"The grass is flat and green, and the children cry in the clear night." What techniques are used and what feelings are rendered?

It's an anthropomorphic parting feeling.

From the fifth and sixth sentences of the Tang Dynasty poet Shen Quanqi, the full text of ancient poetry is as follows:

Walking alone for thousands of miles, lying high and lying on seven sides.

The mountain and the moon are near the window, and the Tianhe family is low.

Fangchun is flat and green, and Zigui cries at night.

Floating guests stay and listen, praise the city and smell the chicken.