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Aims: Two field experiments have been carried out to study the effect of different irrigation periods in the presence of compost as an organic amendment on the yield and quality of lupine (Lupinus termis L.) under the sandy soil conditions.
Study Design: Split-plot design.
Place and Duration of Study: The successive winter seasons of 2016/2017 and 2017/2018 at the Ismailia Agricultural Research Station, (30°35'30" N 32°14'50" E elevation 3 m), Agricultural Research Center (ARC), Egypt.
Methodology: Compost has been applied at the rates of 11.90, 23.81 and 35.71 ton/ha before planting. Three irrigation intervals were assigned after planting by 3, 6, and 9 days; the applied water volume for each was 4761.91 m3/ha.
Results: After harvesting, some parameters were estimated. As the compost rates increased, the soil EC significantly decreased while the available N, P, K, and Fe were significantly increased by 9.51, 12.79, 5.17, and 5.8%, respectively. For same compost rate, the irrigation intervals (3, 6, and 9 days) significantly decreased the available N relatively by 2.88, 5.16, and 6.96%, respectively and the available K by 3.45, 5.06, and 4.37%, respectively. The 6 days interval showed that most significant increase in the seeds' content of nutrients at different compost rates and the seed yield has increased by 19.59, 22.31, and 21.88% for the compost rates of 11.90, 23.81, and 35.71 ton/ha, respectively. The relative increase was by 20.48, 7.63, 4.49, 10.89, and 14.92% for the crude protein, crude lipids, total ash, TSS and the amino acids, respectively. The effect of treatments on the relative shoot moisture (%) and the field water use efficiency (F.W.U.E.) (kg/m3) was discussed.
Conclusion: The 6 days irrigation interval along with a compost application rate of 23.81 ton/ha can be recommended for lupine grown in sandy soil as they showed the most significant increase in the nutrients content of seeds by 22.31%.