关键词: 褐土, 耕地质量, 物理指标, 化学指标, 作物产量

Abstract:

【Objective】The quality of cultivated land is a key factor affecting soil productivity, which serves also as scientific basis for rational fertilization. Cinnamon soil is the main soil type at the production area of wheat and corn in China. This study examined the current status of cultivated land quality and the evolution characteristics of cinnamon soil during the past 31 years (1988-2018). Though considering the evolution of fertilizer application rate, their influence on productivity was studied, and the guidance for reducing fertilizer input and increasing efficiency in cinnamon soil area was proposed.【Method】Using the data of 103 long-term (31 years) location test points in China, the evolution of cinnamon soil cultivated land quality was analyzed by combining physical and chemical indexes. The factors influencing the yield were compared through the redundancy analysis (RDA). Based on these results, reasonable suggestions were put forward to reduce fertilizer input and increase efficiency in cinnamon soil area.【Result】(1) The present situation and evolution of soil physical and chemical properties in cinnamon soil area were shown in the study. Specifically, the average values of organic matter content, available phosphorus and available potassium in 2018 were 17.9 g·kg ^-1, 29.2 mg·kg ^-1-and 164 mg·kg ^-1, respectively, which represented an increase of 21.2%, 200.9% and 52.0% during 31years, respectively. The average values of total nitrogen and slow available potassium in 2018 were 1.1 g·kg ^-1 and 945 mg·kg ^-1, respectively, which remained relatively stable during the monitoring period. The contents of soil secondary elements and micronutrient elements and heavy metals were in an acceptable range. The pH was reduced by 0.3 unit. Topsoil thickness was 21.9 cm and bulk density was 1.33 g·cm ^-3, which belonged to the middle level. (2) The fertilizer application rate in cinnamon soil area was 730.2 kg·hm ^-2 in 2018. The proportion of N (N):P (P₂O₅):K (K₂O) was about 2:1:1, and the proportion of chemical fertilizer to organic fertilizer was about 3.45:1. The nitrogen fertilizer application rate was 378.9 kg·hm ^-2, which was stable during the past 31 years. The application rate of phosphate and potassium fertilizer decreased by 24.1% and 50.8%, respectively. (3) The wheat yield showed an upward trend during 31 years, and the maximum reached 6 651 kg·hm ^-2 at the end of monitoring, which was 27.6% higher than the value at the initial stage. The corn yield was stable, reaching 8 851 kg·hm ^-2 at the end of monitoring. The contribution rate of soil fertility in wheat season and corn season was 49.0% and 59.6%, respectively. The yield was influenced by soil physical factors, including the thickness of plough layer (which could explain the wheat production for 2.7%, denoted as explanation rate), bulk density (explanation rates of wheat and corn productions for 1.2% and 1.5%, respectively) and chemical index, such as organic matter explanation rates of wheat and corn productions for 2% and 1.7%, respectively, and available phosphorus (explanation rate of corn for 3.6%). The explanation rates of potassium fertilizer were the highest for wheat and corn productions, which reached 5.6% and 6%, respectively. The explanation rates of phosphorus fertilizer for wheat yield (1.3%) and of nitrogen fertilizer for corn yield (1.3%) were also relatively high.【Conclusion】The cultivated land quality in cinnamon soil area has been improved in 31 years, but the overall fertility was low and the physical properties were in middle level. Considering the impact of land quality on productivity, different fertilization schemes needed to be formulated for wheat and corn. Both of which needed to increase the input of potassium fertilizers, and focused on ensuring the supply of phosphorus fertilizers for wheat and nitrogen fertilizers for corn. Physical indicators needed to be highly concerned. The topsoil thickness and bulk density were at a medium level, but there was no need to continue to optimize, and maintaining the status quo was more conductive to obtaining high yield.

Key words: cinnamon soil, cultivated land quality, soil physical properties, soil chemical properties, crop yield