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Two lysimeter experiments were conducted to quantify the effect of including plantain in pasture on nitrous oxide (N2O) emissions from cattle urine patches, as affected by urine deposition timing and soil type. In experiment one, two pasture types were tested: (i) perennial ryegrass (Lolium perenne)/white clover (Trifolium repens) (PRG/WC), and (ii) perennial ryegrass/white clover/plantain (Plantago lanceolata) (PRG/WC/P) pastures, under four urine application dates (late summer, early autumn, mid-autumn, and late autumn). In experiment two, two pasture types were tested: (i) PRG/WC and (ii) PRG/WC/P on two soil types (Balmoral shallow stony silt loam and Templeton deep stone-less silt loam). Both experiments applied cow urine (700 kg N ha−1) and collected gas samples using a closed chamber method. In experiment one and two, the addition of plantain to pasture had no significant effect on N2O-N emissions. Soil type had no significant effect on N2O-N emissions. However, urine application timing had a significant effect, with February having the highest average N2O-N emissions (9.0 kg N2O-N ha−1), followed by March (3.0 kg N2O-N ha−1), April (2.7 kg N2O-N ha−1) and May (1.7 kg N2O-N ha−1). This change in N2O-N emissions is attributed to cooler conditions reducing microbial activity, subsequently reducing nitrification and denitrification rates. [ABSTRACT FROM AUTHOR]

Nitrate (NO3−) leaching losses from lysimeters on a dairy farm were measured using an automated monitoring system designed to reduce labour and analysis costs. Nitrate leaching losses were measured under two soil types on farm (moderately deep and moderately shallow, stony silt loam) and under both urine patches and non-urine areas. The moderately deep soil leached significantly less NO3−-N than the relatively shallow soil in the 2016–17, 2017–18 and 2019–20 seasons. The NO3−-N leaching losses, under urine patches, were higher in autumn (168.5–190.1 kg NO3−-N ha−1) than in spring (3.7–4.9 kg NO3−-N ha−1) and summer (28.2–35.1 kg NO3−-N ha−1). Paddock scale NO3− leaching losses were calculated using a semi-empirical model. The calculated NO3−-N leaching losses ranged from 18.3 to 47.3 kg NO3−-N ha−1 year−1, with a mean loss of 30.7 kg NO3−-N ha−1 year−1. These relatively low leaching losses from free-draining dairy pasture soils may be due to the recent conversion from forestry to dairy, with the soil having a high soil C:N ratio that may have caused increased immobilisation and subsequently lower NO3−-N leaching loss. [ABSTRACT FROM AUTHOR]

Phosphorus losses from soils have been reported to impair the water quality, resulting in deaths of fish and other marine animals, and can harm human health. The objective of this study was to determine the seasonal distribution of P forms and losses in leachate collected from intact soil monoliths (70-cm depth, 50-cm diam.) of a Lismore stony silt loam soil (fine-loamy, mixed, superactive, frigid Aquic Cumulic Hapludoll) during a 2-yr period. The experiment included different combinations of mineral P fertilizer at 45 or 90 kg P [ha.sup.-1] [yr.sup.-1] and/or farm dairy effluent (FDE) at 200 or 400 kg N [ha.sup.-1] [yr.sup.-1], which contained 41 to 95 kg P [ha.sup.-1] [yr.sup.-1]. Amounts and forms of P in leachate collected daring the irrigation (IR; November-April) and nonirrigation (NIR; May-October) seasons were compared. Results showed that P losses were higher in particulate forms (mainly particulate unreactive phosphorus, PUP) during the IR seasons. This may be because of regular inputs of high intensity flood IR (92 mm per application), which increased the dislocation of particles in the soil profile, thereby resulting in higher PUP losses. On the other hand, the amount of natural rainfall was much lower (usually

A lysimeter experiment using undisturbed monoliths from a stony silt loam soil was carried out to quantify the effects different pasture types on N losses from urine applied to soil on different dates. Three pasture types were tested: (a) perennial ryegrass (Lolium perenne)/white clover (Trifolium repens) (PRG/WC), (b) perennial ryegrass/white clover/plantain (Plantago lanceolata) (PRG/WC/P) and (c) Italian ryegrass (Lolium multiforum)/white clover/plantain (IRG/WC/P), with four different urine applications dates (late summer, early autumn, mid‐autumn and late autumn). Cattle urine was applied at the equivalent of 700 kg N−1 ha−1. There was a significant reduction in total amount of nitrate (NO3−‐N) leached under the PRG/WC/P (14% reduction) and IRG/WC/P (24% reduction) compared with the PRG/WC. High NO3−‐N leaching losses were found at each urine application date (>181 kg NO3−‐N/ha), suggesting there may be higher than expected N leaching losses when urine is deposited onto shallow stony soils, during warmer months (late summer and early autumn). There was no significant interaction between pasture type and urine timing on NO3−‐N leaching losses. [ABSTRACT FROM AUTHOR]

A lysimeter experiment was conducted to investigate the environmental effects of applying farm dairy effluent (FDE) treated with a chemical coagulant (polyferric sulphate) to land. The coagulant was administered as part of an effluent treatment system known as ClearTech. Two products are produced from the treatment process; treated effluent (TE) and clarified water (CW). Applications were applied in May. When compared to FDE, TE and CW reduced E. coli, Total-P and dissolved reactive P (DRP) leaching losses. Escherichia coli leaching losses were reduced by 99.97% and 99.99% for TE and CW, respectively. This was because of the acidity of the added coagulant and the encapsulation of the bacteria in the flocculated sediment. Compared to FDE, Total-P leaching losses were reduced by 90.5% and 85.7% for TE and CW, respectively. DRP leaching losses were also reduced under TE and CW by 99.5% and >99.99%, respectively. Reductions in phosphorus leaching were attributed to the reduced P solubility, resulting from the iron added in the coagulant binding to the phosphorus. There was no significant difference between treatments in the amount of iron leached, greenhouse gas emissions or Mineral-N leached (except where additional ammonium-N was added to the clarified water). [ABSTRACT FROM AUTHOR]

Future development pathways for irrigated dairy farms in Canterbury operating under stricter nitrogen (N) loss limits were compared in two farmlets over four years. One represented the traditional pathway of intensification via higher inputs of N fertiliser and supplementary feed ('higher input-high efficiency', HI-HE), while the other represented a lower input pathway using half the amount of N fertiliser and one quarter the amount of supplementary feed ('lower input-high efficiency', LI-HE). The stocking rate of both systems was matched to feed supply to achieve high utilisation (∼90%) of the pasture grown. Mean total annual N surplus and estimated nitrate-N leaching were lower in LI-HE than HI-HE, by 46% and 25% respectively. Milk production was lower for LI-HE (1,700 kg versus 2,240 kg milk fat + protein per ha/year). Estimated profit was the same for both systems at a milk price of $6.46/kg fat + protein, below which LI-HE was more profitable than HI-HE and vice-versa. Compared with the benchmark high-performing Lincoln University Demonstration Dairy Farm (LUDF) through the same period, LI-HE was 2% less profitable, but estimated N leaching was ∼30% lower. Subsequent adoption of the LI-HE system by LUDF demonstrated that the system is scalable, and profitable. [ABSTRACT FROM AUTHOR]

A lysimeter experiment was carried out to investigate the effects of applying readily available carbon (12 or 24 t sucrose ha−1) to soil on nitrogen (N) losses from cattle urine patches. The carbon (C) was readily available to microbes and was applied onto intact soil monolith lysimeters, containing stony silt loam soil, beneath either ryegrass (Lolium perenne)/white clover (Trifolium repens) pasture (RG/WC) or lucerne (Medicago sativa). Cow urine (700 kg N ha−1) was applied in early July 2017, two days after C application. The application of readily available C increased the immobilisation of N in the soil which reduced the amount of soil mineral N. The C-induced immobilisation of N reduced the ammonia oxidising bacteria population growth rate and the amount of nitrate leached by 51–89%. The addition of readily available C had no significant effect on nitrous oxide emissions. These findings were consistent under both RG/WC and lucerne. [ABSTRACT FROM AUTHOR]