Assessment And Improvement Of Cultivated Land Fertility In Liaoning Province

Cultivated land fertility is the integrated embodiment of soil productivity, whose increasing is the necessary way and strategy to ensure the grain safety in China. Liaoning Province is one of the important grain production provinces in China. Evaluating and improving provincially cultivated land fertility will be of great importance in grain production safety and agricultural sustainable development for this province. For this, based on the basic data of cultivated land fertility evaluation of counties in Liaoning Province, this study constructed an evaluation system of provincially cultivated land fertility. And then, the grade of cultivated land fertility was divided by using the Analytic Hierarchy Process method and Delphi method. Subsequently, the main obstacle factors between the grades of cultivated land fertility in Liaoning Province and its five areas were selected by statistical method in terms of provincial evaluation of cultivated land fertility, and then analyzing the difficulty degree of cultivated land fertility grade improvement, and finally proposing the improvement measures aimed at the above analysis. The results were as the follows:1. Establishing the index system of evaluation of cultivated land fertility in Liaoning Province, including 12 indices in 4 classifications by natural condition, the properties of soil profile, soil chemical and physical properties and soil management. And then, the grade of cultivated land fertility was divided by using the Analytic Hierarchy Process method and Delphi method.2. The grade of cultivated land fertility of Liaoning Province was divided into five grades. The area of the third grade was dominated in all grades, accounting for 33.90% of the total area; and the following was the grades of the forth and the second, accounting for 24.40% and 22.44%,respectively; the area of the first and the fifth grades had the minimum distribution, accounting for 9.96%and 9.30%,respectively.3. Making clear the main obstacle factors of improvement of cultivated land fertility in Liaoning Province, including organic matter, available phosphorus and irrigation capacity. Of which, organic matter and available phosphorus were easier to improve from the second grade to the second and from the third to the second than between other two adjacent grades. While irrigation capacity was difficult to improve between any two adjacent grades.4. There were differences in the improvement of main obstacle factors between any two adjacent cultivated land grades in all study regions.(1) The main obstacle factors in east Liaoning Province were effective soil depth, irrigation capacity and pH. Of which, the effective soil depth was relatively easier to be promoted from the second to the first grade, and from the third to the second grade, meanwhile, pH was improved at the grade of easy and medium during it in all regions promoted to the neutral range; (2) The main obstacle factors in west Liaoning Province were organic matter, irrigation capacity and available phosphorus. Of which, organic matter was only easier to be promoted from the second to the first grade; while, irrigation capacity was not easy to improve in all the grades; additionally, available phosphorus was easier to improve from the second to the first and from the third to the second grade; (3) The main obstacle factors in south Liaoning Province were organic matter, effective soil depth and pH. Of which, organic matter and effective soil depth were difficult to be promoted in all the grades, while the promotion of pH to the neutral range was easier from the second and the forth grades to the neutral than from the third and the fifth grades; (4) The main obstacle factors in north Liaoning Province were organic matter, available phosphorus and irrigation capacity. Of which, organic matter was relatively easy to be promoted from the second grade to the first, and from the third grade to the second; while, irrigation capacity was only easy to improve from the second grade to the first; additionally, available phosphorus was easy to be improved in any two adjacent grades except from the fifth grade to the fourth; (5) The main obstacle factors in central Liaoning Province were organic matter, available phosphorus and drainage capacity. Meanwhile, organic matter was relatively easy to be promoted from the second grade to the first and from the third grade to the second; and available phosphorus was easy to improve from the second grade to the first; while, drainage capacity was increased in any two adjacent grades except from the fifth grade to the fourth.5. Proposing the measures to the improvement of cultivated land fertility for the main obstacle factors, namely, increasing organic matter content by the application of organic combined inorganic fertilizers, and the straw returning; enhancing available phosphorus and other nutrients contents by reasonable application of fertilizers; regulating soil pH by using the lime and plaster; strengthening the construction of irrigation and drainage engineering to enhance the capacity of irrigation and drainage; and deepening the thickness of cultivated soil layer according to different local conditions. These measures will improve soil management conditions, which will help to promote the cultivated land fertility in Liaoning Province.