CN1920557A - Black earth fertility evaluation index system - Google Patents

Abstract

The present invention intends to use classical statistical methods to study the fertility evaluation index and evaluation method of the black soil area in Heilongjiang Province, carry out key research and screening on the related indexes of black soil fertility, and determine the evaluation index and evaluation method of farmland black soil. By using the SAS software program data to analyze the collected black soil sample points, and then according to the principal component analysis data, the F value of the black soil fertility characteristic value is obtained. According to the size of the F value, we divide it into 5 grades. The fertility traits of the black soil area can be scientifically evaluated from the fertility differences of the five levels.

Description

Evaluation Index System of Black Soil Fertility

technical field

The invention belongs to the technical field of agricultural production and relates to a black soil fertility evaluation index system.

technical background

Northeast black soil is one of the three major black soils in the world. It is mainly distributed in Heilongjiang and Jilin provinces, covering an area of about 10 million hectares. It is the main commercial grain and animal product base in my country. In the total area of cultivated land in Heilongjiang Province, black soil accounts for about 43%, which is relatively fertile soil. This is just a qualitative statement, lacking the support of scientific evaluation indicators. Due to the various ways of using soil resources, it is quite difficult to use a specific index to evaluate soil fertility. Larson and Pierce (1991) proposed indicators for controlling soil erosion or preventing surface water and groundwater pollution: soil texture, structure and strength, plant available water and maximum rooting depth are plant indicators; available nutrients, total carbon, unstable Organic carbon, pH and electrolytic conductivity are chemical indicators.

Zhao Qiguo et al. (1997) pointed out in the study of soil quality and sustainable environment that for a long time, most scientists believed that human activities mainly caused the quality degradation of air and water resources, and few people realized that soil quality would also change under different utilization and management conditions. Severe degradation occurs. Only in recent years has there been increasing attention to the role of soil quality in sustainable production and its relationship to plant and human health. Especially in specific production practices, people began to realize that soil quality is the most sensitive method to indicate dynamic changes in soil conditions, which can reflect both changes in soil management and the ability of soil to restore degradation. It was based on this understanding that the United States held two consecutive academic seminars on soil quality in 1991 and 1992, and published a series of articles.

Sun Bo et al. pointed out in the article "Comprehensive Evaluation of Soil Fertility in Southeastern Hilly Areas of my country" that there are many evaluation methods for soil fertility resources, and the selected evaluation indicators are not consistent. Most of the previous evaluation methods considered dividing the quantitative level of soil fertility evaluation indicators and the weight coefficients of each index, and then using simple addition and multiplication to synthesize a comprehensive index to evaluate the level of soil fertility. The general evaluation index is divided into three levels, the first level is the comprehensive index of soil fertility; the second level contains two independent items, one indicates the status of soil nutrients, and the other indicates the status of soil supplying plant nutrients. Physical and chemical environmental conditions; the third layer is a single fertility index that intersects with each other.

The invention only proposes some evaluation indexes for the black soil in Northeast China, which has important guiding significance for the agricultural production in the black soil area.

Contents of the invention

The present invention mainly collects, tests and analyzes 660 sample points of 0-20cm in the black soil area of Heilongjiang Province, applies the method of classical statistical principal component analysis to analyze 8 nutrient indexes of farmland black soil, and evaluates the fertility traits of the black soil area at the same time . The principal components are selected according to the cumulative contribution rate, and the first five principal components can be selected. The amount of information contained in the first five principal components accounts for 93.09% of the total amount of information.

From the perspective of standard deviation, the first principal component (Z ₁ ) is approximately equivalent to the information reflected by 2.5 original indicators. The contribution rate of the first principal component is 48.43%, that is to say, the five indexes of total phosphorus, alkaline nitrogen, total nitrogen, total carbon and carbon-nitrogen ratio play an important role in the evaluation of fertility indexes. The above five indicators can reflect half of all nutrients in the first principal component; the second principal component (Z ₂ ) is approximately equivalent to the information reflected by 0.48 original indicators. The contribution rate of the second principal component is 16.89%, which can reflect 16.89% of the total amount of information; the third principal component (Z ₂ ) is approximately equivalent to the information reflected by 0.14 original indicators. The contribution rate of the third principal component is 10.83%, which can reflect 10.83% of the total amount of information; the fourth principal component (Z ₂ ) is approximately equivalent to the information reflected by 0.10 original indicators. The contribution rate of the fourth principal component is 9.08%, which can reflect 9.08% of the total information; the fifth principal component (Z ₂ ) is approximately equivalent to the information reflected by 0.29 original indicators. The contribution rate of the fifth principal component is 7.86%, which can reflect 7.86% of the total information.

Table 1 The common factor variance of each fertility index and the eigenvalues and contribution rates of its principal components Fertility indicators first principal component second principal component third principal component fourth principal component fifth principal component Total Phosphorus Total Potassium Alkaline Hydrolysis Nitrogen Available Potassium Available Phosphorus Total Nitrogen Total Carbon Carbon Nitrogen Ratio Eigenvalue Cumulative Contribution Rate/% Standard Deviation 0.4266-0.17880.41250.17650.03750.46340.48930.35953.874148.432.5229 0.27440.5222-0.03910.32400.7170-0.0014-0.0645-0.16531.351365.320.4846 0.22810.3305-0.0146-0.89590.10130.09720.10890.06630.866776.150.1399 -0.03240.7448-0.03000.2325-0.58640.04950.11170.17440.726885.240.0983 0.0340-0.0598-0.44200.03930.1761-0.34070.02330.80670.628493.090.2876

With the 660 sample point soil samples of measured black soil area 0-20cm, utilize SAS software program, data is carried out principal component analysis (seeing table 1), then according to principal component analysis data, obtain black soil fertility representative value F value, According to Table 1, we can get:

Y _Z1 ＝X ₁ ×0.4266+X ₂ ×(-0.1788)+…+X ₈ ×0.3595

Y _Z2 ＝X ₁ ×0.2744+X ₂ ×0.5222+…+X ₈ ×(-0.1653)

... ...

... ...

Y _Z5 ＝X ₁ ×0.0340+X ₂ ×(-0.0598)+…+X ₈ ×0.8067

From the above equation and the contribution rate value in Table 1, the F value can be obtained, see Table 2:

F=Y _Z1 ×48.43% (Z ₁ contribution rate)+Y _Z2 ×16.89% (Z ₂ contribution rate)+…+Y _Z5 ×7.85% (Z ₅ contribution rate)

The F value can be used to comprehensively evaluate the black soil fertility, which has certain guiding significance for the classification of black soil fertility.

Table 2 Fertility classification of black soil Number of samples F value range Geographical grade Geographical situation Proportion of samples (%) 8319116114379 >10-1-0.5-0-1--0.5<-1 12345 Most Fertile Fertile Medium Fertile Poor Fertility Least Fertile 12.6329.0724.5121.7712.02

According to the size of the F value, we divide it into 5 grades, among which the F value is > 1, which is defined as the fattest, with 83 samples, accounting for 12.63% of the total samples; the F value is between 0-1, There are 191 sampling points, accounting for 29.07% of the total sampling points; the F value is between -0.5-0, which is defined as medium fertility, and there are 161 sampling points, accounting for 24.51% of the total sampling points; If the value is between -1--0.5, it is defined as poor fertility, with 143 sampling points, accounting for 21.77% of the total sampling points; if the F value is <-1, it is defined as the worst fertility, with 79 sampling points, Accounting for 12.02% of the total samples.

Implementation

The invention was applied in the major knowledge innovation project (KZCX1-SW-19-3-01) of the Northeast Institute of Geography and Agricultural Ecology, Chinese Academy of Sciences from 2003 to 2005. Soil fertilization and scientific fertilization have important guiding significance, and have very important theoretical and practical significance for the agricultural production of the entire black soil area; at the same time, the government departments have certain practical significance for the macro-control and decision-making of the fertility characteristics of farmland black soil.

Claims (1)

1. a fertility evaluation index system is characterized in that utilizing the SAS software program to analyze the soil sample data of measuring in the black soil region, obtains black soil fertility characterization value F (tentatively titled), estimates the index of black soil fertility: F＞1 with this, and is the most fertile; 0＞F＞1, better;-0.5＞F＞0, middle fertility;-0.5＞F＞-1, fertility is relatively poor; F＜-1, fertility is the poorest.