EFFECT OF DRIP IRRIGATION SCHEDULES AND SOIL MULCHING ON TUBER YIELD OF POTATO (Solanum tuberosum L.) VAR. SPUNTA

Two field experiments were carried out to find out the “Effect of drip irrigation schedules and mulching on growth and tuber yield of Potato (Solanum tuberosum L.) Var. Spunta grown on sandy loam soils at Balteem, Kafr El – Sheikh Governorate, Egypt during winter seasons of 2005-2006 and 2006-2007. Six treatments combinations involving two drip irrigation regimes (I₁: 60% ETo and I₂: 80% ETo) in main plots and three kinds of mulch (M₀: No mulch, M₁: Organic mulch and M₂: Plastic mulch) in sub plots were tested in a split-plot design with four replications.
Tuber yield obtained was significantly higher with the drip irrigation regime of 80% ET₀ (52.0 t/ha in 2005-06 and 48.2 t/ha in 2006-07) as compared to 60% ET₀ (47.2 t/ha in 2005-06 and 43.4 t/ha in 2006-07).
Use of black polyethylene mulch resulted in significantly higher yield of tubers (53.7 t/ha in 2005-06 and 49.8 t/ha in 2006-07) as compared to rice straw mulch (50.6 t/ha in 2005-06 and 46.6 t/ha in 2006-07) and no mulch (44.5 t/ha in 2005-06 and 41.0 t/ha in 2006-07).
The seasonal water consumptive use of potato crop was higher with the drip irrigation regime of 80% ET0 (1708.55 and 1654.2 m3/ha) as compared to 60% ET0 (1281.41 and 1240.7m3/ha) in the 1st and 2nd seasons, respectively.
The total water applied to potato crop was higher with the drip irrigation regime of 80% ET₀ (3417.11 and 3308.42 m3/ha) as compared to 60% ET₀ (2562.83 and 2481.31 m³/ha) in the 1^st and 2^nd seasons, respectively.
The crop water use efficiency (C.W.U.E.) was significantly higher with the drip irrigation regime of 60% ET₀ (18.42 and17.49 kg/m³) as compared to 80% ET₀ (15.22 and14.47 kg/m³) in the 1^st and 2^nd seasons, respectively.
The field water use efficiency (F.W.U.E.) was significantly higher with the drip irrigation regime of 60% ET₀ (36.83 and 34.98 kg/m³) as compared to 80% ET₀ (30.44 and 29.14 kg/m³) in the 1^st and 2^nd seasons, respectively.
 Using plastic mulching resulted in the highest (C.W.U.E.) which the values were (17.98 and 17.20 kg/m³) in the 1^st and 2^nd seasons, respectively and (F.W.U.E.) values (35.92 and 34.41 kg/m³) in the 1^st and 2^nd seasons, respectively.
Therefore to maximize tuber yield (52.0 t/ha), drip irrigation should be scheduled at 80% ET₀ under the conditions of limited water availability. In order to optimize irrigation water, drip irrigation should be scheduled at 60% ET₀. This gives a tuber yield of 47.2 t/ha and saves 40% of irrigation water under conditions of limited water availability.
It is economically beneficial to use organic mulch. Apply organic manure at rate of 12.5t/ha along with the recommended dose of fertilizers. Incorporate organic mulch and potato plants after harvest to enrich soil fertility and sustains potato production for long time in sandy loam soil.