| According to relying excessively chemical fertilizer, ignoring the organic fertilizer on agricultural production in China, and the environmental problems has been caused by soil degradation which was caused long-term inputs of chemical fertilizer, and reducing productivity of farmland, around the core of improving soil uniformingly growing seed preservation of dry-farming land and production efficiency of precipitation. The four successive years of positioning experiments of the different amounts of returning corn straw and organic fertilizer was carried out in a typical sub-humid land Heyang of Shanxi. We analyzed the influences of organic fertilization on soil moisture, corn biology growth characteristics, and yield and soil physical and chemical properties in corn growth stages. A further study on mechanism of organic fertilization on upland soils environment, through improving reasonably soil fertility, improving soil structure and soil extender storage capacity and further improving the production efficiency of precipitation, which provided theoretical basis and practical guidances for the north rain fed agricultural. Research has achieved the following main results:1. Corn yield were increased highly significantly through organic fertilization. The results of organic fertilization for four consecutive years show that, organic fertilizer increased yield of spring corn increasing range of yield is 18.33%-42.59%, water use efficiency is 16.30% -35.97%, corn yield increased with the amount of fertilization. The treatment of straw returning increased yield of corn increasing range is 11.86%-22.45%, water use efficiency is 16.30% -35.97%, a significant effect on yield by straw returning in the next year, corn yield decreased with the amount of straw returning. With the increase of year corn yield increased with the amount of straw returning. WUE of corn were not significant about the difference amount of straw returning and organic fertilizer. WUE of organic fertilizer were higher than WUE of straw returning.2. Organic fertilizer has good water conservation function on the soil moisture. Compared with organic fertilizer treatments, straw returning treatments were better with processing water, increasing the quantity function. The soil water content of 0-80 cm soil layer for each organic fertilizer treatment was higher than that in control during corn jointing stage. Compared with the soil water content of 0-80 cm soil layer in control, the treatments of straw returning and organic fertilizer increased by 1.45%-9.73% in 2008. To the soil moisture of 0-80cm soil layer, Compared with control, the treatment of straw returning of 13 5000 kg·hm-2 was higher 1.11% in 2009, was higher 3.06% in 2010 and has significant differences. Especially soil moisture has been increased significantly in 40-60 cm soil layer. Compared to control, during the corn period of huge bellbottom stage, irrigation stage, filling stage and harvest stage in 0-100 cm soil layer, the soil moisture of the different amount of straw returning 13 500 and 9 000 kg·hm-2 had certain increased, which were lower than that control in 100-200 cm soil layer. The different amount of organic fertilizer 22 500 and 15 000 kg·hm-2 were lower than that control in 100-200 cm soil layer. Straw returning treatments all can raise soil moisture of above 60 cm layer in the whole growth stage. The difference amount of straw returning and organic fertilizer were not significant.3. The soil bulk density of organic fertilizer treatment was lower than that in control for four years in a row. The soil bulk density was decreased with the increase of the straw application treatment and organic fertilizer treatment, and between each fertilizer treatment had no obvious difference. In 2008, the soil bulk density of 0-40 cm soil layer under each organic fertilizer treatment was lower by 0.75%-3.52% than that in control, and it decreased by 0.75%-3.88% and 2.74%-9.56% in 2009 and 2010, respectively.4. >0.25mm soil aggregates contents of upland were increased through Organic fertilization. Soil aggregates contents were increased with the increase of the amount of straw returning and organic fertilizer. In 2009, compared with the control, the soil mechanical aggregates contents and the water-stable aggregates contents of the treatments of organic fertilization, increased by 7.34%-14.19% and 25.97%-75.58% in 0-10 cm soil layer, respectively, and increased by 11.34%-23.57% and 10.88%-38.91% for 10-20 cm soil layer, respectively. In 2010, the straw returning treatments of 135 000 and 9 000 kg·hm-2, and the organic fertilizer treatments of 22 500 and 15 000 kg·hm-2 were also significantly higher than he control in 0-20 cm soil layer: to the soil mechanical aggregates contents and the water- stable aggregates contents, increased by 5.41%-12.29% and 59.32%-122.46% in 0-10cm soil layer, respectively, and increased by 8.24%-9.38% and 45.02%-90.05% for 10-20 cm soil layer, respectively.5. The effects of organic fertilization on soil nutrient contents were in different ways. Effects of the treatments of organic fertilization on the soil nutrient regulation were significantly, increasing soil organic matter contents and soil nitrogen reserves by four consecutive years organic fertilization. The contents of alkali-hydro nitrogen, rapidly-available phosphorus and rapidly-available potassium were increased significantly (P<0.05). The contents of soil organic matter were improved significantly through organic fertilization. The contents of soil organic matter of four years to 0-40 cm soil layer were all significantly higher than that in control: increased by 3.85%-24.31% and 0.86%-13.80% to 0-20 cm and 20-40 cm soil layer, respectively. Alkali-hydro nitrogen contents of 0-40 cm soil layer under organic fertilization were all significantly higher than that in control, and increased with the straw returning and organic fertilizer treatments. Compared with the control, Alkali-hydro nitrogen contents of 0-20 cm and 20-40 cm soil layer under organic fertilizer treatment were higher 0.55%-22.33% and 5.57%-36.84%, respectively. Effects the contents of soil available phosphorus increased with increasing the amount of straw returning and organic fertilizer. Compared with straw returning. Effects of organic fertilizer treatments on rapidly-available phosphorus contents increased significantly. The rapidly-available phosphorus contents of straw returning were declined year by year. Organic fertilization significantly increased rapidly-available phosphorus contents, especially the treatments of organic fertilizer increased significantly, rapidly-available phosphorus contents of 0-20 cm and 20-40 cm soil layer were higher than 16.64%-570.04% and 1.88%-186.34% than that in control, respectively. Rapidly-available potassium contents of each soil layer under organic fertilization were significantly increased: increased by 12.45%-38.84% and 5.12%-48.31% to 0-20 cm and 20-40 cm soil layer.6. Organic fertilization can significantly enhance the activity of soil phosphatase, invertase and urease. Their activity was decreased with the increase of soil layer except soil catalase, whose activity was increased with the increase of soil layer. In 2009, the activity of soil phosphatase for 0-60 cm soil layer under each organic fertilization was higher than that in control, increased by 4.29%-81.42%, significantly increased for organic fertilizer treatments. The activity of soil invertase for 0-60 cm soil layer under each organic fertilizer treatment was also higher than that in control, increased by 6.29%-32.90%. However, the activity of soil catalase for different soil layer was different: the activity of 0-20 cm soil layer was lower than that in control, 20-60 cm soil layer was higher 0.26%-2.11% than that in control. The activity of soil urease for 0-60 cm soil layer was higher 1.27%-45.28% than that in control. In 2010, compared with the control of 0-60 cm soil layer under organic fertilizer: the activity of soil phosphatase was higher 21.76%-57.45%, the activity of soil invertase was higher 15.33%-84.73%, the activity of soil catalase was higher 1.98%-3.70%, the activity of soil urease was higher 3.63%-53.33%. Increasing invertase activity of straw returning treatments was particularly significant. Compared to straw returning treatments, the phosphatase and urease activity of organic fertilizer treatments increased significantly. |
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