Sugar Cane Growth in Response to Mulch and Fertilizer on Saline-Alkali Subsoils
1977
Eavis, B. W. | St. J. Cumberbatch, E. Rs
In many parts of the world where salinity or alkalinity limit crop yields, leaching is impracticable. In Barbados saline-alkali subsoils remained unproductive 6 years after they were exposed during earth-moving operations. The objective of this study was to devise agronomic techniques to restore these lands to sugar cane (Saccharum officinarum L.) production. The effects of mulching and N-K fertilization were studied. Factorial field experiments in which bare plots and plots mulched with cut grass were treated with fertilizer at three rates (70:82, 208:247, 416: 495 kg NK/ha) were carried out at two locations (sandy clay and clay soil respectively). Sugar cane tillers and soil moisture contents were measured weekly, and root development fortnightly. After 9 months of growth bare plots failed to produce any marketable yield in contrast to mulched plots which gave up to 53 metric tons/ha (sandy clay) and 118 tons/ha (clay). There were no responses to fertilizer rate on bare land, but on mulched land 1.2 times (sandy clay) and 2.2 times (clay) more yield resulted from the high compared with the low fertilizer rate. Regression analysis indicated the importance of root development and nutrient uptake to tiller elongation rates in rainy periods. In drier intervening periods of slower shoot growth, soil moisture status was most important, mulched land having a volumetric moisture content 4% higher than bare land. Mulching reduced run-off and increased rainfall preservation. The experiments show that growth and response to fertilizer on saline-alkali soils depends on the soil physical environment. Mulching combined with adequate fertilizer application is a satisfactory reclamation procedure for saline-alkali soils in the semi-arid tropics.
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