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An additional 50 pounds per acre of N were appliad to the established grasses in the spring of 1956. The plots have been irrigated at weekly intervals. Yields of the replicated varieties (N-lto N-20) were taken in 1955. Tillage-Reclamation Plots (Large Field Plots) The tUlage-reclamation plots were established in 1956. The general design and plot treatuents are shown in Figure 2. The treatments are: (l) 36-inch plowing with and without an application of 1 ton per acre of gypSUlll in areas w.i.th a "pan" and without a "pan," (2) 4 to 5-inch plowing with and without an application of 1 ten per acre of gypsum in areas with a "pan" and without a "pan," and (3) 36-inch chiselling with and without an application of 1 ton :Jer al.lre of gypSUlll in areas with a "pan" and without a "pan." - Each plot is 30 feet wide and 100 feet long. All plots were leached with 28 acre-inches of water. A uniform application of 300 pounds per acre of P2q~ fertilizer was made. The plots were seeded to Ranger alfalfa in July 1956. The plots will be both surface and sub-irrigated. YIELD RESULTS Main Reclamation Plots (Plots 1 - 96) The 1955 barley grain "yields are shown in Table I on page ll. The greatest difference.s in yields were associated with the effects of the water table levels. The average of the 1955 barley grain yields on the subbed plots (l3.7 bU./A.) was approximately twice the yield on the drained plots (7.9 bu./A.). Higher ;jtields were obtained from the addi- tion of chemical amendments on the sub-irrigated plots. On the drained plots little difference in yields was obtained from the addition of amendments or rates of amendments. After 4 years of cropping little difference in barley grain yields was l' ound between plots which had re- ceived 2l acre-inches and 30 acre-inches of leaching water. No increase in barley grain yields was obtained from the high rate of irrigation on the drained plots. Barley yields were increased somewhat by the high rate of surface irrigetion on the sub-irrigated plots. The law yield of barley grain was due te severe bird damage and late frosts. The yield results from the 1956 first cutting of alfalfa are shown in Table II. The alfalfa yields are influenced markedly by the stand obtained on the plots. Poor stands of alfalfa were obtained on the plots which received the low rate of surface irrigation in both the drained and sub-irrigated areas. Both the stand and yields of alfalfa are better, generally, in the sub-irrigated area. Highest yields were obtained from plots which received the higher rate of chemical amendments. In the sub- irrigated area higher yields are also asscciated with plots which originally had received 30 acre-inches of leaching water. -9- f"','-'"",,,, J ; . ' . -"I ~ J '. ~'" ~..... ~.