A collection beginning with consistently engaging essays loses its footing in the dreary fiction that follows, bringing Pulitzer Prize-winning poet Kumin's (In Deep, 1987, etc.) latest to a wobbly end. The poet in Kumin is fully evident in her essays. With florid, not fussy, prose and precise observation, she chronicles life on her New Hampshire farm, elevating jicama (``a delightfully crunchy root I first met on an hors d'oeuvres platter in Texas ten years ago'') to unforeseen heights and reaping life lessons from an adopted city mutt and spindle-legged fillies. She's both a student and a teacher, rapturously researching and relating details of the world: She compares half a dozen mushroom field guides in search of edible fungi and choice passages; readers will feel able to buy, train, and breed horses on finishing ``A Horse for Fun.'' Some essays are anecdotal (``Mutts'' is a comic dog tale); others are philosophical (``Have Saddle, Will Travel'' is about horseback riding possibilities on reading tours); still others resemble diary entries (``Labors of Love'' records foals' births in earthy prose). Her interest in the most mundane subjects (the squash leaves covering a dung heap), her compulsive devotion to nature (she sleeps alongside pregnant mares when their delivery dates approach), and her ability to translate life into language (should the dog's name scan as a trochee or a spondee?) are infectious. But the short stories are everything the essays are not: rushed, blunt, and vague. Dominated by domestic configurations--daughter meets young stepmom, hunter beds vegan, three generations of women welcome the fourth--their characters are bland and the telling dispassionate. Every point and meaning is stated--no room for reader imagination or inference here. The best stories are ``The Cassandra Effect,'' about a troubled graduate student, and ``Flotation Devices,'' in which three women are stranded while snorkeling. Antiseptic stories pale beside lush and verdant nonfiction: an unfortunate coupling.