For the six months to 31 March pre- tax profits dived from pounds 109m to pounds 38m.
'We have been buffeted by the economic climate and by depressed commodity prices, but Lonrho's wide range of businesses has enabled the group to remain profitable and strong,' Mr Rowland has told shareholders.
He said that since January Lonrho had sold or contracted to sell peripheral businesses which would realise pounds 500m. The sales are designed to reduce group debt, which at the beginning of the year stood at pounds 1.4bn.
'Borrowings at 31 March were pounds 903m, with future meaningful reductions before the end of the financial year as the disposal programme is realised,' he added.
Although Lonrho refused to confirm what businesses might be disposed of, the sale of engineering businesses in the UK and of a holding company which owns 4,300 flats in Germany are 'possibilities', according to the joint deputy chairman Paul Spicer.
Mr Rowland said that the largest sale so far had been Lonrho's controversial deal with the investment agency of the Libyan government.
In March this year Lonrho sold a third stake in its Metropole Hotel chain for pounds 177.5m to the Libyans in spite of worldwide outrage over Libya's alleged involvement in terrorism.
There has been widespread speculation that Lonrho had passed control of the hotel chain over to the Libyans in a move that would have compromised the position of Lonrho's second bgiggest shareholder, the US-based Fidelity Management and Research, which has a near 10 per cent stake.
Fidelity might have been forced to sell its holding as a result of US policy towards Libya.
'The share issue does not contravene either the United Nations limited economic sanctions or the US directive on Libyan investments,' Mr Rowland has told shareholders. The deal, he added 'has the approval of the Department of Trade and Industry in the UK'.
'We are in control at Metropole,' said Mr Spicer. 'We took advice from the American and British foreign departments.'
Mr Rowland said that the pounds 177.5m derived from the sale of the Metropole stake was banked in London. 'As a result the Metropole chain chose to clear borrowings and substantially improve profitability,' he added.
According to Lonrho pounds 100m has been spent in expanding successful businesses within the group 'to underpin future growth and profit'.
Mr Rowland said that the group intended to pay out a much reduced half year dividend to shareholders of 2p compared with the 8p that had been paid by this stage a year ago.
On the group's important African mining interests, Mr Rowland said that low prices in the first half and some processing problems at the smelter complex had badly dented profits.
But on a brighter note he continued: 'With throughput back to normal, the second half looks set to see a substantial increase in the contribution to the group from the world-class mines of Western Platinum.'
For the full year ending in September City analysts expect Lonrho to report pre-tax profits of between pounds 100m and pounds 125m compared with pounds 207m in the previous financial year.
Mr Spicer said: 'This is a year of good housekeeping for Lonrho. We are cleaning up and climbing back.'
On the stock market the share price rose 1p to 78p.