内乡烟区土壤养分状况及其综合评价

Status and comprehensive evaluation of soil fertility in Neixiang tobacco-growing areas

为明确内乡烟区土壤肥力状况，对内乡烟区601个土壤样品的10项养分指标进行了分析，并通过因子分析和主成分分析对土壤的肥力状况进行了综合评价．结果表明，内乡烟区土壤肥力存在广泛的变异．采用等间距法将土壤肥力分为4类．其中，第1类土壤综合肥力高，其综合得分≥0．5，包括48个土壤样品；第Ⅱ类土壤综合肥力较高，其综合得分为0．0～0．5，包括212个土壤样品；第Ⅲ类土壤综合肥力中等，其综合得分为-0．5～0．0，包括312个土壤样品；第Ⅳ类土壤综合肥力较低，其综合得分为≤-O．5，包括29个土壤样品．内乡烟区土壤全氮水平较高，有机质含量中等偏低，有效磷含量中等，较适宜；缓效钾含量较高，但速效钾含量处于适宜值下限；建议该区控氮增钾调磷，增施C／N值高的有机肥促进土壤缓效钾向速效钾的转化，不同地块养分变幅较大，应做到分类制订施肥方案．

To malce clear the soil fertility status, 10 indexes of the soil nutrient contents of 601 soil samples from Neixiang tobacco-growing areas were analyzed. Based on methods of factor analysis and principal component analysis, the comprehensive evaluation of soil fertility was conducted. The results of comprehensive evaluation indicated that there existed significant variation for the soil fertility of Nei- xiang tobacco-growing areas. The soil fertility could be classified into four ranks by cluster analysis. Rank 1 was of the highest soil fertility with comprehensive scores ≥0.5, including 48 soil samples;Rank 2 was of higher soil fertility with comprehensive scores 0.0 ～ 0.5, including 212 soil samples ; Rank 3 was of the medium soil fertility with comprehensive scores - 0.5 ～ 0.0, including 312 soil samples ; Rank 4 was of low soil fertility with comprehensive scores ≤ - 0.5, including 29 soil samples. The contents of total N was high in general, and the contents of organic matter, available P were me- dium; The contents of slowly available K was adequate,but the contents of available K was obviously deficient;It was suggested that N be controlled,P be added,and K be adjusted;to promote the conver- sion of slowly available K to available K,organic fertilizer with higher C/N shoud be added to the soil; according to different plots with larger nutrient change, classification fertilization program was needed to develop.