连茬栽培对人工营养土理化性质及番茄产量的影响

通过利用当地的玉米秸秆为主要材料与土壤、草炭分别按不同的比例配制的人工营养土与土壤做比较,通过物理化学的方法检测所配人工营养土的营养成分、物理化学特性的好坏,并在日光温室内对番茄进行试验,研究所配制的人工营养土对番茄的生长发育、产量和各种品质的影响。研究结果表明,人工营养土栽培可以在很大程度上改善番茄植株的产量。在本试验所做的四个处理中,处理B:土:玉米秸秆=1:2+鸡粪(15kgm-3)和处理D:草炭:玉米秸秆=1:2+鸡粪(15kgm-3)的处理效果较好,考虑到经济和节省资源等因素,建议在生产中应用处理B:土:玉米秸秆=1:2+鸡粪(15kgm-3)。     

晋西沿黄地区水土流失危害及防治对策研究

晋西沿黄地区是黄河中游水土流失最严重的地区之一。20世纪90年代末水土流失面积为20777.0km~2,占研究区土地总面积的79.30％,较70年代末水土流失面积17 912.54 km~2增加了2 864.46km~2,平均每年以143.23 km~2的速度在扩展。水土流失造成该区可利用土地面积减少、土地生产力下降、农田水利设施被破坏、生态失调等危害。为此,本文依据研究区水土流失的现状及危害,提出了以山西省可持续发展为目标的水土流失综合防治对策。     

Coarse particulate organic matter is the primary source of mineral N in the topsoil of three beech forests

Forest soils contain a variable amount of organic N roughly repartitioned among particles of different size, microbial biomass and associated with mineral compounds. All pools are alimented by annual litter fall as main input of organic N to the forest floor. Litter N is further subject to mineralization/stabilization recognized as the crucial process for the turnover of litter N. Although it is well documented that different soil types have different soil N stocks, it is presently unknown how different soil types affect the turnover of recent litter N. Here, we compared the potential mineralization of the total soil organic N with that of recent litter-released N in three beech forests varying in their soil properties. Highly ¹⁵N-labelled beech litter was applied to stands located at Aubure, Ebrach, Collelongo, which differ in humus type, soil type and soil chemistry. After 4-5 years of litter decomposition, the upper 3 cm of the organo-mineral A horizon was sampled and the net N mineralization was measured over 112 days under controlled conditions. The origin of mineralized N (litter N versus soil organic N) was calculated using ¹⁵N labeling. In addition, soils were fractionated according to their particle size (>2000 μm, 200-2000 μm, 50-200 μm, <50 μm) and particulate organic matter (POM) was separated from the mineral fraction in size classes, except the <50 μm fraction. Between 41 and 69% of soil organic N was recovered as POM. Litter-released ¹⁵N was mainly to be found in the coarse POM fractions >200 μm. On a soil mass basis, N mineralization was two-fold higher at Aubure and Collelongo than at Ebrach, but, on a soil N basis, N mineralization was the lowest at Collelongo and the highest at Ebrach. On a soil N (or ¹⁵N) basis, mineralization of litter ¹⁵N was two to four-fold higher than mineralization of the average soil N. Furthermore, the δ¹⁵N of the mineral N produced was closer to that of POM than to that of the mineral-bound fraction (<50 μm). Highest rates of ¹⁵N mineralization happened in the soil with the lowest N content, and we found a negative relationship between accumulations of N in the upper A horizon and the mineralization of ¹⁵N from the litter. Our results show that mineral N is preferentially mineralized from POM in the upper organo-mineral soil irrespective of the soil chemistry and that the turnover rate of litter N is faster in soils with a low N content.     

蔬菜大棚墒情预报的衰减指数平滑模型

利用宿迁市船行灌区实测数据率定衰减指数平滑模型的参数,研究了衰减指数平滑模型在蔬菜大棚墒情预报中的适用性。结果表明,与霍尔特双参数模型相比,衰减指数平滑模型改善了预报效果,用于蔬菜大棚墒情预报具有较高的精度。     

长期定位监测钾肥施用效果研究

缺钾是水稻土的主要障碍因子之一,合理增施钾肥,既能促进水稻的营养代谢,又能大幅度提高水稻产量。为此本文利用5 a施肥定位监测资料,研究了钾肥在水稻土上的施用效果。结果表明:施用有机肥增施钾肥一般可增产6%左右,不施有机肥增施钾肥一般可增产4.9%左右。增施农肥及氮、磷、钾肥配合使用,才能保证水稻高产稳产。