The Grow th Path of Agricultural Labor Productivity in Major Grain Producing Areas

Ning ZHOU，Qifeng CUI

1.School of Economics，Nanjing University of Finance and Economics，Nanjing210023，China；2.Institute of Agricultural Economics and Development，Chinese Academy of Agricultural Sciences，Beijing 100081，China

The agricultural labor productivity is an important indicator for measuring the agricultural development of one region，and its growth is ascribed to the increase in production factors or the improvement of efficiency.The major grain producing areas are the main force of China's grain supply，bearing the responsibility to ensure national food security.The growth path of agricultural labor productivity in major grain producing areas is of great importance to the domestic food production，and affects the food production stability and future development sustainability in major grain producing areas.Therefore，the study of the law and growth path of agricultural labor productivity in major grain producing areas，is of very important significance to China's agricultural modernization and food security in China.

The agricultural labor productivity has long been studied abroad，and especially Yujiro Hayami et al.［1］have gained significant achievements in terms of agricultural labor productivity.They use the data concerning high，middle and low-income countries during the period 1960－1980 for the international comparison of agricultural labor productivity，and divide the agricultural growth path in various countries into the growth path of land productivity and the growth path of labor equipment ratio.

The Chinese scholars draw inconsistent conclusions on whether the agricultural output growth in China is mainly from the increase in factor inputs or productivity improvement.Wang Xiaoping［2］draws the conclusion that the growth path of China's agricultural labor productivity over 50 years（1952－2003）is＂increase in labor inputs-improvement of land productivity-improvement of agricultural labor productivity＂.

The analysis of Guo Qingwang et al.［3］show that the economic growth differences between the Chinese provinces were great from 1979 to 2003，and there is a tendency to gradually expand，which is mainly caused by the gradual expansion of differences in technical process rate.Luo Liangguo et al.［4］analyze the factors influencing the agricultural growth of China's major grain producing areas in different periods，and draw the conclusion that the adjustment and optimization of agricultural structure and the full exertion of regional advantages are the important factors for promoting the agricultural development in major grain producing areas.

Most scholars still form a relatively consistent view［5－7］.Currently，in terms of the relative amount of the Chinese agricultural production factors and agricultural labor productivity，the output mode of increasing production factor inputs to bring economic growth occupies the main position of economic growth.However，from the effects of the overall macroeconomic growth，it still ultimately depends on the improvement of agricultural labor productivity.

Starting from the question＂Does the growth of agricultural labor productivity in China's major grain producing areas mainly come from the increase in factor inputs or the improvement of production efficiency？＂，we learn from the research methods of Yujiro Hayami et al.to derive the growth path of agricultural labor productivity in major grain producing areas，and put forth practical policy recommendations for the sustainable agricultural development in major grain producing areas and national food security from the labor productivity.

1 Data and model setting

We learn from the method of comparing the international agricul-tural productivity by Yujiro Hayami et al.［8］，to analyze the growth path of agricultural labor productivity（Y／L）inmajor grain producing areas.The productivity per unit of land（Y／A）and the growing area of crops per unit of labor（A／L）represent the efficiency of agricultural output and production factor inputs，respectively.The agricultural labor productivity（Y／L）can be decomposed into the product of productivity per unit of land（Y／A）and the growing area of crops per unit of labor（A／L），as shown in formula（1）.

Take the logarithm on both sides of formula（1）：

The data in this study are from Fifty yearsof New China Statistical Data Collection（1949－2004），China Agriculture Yearbook（1979－2010）and the related data concerning 13 major grain producing areas（Liaoning，Jilin，Heilongjiang，Inner Mongolia，Hebei，Henan，Hubei，Hunan，Shandong，Jiangsu，Anhui，Jiangxi and Sichuan）.

2 Empirical analysis of the grow th path of agricultural labor productivity in major grain producing areas

The growth pathmap of agricultural labor productivity in 13 major grain producing areas from 1979 to 2010 is shown in Fig.1.

Both the starting point and end point of data take the three year average can effectively avoid data anomalies in a given year，and taking logarithm of the independent and dependent variables can ignore the measurement unit of variables，making the results have the meaning of elasticity.

Fig.1 The agricultural grow th path of 13 major grain producing areas

Each arrow in Fig.1 represents the growth path of agricultural productivity in one major producing area，and from the gradient and length of growth path map，we can get the differences in the growth path of agricultural labor productivity between the major grain producing areas.

2.1 Simultaneous increase in the agricultural labor productivity and land productivity in major grain producing areas

The growth rate of the agricultural labor productivity（Y／A）and land productivity（Y／L）in major grain producing areas over 30 years is shown in Table 1，namely the ratio of horizontal and vertical coordinates in the early period to horizontal and vertical coordinates in the late period in Fig.1.

From the numerical value，the growth rate of Y／L is about3，and it is the highest in Inner Mongolia（3.7），while the lowest in Heilongjiang（1.9）；the growth rate of Y／A is mostly greater than 1，and it is the highest in Anhui（13）.Overall，during the period 1979－2010，the agricultural labor productivity and land productivity were increased simultaneously in 13 major grain producing areas，making the total value of agricultural production increase significantly.

The above analysis shows that in terms of resources and efficiency，the growth of agricultural labor productivity in China's major grain producing areas mainly relies on the increase in the production factor inputs per unit of labor and the growth of agricultur-al labor productivity still falls within the resource type.

This is basically consistent with the conclusion drawn by Clark［9］that when the new technology can not be effectively adopted，the gap in labor productivity does not come from technological differences，nor does it come from the differences in education or workers' physical fitness.

Major grain producing areas are rich in agricultural land resources，but in comparison with the western countries with developed agriculture or even Japan，China is not a country with abundant agricultural land resources，and the reasons for the rapid growth of agricultural labor productivity mainly relying on the increase in resource endowments need to be explored.

2.3 The reduction of agricultural labor as the main reason for the increase in the production factor inputs per unit of labor in major producing areasAccording to the dual economic theory of Lewis［10］，the economy of developing countries consists of traditional sectors and modern sectors，and the wage gap between the traditional sectors and the modern sectors results in the labor flow.The modern sectors continuously expand，and for the traditional sectors，the labor productivity is promoted after the surplus labor is absorbed.

Based on this point，we continue to carry out in-depth analysis of the reasons for the increase in the production factors per unit of labor in major grain producing areas from the perspective of agricultural labor transfer in the traditional sectors.

Statistics show that the total sown area of crops in China showed an increasing trend from 1979 to 2010（148.4769 million hm2in 1979 and 160.675 million hm2in 2010），and the total sown area of grain crops also rose.The reason is that the national farmland protection policies become increasingly stringent，the area of arable land for crops is reduced slowly，and with the continuous improvement of multiple cropping index，the total sown area of crops does not fall but rise.

The agricultural labor concentration index is used to analyze the changes in agricultural labor in 13major producing areas，and the results are shown in Table 2.It can be found that since 1986，only the agricultural labor concentration index in Anhui Province has kept above1，and the agricultural labor concentration index in other provinces has the values fluctuating below 1.

The high agricultural labor concentration index indicates that there are many agricultural labor forces in Anhui Province，and compared with the amount of labor in other industries，the agricultural labor has not been significantly reduced over 30 years.

And it can be verified that the impact of changes in the number of labor in various regions on total value of agricultural production is elastic，and the impact of reduction of labor on agricultural output plays an amplifying role.In major grain producing areas except Anhui Province，under the precondition of limited potential of agricultural production factor input，the improvement of labor productivity mainly comes from the reduction of the number of agricultural labor，rather than the increase in the absolute value of production factors per unit of labor.

Since the reform and opening up，the reduction of absolute number of agricultural labor in major grain producing are as has increased the production factor input per unit of labor，and this growth pattern is clearly not the sustainable growth pattern.

Table 2 The agricultural labor concentration index in major grain producing areas

2.4 The efficiency improvement as the future grow th focus of agricultural labor productivityThe growth of agricultural labor productivity of Anhui Province shows the path inconsistent with that of other provinces，and this efficiency-type growth path relying on the productivity per unit of land is in line with the development path of greatly enhancing the agricultural production efficiency with limited agricultural production factors.

However，after comparing the number of agricultural labor per unit area of Anhui Province and the data concerning Jiangsu Province with similar conditions for agricultural production，it is found that in 1980 and 2010，the agricultural labor input quantity per unit area in Anhui Province was2.103 persons／hm2and 2.124 persons／hm2，respectively；the agricultural labor input quantity per unit area in Jiangsu Province was 2.409 persons／hm2and 2.186 persons／hm2，respectively.

We can see that the relative amount of agricultural labor in Jiangsu Province is reduced，while the amount of labor in Anhui Province is not reduced but increased.This growth path of Anhui Province shows a relatively backward stage of economic development，and its economy has not yet reached the development stage at which the agricultural labor is transferred to the secondary and tertiary industries，so that the agricultural output value per unit area is higher than the output value per unit of labor.

In order to verify this conclusion，with the data on Jiangsu Province and Anhuias samples，the actual agricultural output value as the dependent variable and time t as the independent variable，SPSSs oft ware is used to carry out time-series data regression，and the results show that the quadratic and cubic curves have good fitting effect on the two provinces，and the degree of explanation is greater than 0.9，but in terms of the coefficient index，the time coefficient of Jiangsu Province is greater than that of Anhui Province，indicating that the level of development is higher in Jiangsu Province，and in the subsequent development process，Anhui Province is bound to undergo significant reduction of agricultural labor and limited improvement of output value per unit of sown area.

Therefore，under the precondition of stable number of the Chinese agricultural labor in the future，the growth of agricultural labor productivity is impossible to depend on the increase in the production factor input，and the improvement of productivity per unit of production factor is still the path of future development.

3 Conclusions

This study avoids the complicated empirical models and a lot of tedious mathematical analyses.Using the simple and convenient method of empirical analysis，we carry out a progressive analysis of the growth of agricultural labor productivity in China's major grain producing areas，and it is found that since the reform and opening up，from the relative endowments of land and labor in China's major grain producing areas，the growth rate of the productivity per unit of land（Y／A）is higher than that of the output value per unit of labor（Y／L）.

In essence，this growth path of increasing the output value relying on increasing the production factor inputs is the reduction of labor，and the reduction of agricultural labor has a great elasticity of impact on the total value of agricultural production.

The transfer of agricultural labor to non-agricultural industries is the inevitable trend of historical development experience.In the course of non-agricultural transformation of labor in various developing countries，the agricultural labor productivity may be substantially increased，but this method of depending on the quantity of resources occupied to increase productivity is after all not the road of sustainable development.

In the context of completion of non-agricultural transfer of labor in China's major grain producing areas and stable number of agricultural labor，the growth of agricultural labor productivity in major grain producing areas still needs to rely on the improvement of efficiency，emphasize the research，development，promotion and application of agricultural science and technology to promote the productivity per unit of land，which is a sustainable growth path for the improvement of agricultural labor productivity.

Meanwhile，the food industry should undergo the industrial structure adjustment and follow the international trend.Vigorously developing agricultural science and technology to promote agricultural modernization is a good way to promote the agricultural labor productivity in China's major grain producing areas.

4 Discussions

As for the study of agricultural labor productivity，the predecessors have used different methods to explain from different angles.Jiang Naihua［11］links the agricultural labor productivity with the changes in the income of rural households，and believes that the decline in agricultural productivity is the direct cause of the decline in agricultural production operating income.

Xin Xiangfei et al.［12］，Bai Xuejie et al.［13］also believe that the gap in China's agricultural labor productivity level leads to the expansion of regional disparities.Through the analysis of the regional difference in factor endowments and agricultural labor productivity，Xin Xiangfei et al.［14］，Jiang Jiyu et al.［15］draw the conclusion that the difference in factor endowments is still an important factor affecting the agricultural labor productivity of different regions of China，and the difference in factor endowments contributes to the difference in the agricultural labor productivity between eastern and western areas，which is similar to the conclusions in this paper.

Wang Xiaoping et al.use regression analysis to explore the stages and characteristics of the Chinese agricultural labor productivity growth in the period 1952－2003，and reveals that the path of improving the Chinese agricultural labor productivity is the path of increasing labor input to promote land productivity and enhance agricultural labor productivity，which is consistent with the research ideas and conclusions in this paper.

Guo Qingwang［3］and Li Jingwen［16］estimate the total factor productivity and its contribution to economic growth in China from 1979 to 2004，and draw the conclusion that the growth rate of China's total factor productivity is low and the increase in factor inputs can not be ignored，which is exactly the same as our conclusion that at present，China's economic growth will still depend on the growth of factor inputs，but it is also necessary to pay attention to the role of factor productivity improvement in enhancing the long-term sustainable economic growth of China.

It can be found that the same view held by us and scholars is that currently，in terms of the relative amount of the Chinese agricultural resource endowments and production factor efficiency，the output mode of resource endowments bringing economic growth occupies a major position，but from the effects of overall macroeconomic growth，it will ultimately depend on the improvement of production factor efficiency.

Our study avoids the complicated empirical models and a lot of tedious mathematical analyses.Using the simple and convenient method of empirical analysis，we carry out a progressive analysis of the growth of agricultural labor productivity in China's major grain producing areas，and draw the conclusions highly consistent with previous conclusions.

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