华南热带土壤养分含量状态及肥力评价

华南热带亚热带地区,广泛分布着红壤、黄壤、赤红壤、砖红壤以及在这些土壤上发育的水稻土.这个地区年平均气温在17-25℃之间,≥10℃的年积温为5000—9500℃,其中赤红壤和砖红壤地区,年平均气温在21℃以上,≥10℃年积温达7100—9500℃之其中赤红壤和砖红壤地区,年平均气温在21℃以上,≥10℃年积温达7100-9500℃之间,年降雨量在1500毫米以上,是我国发展热带、亚热带经济作物和林果木的良好基地,也是发展以水稻为主的粮食作物的好地方^1,7-9].

FORMS AND CONTENT OF NUTRIENTS IN SOIL OF TROPICAL REGION IN SOUTH CHINA AND THE EVALUATION OF THEIR FERTILITY

This paper deals with the forms and content of N, P, K, Ca, Mg, available SiO₂ and micronutrients in soils of tropical region in South China according to which fertility of the soils are evaluated. The hyrolyzable N extracted by 6 N HCl in soils under the tropical rain forest and high grass was about 60-80% of the total N, and it was only 30% of the total N in lateritic upland field. It may be because the frequent ploughing on lateritic upland field accelerates the rapid decomposition of nitrogenous compounds in soil. Results of the study are summarized as follows.