相关规则
Australia
Practice Relating to Rule 54. Attacks against Objects Indispensable to the Survival of the Civilian Population
Section C. Attacks in case of military necessity
Australia’s Commanders’ Guide (1994) provides:
The ADF [Australian Defence Force] may not embark on a scorched earth policy within Australia or its territories unless under their control at the time of devastation and driven by imperative military necessity. It is still permitted, for example, to destroy a wheat-field to deny concealment to enemy forces. 
Australia, Law of Armed Conflict, Commanders’ Guide, Australian Defence Force Publication, Operations Series, ADFP 37 Supplement 1 – Interim Edition, 7 March 1994, § 908.
Australia’s Defence Force Manual (1994) states:
It is permissible to destroy objects which are indispensable to the survival of the civilian population in the course of ordinary military operations only if it is militarily imperative to do so, for example to destroy a wheat field to deny concealment to enemy forces, because this is a tactical measure and does not amount to a scorched earth policy. The ADF [Australian Defence Force] may embark on a scorched earth policy in territory under Australian control where imperative military necessity requires it to do so to protect Australian national territory from invasion. 
Australia, Manual on Law of Armed Conflict, Australian Defence Force Publication, Operations Series, ADFP 37 – Interim Edition, 1994, § 712; see also § 931(c).
Australia’s LOAC Manual (2006) states:
7.13 It is permissible to destroy objects which are indispensable to the survival of the civilian population in the course of ordinary military operations only if it is militarily imperative to do so, for example, to destroy a wheat field to deny concealment to enemy forces, because this is a tactical measure and does not amount to a scorched earth policy.
9.32 … Objects indispensable to the survival of the civilian population are excluded from protection if … the military necessity for the defence of territory against invasion so requires. 
Australia, The Manual of the Law of Armed Conflict, Australian Defence Doctrine Publication 06.4, Australian Defence Headquarters, 11 May 2006, §§ 7.13 and 9.32.
The LOAC Manual (2006) replaces both the Defence Force Manual (1994) and the Commanders’ Guide (1994).