SummaryDifferent photoperiodic treatments within 2 types of light dark cycles ranging from 24 to 30 h were applied to Peking ducks. The first consisted of constant photoperiods (1, 8L: 16D; 2, 14 L: 10D; 3, 18L:6D; 4, 14L: 13D; 5, 14L: 16D and 6, continuous light) and the second of intermittent cycles (1, 6L:2D:2L:14p; 2, 6L:4D:2L:12D; 3, 6L:6D:2L:10D; 4, 6L:8D:2L:8D and 5, 14L:½D:3½L:6D). The traits studied varied in response according to the photoperiodic regimes used. Rate of lay and eggs laid in the modal 8 h period increased with the duration of the light period in the cycle. Sequence lengths of 1–3 eggs were most frequent under all photoperiodic regimes (constant and intermittent). Length of intra-sequence interval (h) showed an inverse relationship with length of inter-sequence interval. A pause length of 2–4 days was the most frequent for all the different light-dark cycles. Egg weight was heavier in the second season than in the first when the light period of the photoperiodic regime was long. Weights of albumin and yolk showed similar trends to egg weight. The latter differences were significant, while shell weight differences were not significant. Plasma progesterone lvels were lowest in non-laying ducks. The highest values in laying ducks were before ovulation. The highest level of cortisol was shown during the last hours of the dark period. Differences from ovulatory cycle to another were observed.
Calcareous soils generally have some problems; poor soil physical and chemical properties, crusting, salinity and low productivity. Optimizing water application by irrigation scheduling increases water use efficiency, growth and yield of crops in addition to water rationalization. The aim of the present work was to study the effect of irrigation scheduling, soil mulching and soil amendments application rates on some physical properties of a clay calcareous soil and soybean production and crop water relations. A field experiment was conducted at Menshat Rabie Village, Itsa District, Fyoum Governorate, Egypt. Three irrigation treatments were applied i.e., I 1 (1.0 of cumulative pan evaporation, C.P.E.), I 2 (0.8 of C.P.E.) and I 3 (0.6 of C.P.E.). Two soil mulching treatments were applied, i.e., without soil mulching and black plastic mulching. The effects of two soil amendments namely poultry manure and agriculture sulfur were also tested. Three levels of each soil amendment were applied: (17.86, 35.71, and 53.57 m 3 ha -1 of poultry manure) and (178.57, 357.14 and 535.71 kg ha -1 of agricultural sulfur). The experiment included 36 treatments distributed in a split split design with three replicates. Soybean (Glycine max. Giza 111 variety) was grown along two successive seasons (2014 and 2015). Obtained results showed that the applied treatments resulted in significant and considerable effects on the studied soil properties such as, decreases of soil bulk density and increases each of total porosity, available water content, soil hydraulic conductivity values and soybean plant growth and productivity. Applied treatments improved water consumptive use and increased the water use efficiency values of soybean crop. It was concluded the application of irrigation treatment 0.8 of cumulative pan evaporation with the use of poultry manure at the rate 53.57 m 3 ha -1 under mulching with black plastic were superior than all other studied treatments and could save about 20% of water requirements of soybean crop grown on a clay calcareous soil.
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