Alfalfa-Oat-Clorer Pasture for Dairy Cattle


 RESULTS
 Rainfall and Irrigation Water Applied.-Precipitation was
 subnormal during each of the first three pasture seasons, and
 was quite deficient in some periods. Rainfall was 7 inches be-
 low normal (1931-55 average) in the 1954-55 grazing season.
 Low soil moisture influenced pasture yield particularly during
 late spring and summer.
 In the 1955-56 growing season precipitation totaled 31 inches,
 which was 21 inches below normal. The irrigated pasture re-
 ceived three applications of water prior to initiation of grazing
 and 11 during the grazing season for a total of 15.1 inches. Rain-
 fall was unusually low in late 1956 and early 1957. Nine irriga-
 tions supplying 11.3 inches of water were made prior to initia-
 tion of grazing, and 9 inches of water were applied in seven ir-
 rigations during the 1957 grazing season.
 Precipitation was 3 inches above normal for the 1959-60 sea-
son, and the pasture did not appear to suffer from insufficient
soil moisture. Heavy rains in June waterlogged the soil, and
this appeared to have retarded growth of the alfalfa. The
amounts and distribution of rainfall are shown in Figure 1.
 Grazing Periods and Total Digestible Nutrients Obtained
per Acre.-Grazing was initiated on unirrigated pastures from
November 17 to January 12, except in 1956, when it was de-
layed until April 20 by drought, disease, and cold weather. The
intervals from plantings until grazing ranged from 56 to 82
days, except for 1955-56, when it was 147 days. Short inter-
vals between seeding and grazing were associated with mild
weather and adequate soil moisture.
 The four grazing seasons on unirrigated pasture averaged
202 days in length and were continuous in 1957 and 1960. There
was a seven-day interruption due to dry weather and disease in
1954-55 and two interruptions totaling 90 days caused by cold
and/or dry weather in 1955-56. Grazing was concluded in mid-
September of two years in order to prepare the land for reseed-
ing. Termination of grazing in mid-August and mid-July the
other two years was caused by slow growth and a poor stand
of attenuated alfalfa plants due to diseases.
 Calculated amounts of total digestible nutrients (1) obtained
per acre from unirrigated pasture averaged 4,585 pounds per
acre for four years and ranged from 1,670 to 7,098 pounds per
year.