JINAN, China, June 21 (Reuters) - After weeks of scorching heat and little rain, farmer Zhang Yunjing had no choice but to collect water from a wastewater pipe to irrigate her parched corn field in China's eastern Shandong province.

Zhang would normally use water from a nearby river for the half hectare (1.24 acre) field, but it dried up a month ago.

Record high temperatures have swept across northwest and east China, a key grain producing region, during the crucial corn sowing season, threatening to curb production in the world's second-largest producer and consumer of the grain.

"There is no water," Zhang said. "Look, people are going to other villages to collect water. Seeds are not sprouting without water."

China, also the world's No. 1 corn importer, produced a record 288.8 million metric tons last year and aims to grow more to achieve food security, but climate shocks are posing big challenges.

The agriculture ministry warned this week that the drought is impacting the sowing and growth of new crops. Beijing has allocated 443 million yuan ($61.1 million) for drought prevention work such as watering, replanting and adding fertiliser in seven provinces.

Lower grain output in the world's top cereal importer will encourage higher purchases from exporters such as Brazil, the United States and Argentina, underpinning global prices and food inflation.

The seven, drought-hit provinces account for roughly 35% of China's corn production, although some areas are likely to escape severe damage because they have irrigation capacity.

The heat hit Shandong, a major agricultural province, just as farmers were wrapping up their wheat harvest, damaging some of the ripened grain.

Shandong has planted over 3.32 million hectares of corn so far this season, as well as 78,000 hectares of corn and soybean intercrop planting. That compares with 3.29 million hectares of corn and 79,933 hectares of intercrop planted by the same time last year.

Near the capital Jinan, farmers are finding ways to mitigate the drought as they start to sow corn.

Some growers told Reuters that they are delaying planting to avoid the gruelling heat but still expect a poor harvest this year.

Despite pushing back his corn sowing from June 5 to June 20, Chen Fuling said his seeds will struggle to sprout due to the dry soil.

"We will not have a good harvest this year," he said.

Some seedlings that have sprouted are showing signs of heat stress.

"There was no water in the river. I can only mix pesticide with tap water," another farmer Wang Cuiping said.

China's emergency management ministry has asked people in the drought-hit regions, including northwestern Shaanxi, northern Hebei and Shanxi, eastern Anhui and Shandong as well as central Henan, to protect water and food production.

Analysts said the drought, if prolonged, will impact freshly emerged seedlings, but a bigger concern is the upcoming La Nina weather pattern which typically brings heavy rain to the region and may damage crops.

La Nina is expected to emerge in late summer, usually the end of September, according to China's meteorological department.

The summer corn crop is typically harvested around October.

"The drought did have some impact on corn planting but it is not a big problem now because the irrigation system is very effective in most areas of North China," said Rosa Wang, analyst at Shanghai-based agro-consultancy JCI.

Near Zhang's farm, where many small plotholders still rely on manual watering, a group of sweat-drenched farmers braved the heat to repair a well that had been unused for over 30 years. They attempted to add a high-pressure water pump to draw water from underground.

"Every year after the wheat harvest is done, it usually rains within 10 days. It has been 20 days and the rain has not fallen," Jiang Xueyuan said.

"We have planted the corn too late, even after the autumn, it will not mature in time. The money for seeds and pesticides will be wasted." (Reporting by Xihao Jiang, Nicoco Chan and Mei Mei Chu; Editing by Naveen Thukral and Kim Coghill)