新建日光温室土壤养分平衡与累积特性

Nutrient accumulation and balances in soils of the new-established greenhouses

连续3年定点监测位于黄土高原南部陕西杨凌的10余个新建日光温室栽培蔬菜种类、产量及施肥情况,并在每季作物种植前及收获后测定0-100 cm土壤电导率、有机质、全氮、有效磷、速效钾及0-200 cm土壤硝态氮等理化性质。结果表明,过量施用有机肥及化肥导致新建温室土壤养分大量盈余,前3年土壤氮、磷、钾养分（以N、P2O5、K2O计）表观盈余量之和分别高达3 784、4 097及2 727 kg/hm2。种植前3年有机质、全氮呈线性增加,年均增加量分别为4.25、0.25 g/kg;土壤有效磷、速效钾累积更加突出,种植2年后,耕层有效磷及速效钾已达高或极高水平;随着种植年限的增加,土壤剖面硝态氮累积量显著增加,耕层以下土壤有效磷、速效钾含量也有所增加。说明新建日光温室在种植初期就存在施肥过量问题,由此引发的问题值得关注。

The paper studied the fertilization status,vegetables types,yield and planting acreage of more than 10 new greenhouses located in the southern Loess Plateau of Yangling under 3-years constant surveillance,and determined the physical and chemical properties such as 0 ~ 100 cm soil conductivity,organic matter,total nitrogen,available phosphorus,available potassium and 0 ~ 200 cm mineral nitrogen both before planting and after harvest. The results showed that excessive fertilization existed from the earlier stage of planting in the new greenhouses,excessive organic fertilizer and chemical fertilizer input leaded to a large surplus of nutrients,and the total amount of the apparent surplus of soil nitrogen,phosphorus and potassium nutrient（ in N,P2O5,K2O） in the first three years reached 3 784,4 097,2 727 kg / hm2,respectively, which also revealed the cause of the rapid nutrient accumulation in new greenhouse planting. During the first 3 years＇ planting,soil organic matter and total nitrogen increased linearly,the average annual increase were 4. 25 and 0. 25 g / kg separately,while the available phosphorus and potassium accumulated more significantly and reached up to a quite high level after 2 year＇planting. With the increase of planting years,soil nitrate accumulated in a significant increase in soil profile,available phosphorus and available potassium in the soil below the plow layer also increased. It showed excessive fertilization existed from the earlier stage of the plantation in the new greenhouse,and the problem arisen was noteworthy.