Lime and P Applications and Their Residual Effects on Corn Yields
1978
Lim, K. L. | Shen, T. C.
Lime need for corn (Zea mays L.) production has been widely recognized in Malaysian soils. Little work has been done, however, to study the chemical behaviour of these soils after applications of lime. This field study was conducted to monitor some of the chemical changes in a Serdang colluvium (Tropofluvent) soil when lime and phosphate fertilizer were applied to corn. The residual effects of these treatments on the nutrition and yield of corn were also studied. Six consecutive corn crops were grown over a 2-year period. Ground limestone (CaCO₃) at 0, 3,000, and 6,000 kg/ha and P (triple superphosphate) at 50, 100, and 150 kg/ha were applied. Ground limestone was applied for the first crop and half of the P levels were applied for the first crop while the other for the second crop. Their residual effects were observed for six crops. Results indicated that 3,000 kg/ ha of limestone was sufficient to maintain yields for the first three crops while 6,000 kg/ha provided sufficient lime for all six crops. Grain yield responded significantly to I00 kg/ha P and continued to provide enough P through the sixth crop. Liming increased soil pH from 4.3 to 5.5 and decreased exchangeable AI and % AI saturation from 1.9 to 0.3 meq and 67 to 7%, respectively. A strong negative relationship existed between grain yield and exchangeable AI which accounted for 74% of the yield variations. Leaf Mg concentration was also increased from 0.14% to 0.40% with lime application. Plant analysis showed that poor plant growth on unlimited plots was not due to poor P uptake. Grain yield, available P, and leaf P concentration relationships showed critical available P at 25 ppm and P concentration at 0.27%.
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