Rice growth and its indices for nutrient uptake from soils of Muda Irrigation Scheme

J. Mohd. Aris*

Abstract

Soil columns (each one cubic meter) of eight soil series from Muda Irrigation Scheme were used to study the growth and nutrient uptake of direct-seeded MR 84 rice variety. Rice growth was determined by soil fertility status, which was classified as low, intermediate and high fertility as based on yield. Low soil fertility regardless of soil series affected rice crop growth significantly (p <0.05). The variability in soil fertility status produced rice yield in the range of 3.8–16 t/ha with a mean of 8.8 t/ha. The cumulative biomass accumulation over the growing period (105 days) resembled the sigmoid growth curve. The period of rapid growth lasted for about 4–6 days between 60–68 DAS, 59–64 DAS and 57–61 DAS for the low, intermediate and high-yielding crop respectively. Their respective maximum growth rates were 24.4, 42.7 and 52.7 g/m2/day. During the period of rapid growth, the high-yielding crop displayed SPAD values of Y leaf in the range of 39–40. Nutrient composition between high and low crop yield indicated significant variation in nutrient imbalance (p <0.05). Hindrance to the achievement of high yield was due to the deficiency of Mg, P, Ca, S, Mn and Zn. The proportions of element taken up among nutrients of primer (N:P:K), secondary (Mg:Ca:S) and micro (Fe:Mn:Zn:Cu) throughout the entire growth period were 5.0:1.0:9.7; 1.2:1.0:1.5; and 48:46:27:1 respectively. The values of the important DRIS norms (N/S, N/K and Fe/Mn) at 60 DAS for high-yielding MR 84, were 10.6, 0.46 and 1.13 respectively. The concentration of N, P, K, Ca, Mg, S, Fe, Mn, Zn and Cu in leaf at harvest were 1.58%, 0.21%, 2.95%, 0.64%, 0.24%, 0.16%, 131.65 ppm, 95.20 ppm, 27.56 ppm and 1.04 ppm, respectively for the crop that achieved yield greater than 10 t/ha. The total nutrient uptake, the quantity of nutrient removed by the grain, the mineral requirement indices and the harvest indices for the respective nutrients were also identified.

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