| 1 | Characteristics of Nutrient Salt Uptake Associated with Water Use of Corn as a Catch Crop at Different Plant Densities in a Greenhouse显示文摘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-2, 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. | D.YASUTAKE C.KIYOKAWA K.KONDO R.NOMIYAMA M.KITANO M.MORI S.YAMANE M.MAEDA H.NAGARE T.FUJIWARA | 2014 | Pedosphere2014，24，3： | 2 |
| 2 | 新型除草剂——dithiopyr显示文摘ditbiopyr系美国孟山都公司开发的芽前除草剂,它具有很高的单位活性,以低剂量即可防除杂草。1985年以来,日本已将其作为水稻和草皮除草剂进行开发。本文根据1985~88年田间试验结果,扼要介绍该药剂的除草活性以及在水稻和草皮中的选择性。 dithiopyr的化学名称为:S,S-二甲基-2-(二氟甲基)-4-(2-甲基丙基)-6-(三氟甲基)-3,5-吡啶硫代二羧酸酯,其结构式如下: | M.Fujiyama M.KasaiM.Itoh S.Yamane 石蓉 | 1991 | 农药译丛1991，13，2： | 0 |
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