Performance of APSIM to Simulate the Dynamics of Winter Wheat Growth, Phenology, and Nitrogen Uptake from Early Growth Stages to Maturity in Northern Europe.

Performance of the APSIM (Agricultural Production Systems sIMulator) wheat model was assessed to simulate winter wheat phenology, biomass, grain yield, and nitrogen (N) uptake for its potential to optimize fertilizer applications for optimal crop growth and minimal environmental degradation. The calibration and evaluation dataset had 144 and 72 different field growing conditions (location (~7) × year (~5) × sowing date (2) × N treatment (7-13)), respectively, and included seven cultivars. APSIM simulated phenological stages satisfactorily with both model calibration and evaluation data sets with r of 0.

S-map parameters for APSIM.

Agroecosystem models have become an important tool for impact assessment studies, and their results are often used for management and policy decisions. Soil information is a key input for these models, yet site-specific soil property data are often not available, and soil databases are increasingly being used to provide input parameters. For New Zealand, the digital spatial soil information system S-map provides geospatial data on a range of soil characteristics, including estimates of soil water properties.

A protocol to build soil descriptions for APSIM simulations.

Soil processes have a major impact on agroecosystems, controlling water and nutrient cycling, regulating plant growth and losses to the wider environment. Process-based agroecosystem simulation models generally encompass detailed descriptions of the soil, including a wide number of parameters that can be daunting to users with a limited soil science background. In this work we review and present an abridged description of the models used to simulate soil processes in the APSIM (Agricultural Production Systems sIMulator) framework.

Mineralisation of catch crop residues and N transfer to the subsequent crop.

Catch crops (CC) are widely used to reduce nitrogen leaching from arable cropping systems. However, the mineralisation rate of different catch crop species, and the fate of the mineralised N remain unclear. In this study, we performed an analysis, based on N mineralisation incubation experiments, to test and parameterise a simple mineralisation model (SMM), based on a first order decay, for different catch crops.

Simulation of management strategies to mitigate nitrogen losses from crop rotations in Southland, New Zealand.

Background: Nitrogen (N) fertiliser used on crops is among the main sources of water pollution. Reliable measurement of N losses from land uses in catchments is key to designing effective management strategies that minimise those losses at the same time as keeping farms profitable. In the present study, we used a management simulation tool within the Agricultural Production Systems sIMulator (APSIM) to assess the effect of fertiliser management on N leaching from croplands in the Aparima catchment in Southland, New Zealand.

Nitrate leaching from suction cup data: Influence of method of drainage calculation and concentration interpolation.

The use of suctions cups is a common practice for estimating nitrate (NO -N) leaching under agricultural systems despite the various uncertainties associated with the approach. One major uncertainty is water flux, which is required for calculating NO -N leaching loads from measured concentrations. Another problem is the interpolation of NO -N concentrations between measurement days.

Yield Progress in Forage Maize in NW Europe-Breeding Progress or Climate Change Effects?

Yield increases in forage maize (Zea mays L.) in NW Europe over time are well documented. The driving causes for these, however, remain unclear as there is little information available regarding the role of plant traits triggering this yield progress.

Legumes in catch crop mixtures: Effects on nitrogen retention and availability, and leaching losses.

Catch crop (CC) mixtures of non-legumes (nL) and legumes (L) have been promoted as a strategy to achieve two different goals: to decrease the risk of nitrate leaching and to enhance the nitrogen supply to the subsequent crop. To investigate if two-component mixtures of nL + L have advantages over pure nL stands experiments were carried out over a two year period (2013-2015) at two contrasting field sites in Denmark. Nitrogen (N) uptake by the CCs was measured by aboveground biomass sampling, and N leaching by ceramic suction cups.

Long-chain n-alkane and n-fatty acid characteristics in plants and soil - potential to separate plant growth forms, primary and secondary grasslands?

Plant-derived lipid molecular proxies can provide insight into present-day soil carbon input and to what extent organic carbon is degraded within soil. To explore whether soil characteristics of 'primary' (i.e.

Lateral spread affects nitrogen leaching from urine patches.

Nitrate leaching from urine deposited by grazing animals is a critical constraint for sustainable dairy farming in New Zealand. While considerable progress has been made to understand the fate of nitrogen (N) under urine patches, little consideration has been given to the spread of urinary N beyond the wetted area. In this study, we modelled the lateral spread of nitrogen from the wetted area of a urine patch to the soil outside the patch using a combination of two process-based models (HYDRUS and APSIM).

The effect of drought and nitrogen fertiliser addition on nitrate leaching risk from a pasture soil; an assessment from a field experiment and modelling.

Background: A combination of field experiment and modelling tested the hypothesis that dry summers increase the risk of nitrogen (N) leaching from pasture owing to a combination of: soil N accumulation in a dry summer; slow recovery of drought-affected pasture in the autumn; and the resultant inefficient use of fertiliser N by the pasture.

Results: In the experiment, pasture response to urea and apparent N recovery in autumn after the drought was half that of irrigated pasture (7 vs 13 kg dry matter kg N; 28 vs 52% apparent recovery; P < 0.05).

Combining Restricted Grazing and Nitrification Inhibitors to Reduce Nitrogen Leaching on New Zealand Dairy Farms.

Intensification of pastoral dairy systems often means more nitrogen (N) leaching. A number of mitigation strategies have been proposed to reduce or reverse this trend. The main strategies focus on reducing the urinary N load onto pastures or reducing the rate of nitrification once the urine has been deposited.

Effect of inter-annual variability in pasture growth and irrigation response on farm productivity and profitability based on biophysical and farm systems modelling.

Farm system and nutrient budget models are increasingly being used in analysis to inform on farm decision making and evaluate land use policy options at regional scales. These analyses are generally based on the use of average annual pasture yields. In New Zealand (NZ), like in many countries, there is considerable inter-annual variation in pasture growth rates, due to climate.

A regional assessment of the cost and effectiveness of mitigation measures for reducing nutrient losses to water and greenhouse gas emissions to air from pastoral farms.

Using a novel approach that links geospatial land resource information with individual farm-scale simulation, we conducted a regional assessment of nitrogen (N) and phosphorous (P) losses to water and greenhouse gas (GHG) emissions to air from the predominant mix of pastoral industries in Southland, New Zealand. An evaluation of the cost-effectiveness of several nutrient loss mitigation strategies applied at the farm-scale, set primarily for reducing N and P losses and grouped by capital cost and potential ease of adoption, followed an initial baseline assessment. Grouped nutrient loss mitigation strategies were applied on an additive basis on the assumption of full adoption, and were broadly identified as 'improved nutrient management' (M1), 'improved animal productivity' (M2), and 'restricted grazing' (M3).

Modelling pastoral farm systems--scaling from farm to region.

Farm system and nutrient budget models are increasingly being used to inform and evaluate policy options on the impacts of land use change on regional environmental and economic performance. In this study, the common approach of up-scaling representative farm systems to a regional scale, with a limited input of resource information, was compared with a new approach that links a geospatial land resource information data base (NZLRI, Agribase™) that includes independent estimates of the productive capacity of land parcels, with individual farm-scale simulation (Farmax® Pro and Farmax® Dairy Pro) and nutrient budgeting models (Overseer®). The Southland region of New Zealand, which is currently undergoing enormous land use change, was used as a case study.

Identification and testing of early indicators for N leaching from urine patches.

Nitrogen leaching from urine patches has been identified as a major source of nitrogen loss under intensive grazing dairy farming. Leaching is notoriously variable, influenced by management, soil type, year-to-year variation in climate and timing and rate of urine depositions. To identify early indicators for the risk of N leaching from urine patches for potential usage in a precision management system, we used the simulation model APSIM (Agricultural Production Systems SIMulator) to produce an extensive N leaching dataset for the Waikato region of New Zealand.

A new method to quantify the impact of soil carbon management on biophysical soil properties: the example of two apple orchard systems in New Zealand.

A new method to diagnose the environmental sustainability of specific orchard management practices was derived and tested. As a significant factor for soil quality, the soil carbon (C) management in the topsoil of the tree-row of an integrated and organic apple orchard was selected and compared. Soil C management was defined as land management practices that maintain or increase soil C.

Mobility of copper, chromium and arsenic from treated timber into grapevines.

The use of chromated copper arsenate (CCA) treated timber posts as support structures in New Zealand vineyards has raised concerns regarding the release of heavy metal(loid)s from the treated timber into the environment. A laboratory experiment was set up to evaluate if post sealing by painting reduces the release rate of CCA metal(loid)s from timber posts. Three posts were painted (Gripset 38, Multi Purpose Bitumen Rubber) on the bottom part, submerged in freshwater, and the concentrations of copper (Cu), chromium (Cr) and arsenic (As) in the water were monitored over a period of 8 months.

Phytoremediation and long-term site management of soil contaminated with pentachlorophenol (PCP) and heavy metals.

Pentachlorophenol (PCP) is a persistent organic pollutant (POP) previously used as a timber treatment chemical to prevent sap stain and wood rot. Commonly used in wood treatment industries for the last 50 years, there are now many sites worldwide that are contaminated with PCP. Although persistent, PCP is a mobile contaminant and therefore has a propensity to leach and contaminate surrounding environments.

Imaging of water flow in porous media by magnetic resonance imaging microscopy.

Magnetic resonance imaging (MRI) was used to study the flow of water in a column 14 mm in diameter packed with glass heads. The sample was fully saturated and water was pumped through the column using a peristaltic pump, at flow rates of 125 and 250 mL h(-1). This corresponds to mean velocities of 0.