(1) In the southern foothill of the Mt. Sanbe, Shimane-Ken, there is a speccial custom for barley cultivation without any fertilizers and letting water flow away constantly on all over the flatting drill. The aim of this irrigation method is to keep the yield of the barley culture by keeping the temperature high, and melt out the snow and using the fertile effect of water.
(2) In order to know the effect of irrigation at the various stage of growth upon barley culture, I have experiment the pot culture test, and the test in farm at the Sanbe.
(3) In the pot culture test, I supplied each pot, with 67 l of city water every day.
Though most water poured into a pot was overflowed out of it, the remaining of the poured water, about 7 l a pot, penetrated to the soil in the pot, and rans out through the bottom hole of it. At the test in the field, the amount of irrigation water reached roughly to 20,000 Koku per Tan every day.
(4) For the duration of the irrigation, the soil temperature of the control plot was influenced by the air temperature, and the soil temperature of the irrigation plot was influenced by the water temperature. In the sever cold season, as the water temperature is so higher than the air temperature, it was very remarkable for the effect to the temperature high.
(5) Records of the barley growth at various stages
a) The pot culture test : - At the earlier stage of growth, the barley lengthens its leaf in high degree by the irrigation method, but it became slow by and by after the heading sprouting period. There was no influence of this method at the later stage.
b) The test in the field : - The plant length and the weight of living body increase by the irrigation method, but it decrease only the number of stalk.
(6) The heading sprouting period is hastened more or less by the irrigation method.
(7) Result in harvesting
a) The pot culture test : - The length of ears' the weight of one ear, the grain numbers of one ear, and the grain weight of one ear increased by the irrigation of earlier stage, but the plant decreased the numbers of ears on a stub. At the irrigation in the later stage, it increased only the numbers of ears on a stub.
b) The test in the field : - The numbers of ears on a stub decreased, but the grain weight of one ear increase, as the result the yield of the treatment plot increased.
(8) The weight of thousand grains was not so, much whenever the irrigation was executed.