NUTRIENT LEACHING LOSSES FROM A SANDY SOIL IN LYSIMETERS

Two lysimeter experiments were conducted on annual leaching losses of calcium (Ca), potassium (K), sodium (Na), chloride (Cl), sulphate-sulp hur (SO4-S) and magnesium (Mg) tone experiment only) from a sandy soil in central England during 1988-1995 to provide information on typical nutrient losses under arable agriculture below 1.2 m (Experiment 1) o r 1.5 m (Experiment 2). Total annual losses, in the absence of manure additions, were highly dependent on the amount of drainage; flow-weigh ted average concentrations were similar between years within experimen ts. Concentrations, averaged over the duration of the experiments were 7 1 and 78 mg L-1 Ca, 17 and 27 mg L-1 Na, 11 and 8 mg L-1 K, 74 and 77 mg L-1 Cl, and 57 and 38 mg L-1 SO4-S for the two experiments respe ctively; Mg concentration was 17 mg L-1. Applications of chicken litte r were made to some of the lysimeters in the last three years, and all nutrients showed increased leaching as a result. Application rates ak in to disposal (rather than for crop fertilization) produced the large st losses. Following a total application of 125 t ha(-1) over three ye ars, average concentrations in water draining below 1.5 m in the final year were 57 and 277 mg L-1 Ca, 22 and 75 mg L-1 Cl, 7 and 14 mg L-1 K, 22 and 57 mg L-1 Na, 27, and 125 mg L-1 SO4-S for the untreated and manured soils, respectively.