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黄土性母质上发育的棕壤(棕黄土)的肥力高低,主要决定于有机质含量。我们对高肥力棕黄土的有机质含量,腐殖质组分指标,影响土壤有机质消长的土壤氮素矿化率,各种有机物料及主要作物根茬的腐解残留率进行了研究,为提高和维持土壤有机质水平提供依据。主要研究结果是:(1)高肥力棕黄土有机质平均含量0～20厘米为1.58%,20～40厘米为1 .18%。腐殖质组分中,胡敏酸碳/富里酸械平均。0～20厘米为0.52,20～40厘米为0.41。(2)棕黄土氮素年矿化率盆钵法测定结果是高肥力的为2 .56～3 .78%,中低肥力为2.35～2.63%。中肥力田间试验为2.05%,较盆钵法低。(3)不同有机物料的腐解残留率,盆钵及砂滤管法测定结果:秸秆及牛马粪为32～45%,猪粪变化较大,为16～30%,绿肥不到20%。用砂滤管测定根茬腐解残留率玉米、高粱、大豆及谷子分别为30%、26%、33%和41%。
The fertility of brown earth (brown loess) developed on loamy parent material is mainly determined by organic matter content. We studied the organic matter content, humus component index, soil nitrogen mineralization rate affecting soil organic matter growth, decomposed residue rate of various organic materials and stubble of main crops in high fertility brown loess. In order to improve and maintain soil organic matter Level to provide basis. The main results are as follows: (1) The average organic matter content of high-fertility brown loess is 1.58% for 0-20 cm and 1.18% for 20-40 cm. Humic components, humic acid carbon / fulvic acid averaging. 0 to 20 cm to 0.52 and 20 to 40 cm to 0.41. (2) The annual mineralization rate of N in brown-loess soil is determined by the pot method with high fertility of 2.56-3.78% and low and medium fertility of 2.35-2.63%. Fertility field trials of 2.05%, lower than the pot method. (3) Residue decomposition rate of different organic materials, pot and sand filter tube test results: straw and cow horse manure 32 ~ 45%, pig manure varied greatly, 16 ~ 30%, green manure less than 20%. The residual rate of decomposition of stubble by sand filter tube was 30%, 26%, 33% and 41% respectively for maize, sorghum, soybean and millet.