Mineralogy profile of some rice irrigation water in Southern Nigeria
William Ubi, Godwin Michael Ubi, Ackley Ufot Akpan-Idiok, Thomas Okweche
Experiments were conducted in 2013, 2014 and 2015 on the quality of some rice irrigation water at Adim, Idomi, Assiga and Ofodua in Cross River State, Southern Nigeria to determine their rate of nutrient supply. The results showed that Adim location was more acidic with pH range of 4.5 to 5.6 with a mean of 5.1 on the average, compared with a pH of 6.1 each for either idomi, Assiga or Ofodua. The Ca, Mg and K values were moderate and will not be a problem to rice cultivation. A minimum of about 1/8 of the Ca and 1/3 of Mg were removed from the grain. The amount of K used by the plant in the water culture experiment was much higher than those of Ca and Mg. The N in irrigation water was relatively high in all the study areas and the amount removed in grain was considerable. The four irrigation waters studied were found to have good supply of these elements and deficiency will not be a problem for rice production. The supply of P by irrigation water was moderate to low in the four study areas, but the highest value was found at Ofodua. Culture solutions used very much larger quantities of phosphorus and more than 10.2% of total P was found in the grain. The conductivity was much less than 1000 x 106 Mhos, which is the toxic level for rice, and will not be detrimental to good yields of rice. The mean value of N:P:K:, Ca, Mg, Mn and Fe were significantly (p<0.05) higher in the straw than in the grain in all the samples studied. Comparing the mean values of Mn with those of Fe, Mn values were more than double those of Fe throughout the study period.