Dent corn, as a catch crop used for salt removal, was cultivated at different densities, i.e., 7.3 （low density）, 59.7 （normal density）, and 119.5 plants m-2 （high density）, during a 50 d fallow period after cul...Dent corn, as a catch crop used for salt removal, was cultivated at different densities, i.e., 7.3 （low density）, 59.7 （normal density）, and 119.5 plants m-2 （high density）, during a 50 d fallow period after cultivation of a commercial crop in a greenhouse, to analyze the characteristics of nutrient salt （N, K, Mg, and Ca） uptake by roots and to study the effect of plant density on the characteristics associated with crop water use. Leaf area index for the high and normal density treatments reached extremely high values of 24.3 and 14.9, respectively. These values induced higher transpiration rates that were estimated using the Penman-Monteith model with the incorporation of specific parameters for crop and greenhouse conditions. The total N, K, Mg, and Ca contents in the crop canopy at harvest were 26.8, 13.0, 1.0, and 1.7 g m-S, respectively, under the high density treatment. The dynamics of salt uptake rates for high, normal, and low density treatments were evaluated by assessing weekly changes in salt content, and were subsequently compared against the transpiration rate. A positive linear relationship was obtained between these 2 parameters for all 3 density treatments and all tested salts. Hence, higher transpiration rates caused higher salt uptake rates through water absorption. On the other hand, salt uptake efficiency per unit water use by cultivation was lower in the low density treatment. Therefore, management procedures with dense planting that induce higher transpiration rates and lower evaporation rate are extremely important for the effective cultivation of corn catch crops.展开更多
基金Supported by the Core Research for Evolutional Science and Technology(CREST)of the Japan Science and Technology Agency(JST)the Grants-in-Aid for Scientific Research(Nos.22780231 and 25850173)from the Japan Society for the Promotion of ScienceThis paper was presented at the Conference‘Biohydrology 2013’,Landau,Germany
文摘Dent corn, as a catch crop used for salt removal, was cultivated at different densities, i.e., 7.3 （low density）, 59.7 （normal density）, and 119.5 plants m-2 （high density）, during a 50 d fallow period after cultivation of a commercial crop in a greenhouse, to analyze the characteristics of nutrient salt （N, K, Mg, and Ca） uptake by roots and to study the effect of plant density on the characteristics associated with crop water use. Leaf area index for the high and normal density treatments reached extremely high values of 24.3 and 14.9, respectively. These values induced higher transpiration rates that were estimated using the Penman-Monteith model with the incorporation of specific parameters for crop and greenhouse conditions. The total N, K, Mg, and Ca contents in the crop canopy at harvest were 26.8, 13.0, 1.0, and 1.7 g m-S, respectively, under the high density treatment. The dynamics of salt uptake rates for high, normal, and low density treatments were evaluated by assessing weekly changes in salt content, and were subsequently compared against the transpiration rate. A positive linear relationship was obtained between these 2 parameters for all 3 density treatments and all tested salts. Hence, higher transpiration rates caused higher salt uptake rates through water absorption. On the other hand, salt uptake efficiency per unit water use by cultivation was lower in the low density treatment. Therefore, management procedures with dense planting that induce higher transpiration rates and lower evaporation rate are extremely important for the effective cultivation of corn catch crops.
