Losses of nitrogen and other plant nutrients to drainage from soil under grass

Abstract

SummaryDrainage lysimeters were used to estimate actual transpiration of a perennial ryegrass sward; this is compared with the calculated values for potential transpiration. Losses to drainage of nitrate nitrogen (NO3–-N) under differing levels of application of nitrogen fertilizer were examined. When 250 kg N/ha were applied annually losses of NO3-N were negligible; when 500 kg N/ha were applied up to 142·9 kg N/ha were lost to drainage. Concentration of NO3-N in the leachate with an application of 250 kg N/ha was low (1–5 ppm); with 500 kg N/ha the concentration ranged from 10 to 109 ppm. Losses of NO3–-N were particularly severe during winter following a dry autumn. When drainage occurred during the growing season losses were minimal.Concentrations and quantities of K, Ca, Mg, Na, P, Cl and S (as sulphate) leached wore also examined.

The effects of injecting nitrapyrin (‘N‐serve’), carbon disulphide or trithiocarbonates, with aqueous ammonia, on yield and %N of grass

“…Winter leaching losses of N applied to grassland in the previous spring or early summer are probably only a few kg ha-1.9J0 In three successive years, little if any of late summer dressings of nitrate-N (125 kg of a total of 500 kg ha-l year1) was leached during the subsequent winter, from free draining soils in grass-covered lysimeters at Newcastle upon Tyne and Aberystwyth.ll However, in similar lysimeter experiments at Hurley (sandy loam over chalk), most or all of the final dressing was leached. 12 These results support the view that on many soils only a small proportion of the NH3 injected in autumn is likely to be leached in most winters from grassland in south-eastern England. The amounts of N injected in our experiments were moderately large, and typical of those applied by contractors so that, whether or not a small proportion of this applied N is saved by an inhibitor, the effect on yield can be expected to be slight.…”

Nitrate leaching from liquid cattle manure compared to synthetic fertilizer applied to grassland or silage maize in the Netherlands

“…Since growth conditions largely determine the amount of grass N uptake, adverse growth conditions, such as drought, can decrease N uptake and rapidly increase nitrate leaching risk. Garwood and Tyson (1973) reported that when fertilizer N application to ryegrass, grown in lysimeters, increased from 250 to 500 kg N -1 ha year (Garwood and Roberts 1985). In this experiment, the annual N application rate was 420 kg N ha -1 and the grass was cut nine times.…”

Herbaceous layer development during spring does not deplete soil nitrogen in the Portuguese montado

“…In the Mediterranean region of Spain, which resembles the Portuguese montado, major organic matter input into the soil occurs during spring and summer while potential maximum nitrification is reached in spring, with a significant increase in soil extractable nitrogen between February and June (Gallardo et al, 2000). Low mineralization and soil N input in winter is due to low temperatures and anaerobic conditions (Whitehead, 1995), while nitrification is inhibited by dry soil conditions, restricting the amount of available N (Garwood and Tyson, 1973). Thus nitrogen input in spring should be adequate to support biomass development of the herbaceous layer without depleting the soil N store during spring and early summer, since the period also coincides with active mineralization and soil N input.…”