论文部分内容阅读
1.拟定了测定稻田土壤沉降系数的方法。取相当于风干土100克的原状土,加水搅匀后,置1,000毫升量筒中,加水至刻度,用搅拌棒以每分钟上下40次的速度搅拌1分钟,静置。观测开始出现浑水与土粒分界时,下层土壤容积的毫升数(A),及静置24小时下层土壤容积的毫升数(B),二者的比值称为沉降系数(C),以此作为结构状况的标志。其计算式如下:C=B/A。2.沉降系数与土壤有机质的质量有密切关系,土壤中的胡敏酸,其分子较复杂,土壤的沉降系数也较大。机械组成似对沉降系数值影响不大。3.沉降系数值(C)在1以下时,数值的大小与土壤耕性的好坏趋势一致,数值大,表示土壤耕性好;C 值在1以上时,表明土壤的起浆性强。4.水旱轮作利用方式下的水稻土,其沉降系数值恒较双季稻连作利用方式下者大,前者中的还原性物质量较少,NH_4~+-N 及速效磷量较多。冬浸田与冬种田比较,前者的沉降系数值较后者为小,还原性物质较多,速效性养分含量较低。
1. The method of determining the sedimentation coefficient of paddy soil has been drawn up. Take the equivalent of 100 grams of dried earth soil undisturbed soil, add water and stir well, set 1,000 ml graduated cylinder, add water to the mark, with a stirring rod 40 times per minute up and down the speed of stirring for 1 minute and let stand. (A) of the lower soil volume and the milliliters of the lower soil volume (B) standing for 24 hours, the ratio of the two is called the sedimentation coefficient (C) As a symbol of the status of the structure. The calculation is as follows: C = B / A. 2. Sedimentation coefficient and the quality of soil organic matter are closely related to soil humic acid, the molecular complexity, soil sedimentation coefficient is also larger. Mechanical composition seems to have little effect on the settlement factor. 3. When the sedimentation coefficient (C) is less than 1, the value of the numerical value is consistent with the trend of soil tillage, and the value is large, which indicates that soil tillage is good; when C value is above 1, it indicates that soil slurry has strong pulp. The paddy soil under the pattern of runoff and rotation of paddy soil had a higher sedimentation coefficient value than the continuous cropping pattern of double cropping rice. The amount of reducing substance in the former was less, and NH_4 ~ + -N and available phosphorus were more. Compared with the winter farming, winter submerged fields had lower sedimentation coefficient than the latter, more reducing substances and lower available nutrients.