A piece of hallowed ground in Belgium which holds in its grasp the remains of hundreds of New Zealand soldiers is still claiming victims a century after World War One. Unexploded bombs and grenades buried under thick mud in the Battle of Passchendaele in 1917 get pushed to the surface in hard European winters, and pose deadly threats to farmers working land where scores of New Zealanders died in grim conflicts on the Western Front. Lode Notredame, who grew up in Passchendaele village, said the 100-year-old war material created three or four casualties a year. As a boy, he retrieved rifles, pistols, ammunition and helmets which surfaced long after the war. "Every year 200 tonnes of war relics are collected," Notredame told the Herald. "We call it the iron harvest or the harvest of death." For farmers, the most menacing hazards were gas shells which in the Great War rained down on Allied forces from German artillery positions. "The farmers have to run away upwind in case they go off, " Notredame said. Live grenades were a danger to contractors using potato harvesters. The machines dug up field crops, and old explosives could be concealed in the vegetables, posing a deadly threat to workers grading the crop and mistakenly handling a dirt-caked device. Notredame said farmers had taken the precaution of reinforcing tractors with steel bottom plates, shielding drivers in the event of a blast. Apart from long-buried ordnance, human remains were still recovered from the battlefields, and treated with care and dignity. But unless identifying items such as badges or distinctive uniforms were found it was impossible to say whether the war remains belonged to a soldier serving with Allied or enemy forces. New Zealand lost at least 1900 troops in the 1917 Ypres offensive, as British commanders threw soldiers in a knuckle-shaped push from the front line deeper into Belgium. Casualties on both sides were immense, with the toll from Battle for Passchendaele casting a pall over New Zealand. A sense of the enormous sacrifice is illustrated by the number of memorials built around the Flanders region. The largest is Tyne Cot Cemetery, which sits on the strategic high ground held by the Germans and from where machine gunners and artillery units operated with deadly efficiency. There are 520 graves of New Zealanders at Tyne Cot, 322 of them unidentified. A separate part of the memorial called the New Zealand Apse commemorates 1176 New Zealanders who have no known grave. Just a few kms away to the south, a memorial to the missing in the Buttes New British Cemetery has the names of 383 New Zealanders, with 167 buried in the cemetery. Many of Passchendaele casualties occurred in a single day. The action on Bellevue Spur, a gentle slope which runs up towards Passchendaele village, cost the New Zealand Division a staggering 846 men on 12 October 1917. More died that day than on any other in New Zealand's military history and for many critics the disaster summed up the horror, waste and futility of the Western Front conflict. Appalling weather meant attacking forces struggled to get big guns into place where they could pound enemy locations. Heavy batteries dragged into position lacked ammunition to keep up the assault. When they did fire, they sank into the quagmire, affecting their accuracy and range. German defences, protected by thick tangles of barbed wire, were barely penetrated. In the days after the catastrophe, yet more soldiers succumbed to their injuries, some caused by artillery barrages which tore apart the New Zealanders instead of the enemy. Bitter recriminations followed the tragedy at Passchendaele, with senior New Zealand military officers scathing in their views of British commanders. The war diary of Brigadier-General Napier Johnston, who was in charge of an artillery brigade, called it "nothing but a slaughter." General Alexander Godley, the Sandhurst-trained head of the New Zealand Expeditionary Force, came under fierce attack for failing to delay the October 12 battle, though he was sticking to the plan dictated by his commander-in-chief, Sir Douglas Haig, who was determined to capture Passchendaele. A British military historian J.F.C. Fuller, wrote: "To persist...in this tactically impossible battle was an inexcusable piece of pigheadness on the part of Haig." Belgium-born Lode Notredame, who has taken New Zealanders on battlefield tours of the Ypres region and now takes tourists around this country, said the huge World War One losses forged an enduring bond between the two countries. At the time of the Passchendaele conflict the Belgium Army was engaged at Nieuport, about 50kms away towards the English Channel. "People in Belgium are extremely grateful that people from the uttermost end of the earth came to fight for our freedom," he said. "People also want to come here to see where the soldiers who put up those horrible conditions came from. "