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四、土壤营养与施肥 在施肥的情况下,作物生育过程中所需要的氮、磷、钾等养分,很大一部分仍然要靠土壤供给。因此,要想合理施用肥料,必须了解作物与土壤营养之间的关系。 1.土壤中养分含量 土壤中养分的丰欠主要看有机质、氮、磷、钾的含量。我省农业土壤中有机质含量多在1～2％,有由西向东逐渐增加的趋势,东部山区有的可达3～4％。土壤中全氮一般为有机质含量的8～12％,土壤有机质的多少直接影响氮素含量。我省土壤全氮量为0.08～0.15％。各类土壤中有机质和含氮量较低,因而施用氮肥普遍有显著增产作用。 土壤全磷中大部分以难溶性状态存在,只有一小部分是能被作物直接吸收利用的有效磷(也称速效磷)。我省土壤中全磷为0.05～0.3％,全磷不能反应为作物提供可利用磷的程度,而有效磷的多少,可作为要否施用
Fourth, soil nutrition and fertilization In the case of fertilization, crop fertility required for the process of nitrogen, phosphorus, potassium and other nutrients, a large part still rely on soil supply. Therefore, in order to use fertilizers reasonably, one must understand the relationship between crop and soil nutrition. 1. Nutrient content of soil Nutrient abundance of soil mainly depends on organic matter, nitrogen, phosphorus and potassium content. Organic matter content of agricultural soil in our province more than 1 to 2%, with a gradual increase from west to east trend, some up to 3 ~ 4% in the eastern mountainous areas. Soil total nitrogen is generally organic matter content of 8 to 12%, the amount of soil organic matter directly affects the nitrogen content. Soil nitrogen in our province is 0.08 ~ 0.15%. All kinds of soil organic matter and nitrogen content is low, so the application of nitrogen fertilizer generally have a significant increase in yield. Most of the soil total phosphorus in the insoluble state exists, only a small part of the crop can be directly absorbed by the use of available phosphorus (also known as available phosphorus). Total phosphorus in the soil of our province is 0.05 ~ 0.3%, total phosphorus can not react to provide crop available phosphorus level, and the amount of available phosphorus can be used as whether to apply