Effects Of Soil Acidification And CaCN₂ On Cucumber Growth And Development And Root-knot Nematode Disease

Soil continuous-cropping obstacle has become the key problem in greenhouse production recently. And much research were emphasized on soil secondary saltlization and soil nutrients unbalancement, but little on effects of soil acidification and its effects on crops growth and disease prevails. Root-knot nematode (Meloidogyne incognita) caused billions of dollars in annual crop losses in greenhouse. And there were little research on the effects of soil acidification to root-knot nematode disease. Used the cucumber variety of'Jinyouyihao', the experiments were carried out with pots in order to study the effects of soil acidification on cucumber growth and root-knot nematode disease, and the effects of CaCN₂ on soil circumstance, cucumber growth and development and root-knot nematode disease. And we also expected it could provide theoretical foundation and reference. Results were as follows:1. There were 4 pH value ranges by simulated soil acidification, respectively 6.8⁷.4,6.2⁶.8,5.6⁶.2,5.0⁵.6. The results showed that soil acidification decreased cucumber stem diameter, but increased plant height and leaf area. So soil acidification decreased quality of cucumber seedlings. With the soil acidification became serious, pH from 7.4 to 5.6, leaf chlorophyll content increased and decreased from 5.6 to 5.0. The photosynthesis was decreased and finally cucumber yield was reduced.2. Of the physical indexes, SOD activity of leaves and roots deceased with acidification decreasing. POD activity showed little changes. CAT activity of leaves and roots was increased with low acidification and decreased with high acidification. MDA content of leaves increased with soil acidification severe, and MDA content of roots was increased with low...