EFFECT OF FARMYARD MANURE APPLICATION ON PRODUCTIVITY OF POTATO (Solanum tuberosum L.) VAR. SPUNTA UNDER DRIP IRRIGATION REGIME IN NORTH NILE DELTA, EGYPT

Two field experiments were conducted to study the effect of drip irrigation regime and farmyard manure application 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 in two seasons of 2008/2009 and 2009/2010. Four treatment combinations involving two drip irrigation regimes (I₁: 60% ET_o and I₂: 80% ET_o) in main plots and two farmyard manure levels M₁: 5 ton.fed^-1and M₂: 10ton.fed^-1 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 (19.77 and 21.47 ton. fed^-1) as compared to 60% ET₀ (16.42 and 18.11 ton.fed^-1) in the 1^st and 2^nd seasons (2008/2009 and 2009/2010), respectively.
Application of higher level of farmyard manure i.e. 10 ton. fed^-1  resulted in a significantly higher yield of tubers in the two Seasons (20.98 and 22.68 ton. fed^-1) as compared with the lower level of organic manure i.e.5 ton. fed^-1 (17.62 and 19.32 ton. fed^-1) in the 1^st and 2^ndseasons, respectively
This increase in potato yield may be attributed to a significant improvement in the growth and yield components.
    On an average of the two seasons, water use efficiency obtained was a significantly higher with the drip irrigation regime of 60% ET₀(33.71 kg.m^-3) as compared with 80% ET₀(30.19 kg.m^-3), Whereas, the total water requirement of potato crop was higher with the drip irrigation regime of 80% ET₀ (683.34 kg.m^-3) as compared to 60% ET₀(512.41 kg.m^-3). Therefore To maximize tuber yield recorded with average 20.62 ton. fed^-1, drip irrigation should be applied at 80% ET₀ under the conditions of the limited water supply in Egypt. Application of drip irrigation at 60% ET₀ gives average of a tuber yield 17.27 ton. fed^-1and saves 33% of irrigation fresh water which is a limited resource in Egypt.
Over the two seasons, the average protein yield increase was 60 % higher with the drip irrigation regime of 80% ET₀ as compared to 60% ET₀. Also, the average of nutrient uptake (N, P and K) was significantly higher with the drip irrigation regime of 80% ET₀ as compared to 60% ET₀and increasing with the application of higher level of farmyard manure. Since the soils are sandy and poor in organic matter content, it is advisable to apply farmyard manure at 10ton.fed^-1along with the recommended dose of fertilizers which gives average of a tuber yield 21.83 ton. fed^-1.