat-clay, and mud-clay in equal doses of 122 kg/ha P205, fitted into Latin square of 36 x 5 m swamp, except for the control plots. Limestone (CaC03) was applied to both fertilized and unfertilized plots at the rate of 50 kg/ha to reduce the activity of alumimium. The distribution of phosphate in the top 10 cm of unfertilized plots at the fresh and dried mud showed that the bulk of the total phosphorus was in the organic and occluded forms. There was no saloid-bound phosphorus present in either the fresh or dried mud. The fixation of phosphorus was rapid, reaching the equilibrium within 50 - 75 hours. Fresh mud (except cat-clay) absorbed more phosphate than did dried mud and nearly 60 percent of the absorption took place within 6 hours. The soluble phosphate applied as solution to columns of air-dried swamp mud showed a decrease within 6 months, but calcium and organic phosphate increased. Saloid-bound phosphate with the water-logged cat-clay decreased considerably. The soils have great opportunities in rice production when given proper soil management.

A solution culture experiment was carried out in April, 2003 at Calabar using two cultivars of pineapple suckers (Ananas Comosus) smooth Cayenne, and Queen to assess the Al toxicity to pineapple solution culture, consider the Al up-take, and attendant Al symptoms, together with shoot and roots growth. The treatment consisted of three levels of Al concentrations 0, 0, 0.35 and 0.070mmol dm-3, combined with four levels of ionic strength produced by diluting a complete nutrient solution to relative concentration of 1.0, 0.5, 0.25 and 0.12. The phosphorus (P) ion concentration of each solution was adjusted to 0.1mmol dm-1. The pH of the solution was maintained at 4.5  0.3. The results showed that shoot and root growth decreased significantly under the Al treatments. The observed lateral roots of AI stressed plant of the two varieties was significant (P