Property, Plant and Equipment

As of August 31, 2017, and 2016, major classes of property, plant and equipment, which include capital lease assets, consisted of the amounts in the table below.



	2017		2016
	(Dollars in thousands)
Land and land improvements	$	357,829	$	266,016
Buildings	1,030,478		1,040,943
Machinery and equipment	6,950,435		6,747,865
Office and other	235,361		250,879
Construction in progress	327,682		523,817
	8,901,785		8,829,520
Less accumulated depreciation and amortization	3,545,351		3,341,197
Total property, plant and equipment	$	5,356,434	$	5,488,323

We have various assets under capital leases totaling $58.2 million and $206.3 million as of August 31, 2017, and 2016, respectively. Accumulated amortization on assets under capital leases was $27.4 million and $103.3 million as of August 31, 2017, and 2016, respectively. During the fourth quarter of fiscal 2017, we completed a buyout of various capital leases for approximately $39.6 million. The various capital leases represented approximately 58% of our total capital lease obligations.

The following is a schedule by fiscal years of future minimum lease payments under capital leases together with the present value of the net minimum lease payments as of August 31, 2017:



	(Dollars in thousands)
2018	$	6,867
2019	6,150
2020	4,728
2021	4,525
2022	3,945
Thereafter	13,285
Total minimum future lease payments	39,500
Less amount representing interest	6,425
Present value of net minimum lease payments	$	33,075

We announced in September 2014 that our Board of Directors had approved plans to begin construction of a fertilizer manufacturing plant in Spiritwood, North Dakota that was anticipated to cost more than $3.0 billion. In August 2015, we made the decision to not move forward with the construction of the Spiritwood facility and evaluated the assets and other capitalized costs related to the project for recoverability under ASC Topic 360-10. Consequently, we concluded that these assets were impaired and we recorded an overall charge of $116.5 million in reserve and impairment charges in our Ag segment. This charge was primarily comprised of the impairment of construction-in-progress, land and equipment totaling $94.3 million. The remainder of the charge included the impairment of other assets and various contract termination costs associated with the cessation of the project.

During the fourth quarter of fiscal 2017 our Ag segment recorded an impairment charge of $30.4 million, which is included in the reserve and impairment charges line of the Consolidated Statements of Operations. The impairment resulted from the reduction in the fair value of agricultural assets held, which was determined using a market based approach.

Depreciation expense, including amortization of capital lease assets, for the years ended August 31, 2017, 2016, and 2015, was $475.9 million, $437.6 million and $344.4 million, respectively.