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Plant available soil water at sowing in Mediterranean environments - is it a useful criterion to aid nitrogen fertiliser and sowing decisions?


Moeller, C and Asseng, S and Berger, J and Milroy, SP, Plant available soil water at sowing in Mediterranean environments - is it a useful criterion to aid nitrogen fertiliser and sowing decisions?, Field Crops Research: An International Journal, 114, (1) pp. 127-136. ISSN 0378-4290 (2009) [Refereed Article]

Copyright Statement

Crown copyright 2009 Published by Elsevier B.V

DOI: doi:10.1016/j.fcr.2009.07.012


In regions where rainfall is low and variable, water stored in the soil profile prior to sowing can alter yield expectation and hence management decisions. Thus, wheat farmers in Mediterranean regions may be able to benefit from knowing the amount of soil water at sowing by optimising their nitrogen (N) fertiliser management and by deciding on whether or not to sow a crop. We used the ASPIM-Nwheat model to explore how levels of plant available soil water (PAW) at sowing, N fertiliser rate, soil, site and season-type (below or above median rainfall) affected wheat yields at sites in theMediterranean area of southwest Australia. Overall, the greatest influence on yield potential and the consequent N fertilisation requirement was season-type. The additional yield per mm PAW at sowing was generally higher in seasons with below median rainfall, except when yields were severely water-limited by below median rainfall of <222 mm combined with <40 mm PAW at sowing on light clay soil with 109 mm plant available water capacity (PAWC). Sowing was generally warranted; only on light clay soil with <10 mm PAW at sowing and below median rainfall of <222 mm was there an opportunity for a conditional sowing strategy. Scope for varying N fertiliser rates with PAW at sowing was limited to soils with higher PAWC (109 and 130 mm, respectively) in below median rainfall seasons at the wetter site (295 mm mean seasonal rainfall), and in both season-types at the drier site (225 mmmean seasonal rainfall). Only in these combinations, soil water at sowing modified the optimal N fertiliser rate for maximum average yield resulting in significant interactions between PAW at sowing and N fertiliser rates. Similar interactions were found for a site in the Mediterranean Basin and a site in the eastern Australian subtropics on soil with high PAWC (183 and 276 mm, respectively). In contrast, there was no benefit from modifying crop management based on PAW at sowing on soil with low PAWC (i.e. sandy soil) and/ or under conditions of high in-season rainfall. The conditional N management approach becomes more viable as the proportion of water stored in the soil prior to sowing increases relative to total crop water use and as the PAWC of the soil increases. Knowledge of PAW at sowing  N fertiliser rate interactions in a particular soil  site  season-type context can help to identify sites where a more targeted N management dependent on amounts of PAW at sowing is potentially profitable.

Item Details

Item Type:Refereed Article
Keywords:wheat, nitrogen, sowing, plant available soil water at sowing, seasonal rainfall, simulation modelling
Research Division:Agricultural, Veterinary and Food Sciences
Research Group:Crop and pasture production
Research Field:Agronomy
Objective Division:Plant Production and Plant Primary Products
Objective Group:Environmentally sustainable plant production
Objective Field:Environmentally sustainable plant production not elsewhere classified
UTAS Author:Moeller, C (Dr Carina Moeller)
ID Code:84293
Year Published:2009
Web of Science® Times Cited:38
Deposited By:Agricultural Science
Deposited On:2013-05-03
Last Modified:2016-09-27

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