Influence of Polyethylene Mulch and Magnesium Salts on Tomatoes Growing on Loamy Sand
1978
Jones, U. S. | Jones, T. L.
Plant-soil responses to mulching with 0.0375 mm thick white-overblack polyethylene plastic and to two sources of Mg were studied by analyzing soil samples, plant tissues, and yields associated with three crops of irrigated tomatoes (Lycopersicon esculentum Mill.). These crops were grown on 5.51 m² plots of Blanton loamy sand in 1976-77. Ten and 20 kg/ha of Mg as MgSO₄ · 7H₂O and 20 kg/ha of Mg as CaMg(CO₃)₂ were added each season to mulched and unmulched soil. Yield of marketable tomatoes, S and Mg content of the fourth leaf from tip, and exchangeable Ca, Mg, and buffer pH of soil to a depth of 60-cm were measured. Yield was significantly increased in the first crop where Mg was added, either as MgSO₄ · 7H₂O or dolomite on mulched soil. Tomato-leaf Mg (0.78%) of the second crop was greatest where 20 kg/ha of Mg as MgSO₄ · 7H₂O was added to the mulched plots although the yield increase was not significant. Leaf Mg content was significantly increased by 20 kg/ha of Mg as MgSO₄ · 7H₂O in second and third crops whether or not plastic mulch was used. Dolomite increased Mg in the leaf of the third crop. Mulched soil (0 to 15 cm deep) had a higher buffer pH and exchangeable Mg and Ca than did the uncovered soil. No significant difference in cations was noted at greater soil depths.
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