Property, Plant and Equipment

As of August 31, 2019 and 2018, major classes of property, plant and equipment, which include capital lease assets, consisted of the amounts in the table below.



	2019		2018
	(Dollars in thousands)
Land and land improvements	$	319,452	$	341,767
Buildings	1,079,073		1,034,860
Machinery and equipment	7,392,767		7,199,509
Office equipment and other	346,649		316,946
Construction in progress	329,297		204,207
Gross property, plant and equipment	9,467,238		9,097,289
Less accumulated depreciation and amortization	4,378,530		3,955,570
Total property, plant and equipment	$	5,088,708	$	5,141,719

We have various assets under capital leases totaling $62.7 million and $50.0 million as of August 31, 2019 and 2018, respectively. Accumulated amortization on assets under capital leases was $20.6 million and $18.9 million as of August 31, 2019 and 2018, respectively.

The following is a schedule by fiscal year of future minimum lease payments under capital leases together with the present value of the net minimum lease payments as of August 31, 2019:



	(Dollars in thousands)
2020	$	6,761
2021	6,199
2022	5,021
2023	4,548
2024	2,638
Thereafter	6,517
Total minimum future lease payments	31,684
Less amount representing interest	3,445
Present value of net minimum lease payments	$	28,239

We continuously monitor our long-lived assets, including property, plant and equipment, for potential indicators of impairment in accordance with U.S. GAAP. As a result of these monitoring activities, our Ag segment recorded impairment charges of approximately $12.2 million associated with certain non-strategic long-lived assets that ceased operation during fiscal 2019. During fiscal 2017 our Ag segment recorded an impairment charge of $30.4 million from the reduction in the fair value of agricultural assets held, which was determined using a market-based approach. In addition, our Energy segment recorded an impairment charge of $32.7 million associated with the cancellation of a capital project in fiscal 2017. These impairments were included in the reserve and impairment charges (recoveries), net line of the Consolidated Statements of Operations.

Depreciation expense, including amortization of capital lease assets, for the years ended August 31, 2019, 2018 and 2017, was $495.3 million, $475.8 million and $475.9 million, respectively.