生物炭和无机肥对盐碱滩涂围垦农田土壤性状的影响

在重度盐碱滩涂围垦的土地上,添加不同量的生物炭(0、3、6、9 hm~(-2)),在玉米不同生育期施加无机肥,对照CK不施肥,研究土壤在不进行作物种植下的性状变化。结果表明:自然条件下重度盐碱土地土壤物理性状变差,施用无机肥加剧了土壤的退化程度;在未种植作物条件下,生物炭添加没有对降低土壤容重起到促进作用,同时也没有提高土壤饱和含水量及田间持水量;团聚体组成分析显示生物炭用量在3 t hm~(-2)时土壤中2 mm团聚体增加最多;雨季时雨水淋洗显著降低土壤0~20 cm土层盐分,生物炭用量越大土壤盐分淋洗效果越明显;八月份和九月份时随着雨季结束,地下水位升高、太阳辐射增强加速了盐分在表层土壤的积聚,生物炭添加能有效抑制盐分在表层的积累,但无机肥添加又阻碍了这种抑制作用。

Effects of Biochar and Chemical Fertilizer Application on Soil Properties in Farmland Reclaimed from Salinity Coastal Tidal Flat

Different chemical fertilizers were applied frequently in different stages of crop growth to improve crop productivity.But the utilization of chemical fertilizer brought many negative effects on soil quality.In heavy saline-alkali soil region,many fields were reclaimed to farmland.Accompanied with agricultural activities,how to improve soil fertility and decrease soil salinity was still unsolved.Biochar had been used for many purposes in agriculture due to its special property.In this paper,different amount of biochar (0,3 t hm-2,6 t hm-2,9 t hm-2) was added to surface soil combined with or without chemical fertilizer (nitrogen and phosphorus fertilizer) in different stage of maize growth.Resuhs showed that soil physical property became worse in heavy saline-alkali soil under natural condition.Chemical fertilizer accelerated soil degradation.The biochar application did not decrease soil bulk density and not increase saturated soil moisture and water holding capacity under uncultivated crop.Biochar of 3 t ha-1 mostly improved the formation of ＞ 2 mm soil aggregate.The leaching by rainwater largely depressed soil salt at 0-20 cm soil depth during the rainy season.Further,the larger amount application of biochar had the more leaching effect on soil salt.At the end of rainy season in August and September,soil salt accumulated in the surface soil (0-20 cm) due to the rise of ground water level and the strength of solar radiation,the application of biochar inhibited the salt accumulation in surface soil,but the application of chemical fertilizer blocked the inhibiting effects.