控释肥在基质栽培中的养分淋溶及其对基质理化性质的影响

无土栽培是设施农业中广泛采用的先进技术,能有效克服土壤连作障碍,具有省水、省肥、省工等土壤栽培难以比拟的优势,控释肥在基质栽培中的应用,使无土栽培技术的发展前景更加广阔。本文通过无土栽培试验,研究了控释复合肥在基质中的养分变化规律及其对基质理化性质的影响。研究结果表明,控释肥氮、磷、钾、铁和锌的释放规律基本一致,且养分的控制释放减少了养分流失,降低了基质中的盐分浓度,与普通速效肥相比更具有安全性;控释肥明显改变了基质的容重、孔隙度,改善了基质的水气状况,从而为作物的生长提供了良好的生长环境。     

氮磷肥施用对保水剂钝化土壤重金属铅镉效果的影响

[目的]探讨氮磷肥施用对保水剂钝化土壤重金属铅镉效果的影响,为揭示土壤水肥保持和重金属污染治理的协调性机制,制定SAP应用技术规程等提供参考。[方法]采用土柱淋溶试验方法,比较添加氮肥和磷肥对SAP钝化土壤铅(Pb)、镉(Cd)效果的影响。[结果]在Pb,Cd复合污染土壤中SAP用量为1.0g/kg时,控氮释磷效果较好,相比无SAP的对照处理,Pb累积淋失量减少5.1%,Cd累积淋失量增加13.6%;氮磷肥添加试验表明,添加氮肥的SAP处理Pb累积淋失量增加76.7%,Cd累积淋失量增加47.6%,添加磷肥的SAP处理Pb累积淋失量减少26.0%,Cd累积淋失量减少20.5%;添加复合氮、磷肥的SAP处理Pb累积淋失量减少2.3%,Cd累积淋失量增加8.3%。[结论]保水剂具有控氮释磷效应,且对土壤中的Pb,Cd有一定钝化作用;氮肥降低SAP钝化Pb,Cd的效果,而磷肥增强SAP钝化Pb,Cd的效果;氮、磷肥复合对SAP钝化Pb的效果影响不显著,但会降低SAP钝化Cd的效果。     

Improvement of mineral nutrient content of tomato through selection of cultivars and soil fertility

Depleted soil fertility and high-yielding cultivars have been associated with low nutrient contents in vegetables. This study explored if elemental nutrient concentrations in tomato (Lycopersicon esculentum Mill.) can be increased through selection of cultivars and nutritional regimes. Cultivars with different phenotypes of heirloom and modern origins were studied in field experiments in two years. Chemical fertilizer (10-10-10), compost, and an organic fertility regime of soybean meal, bone meal, and potassium sulfate were assessed for their effects on growth and composition of fruits of the cultivars. Differences in nutrient concentrations between modern or heirloom cultivars or among fertility treatments were small or non-significant. Differences among individual cultivars for each element were large with some cultivars having nearly twice the concentrations of nutrients of others and with considerable uniformity in cultivar rankings among the elements. This work suggests that cultivars can be selected for production of nutrient-dense tomatoes.     

Study of the Productive Behavior of Var-21 Soya (Glycine max (L.) Merrill) under the Application of Organic Fertilizers

The use of organic fertilizers to improve the agronomic parameters of soy (Glycine max (L.) Merrill) has been considered a key production practice. During the period from December 2015 to May 2016, the productive behavior of Var-21 soya under the application of two organic biofertilizers was assessed in southern Haiti. Four random repetitions were carried out with biofertilizer A (cow dung + leguminous waste + ash + rice chaff) and biofertilizer B (cow dung + molasses + quick lime). The variables analyzed were days to flowering, plant height, number of beans per pod, weight of 1,000 beans, and yield per hectare, with statistical evaluation by analysis of variance and Tukey’s test. The best yield was obtained with biofertilizer A in treatment T2 (150 L/ha) (4,129.99 kg/ha). This study enabled us to identify the most efficient foliar fertilizer to improve the production parameters of Var-21 soya. The information obtained will serve as a basis for future research, especially into the effectiveness of organic fertilizers on other crop species, and under other agro-environmental conditions.     

有机无机氮肥配施对莴苣土壤N2O排放的影响

采用静态箱–气相色谱法研究不同种类有机无机氮肥配合施用对盆栽莴苣土壤N_2O排放规律及排放量的影响。试验设置不施肥(CK)、不施氮肥(PK)、施纯化肥(NPK)、有机无机肥配施1(20%猪粪氮+80%化肥氮,NPKM1)、有机无机肥配施2(20%沼渣沼液氮+80%化肥氮,NPKM2)和有机无机肥配施3(20%猪粪堆肥氮+80%化肥氮,NPKM3)共6个处理。结果表明:莴苣生育期各处理施肥后土壤N_2O排放出现多个峰值,出峰时间和大小不一;累积排放量随着生育期的进程逐渐增加,处理间差异更为明显。莴苣生育期各处理土壤N_2O平均排放通量及累积排放量范围分别为0.10～0.25 mg/(m2·h)和1.37～3.42 kg/hm2,大小均表现为NPKNPKM2PKNPKM1NPKM3CK。土壤N_2O排放系数范围为0.13%～0.68%,大小表现为NPKNPKM2NPKM1NPKM3。与NPK处理相比,NPKM1、NPKM2和NPKM3处理莴苣土壤N_2O累积排放量均分别降低48.08%、25.75%和48.30%,产量分别增加48.66%、22.13%和53.76%。总之,施用纯化肥会促进菜地土壤N_2O的排放,而不同种类有机无机氮肥配施能有效减少N_2O排放且提高作物产量,以猪粪类配施效果最佳。因此,有机无机配施是菜地N_2O减排、降低蔬菜种植中氮素损失的重要途径。     

The effects of fertilization on the health status,nutrition and growth of Norway spruce forests with yellowing symptoms

We studied the effects of magnesium (Mg) NPK fertilizer applied in 2000 to maturing Norway spruce (Picea abies /L./ Karst.) stands with yellowing symptoms and situated on poor acidified soils in the ?umava mountains (the Czech Republic). Long-term defoliation, nutrient content in the foliage and diameter increment were evaluated in three specific variants: yellowing trees, trees without yellowing symptoms and fertilized trees. The results indicate differences in soil characteristics, nutrient content and radial growth with response to climate. Fertilization increased Mg content and base saturation in the soil and decreased the amount of exchangeable aluminum and hydrolytic acidity. Differences were significant especially in magnesium, calcium and phosphorus contents in the foliage of yellowing trees. There was also a significant difference in manganese content; yellowing trees showed deficiency in comparison with both fertilized and unfertilized healthy trees. Two years after the initial fertilization (to present), defoliation and yellowing symptoms in the unfertilized yellowing trees were more pronounced compared to other variants. These symptoms were more influenced by fertilization than foliation. The duration of significant positive effects of fertilization on diameter increment lasted for a shorter time than the effect on foliage. Simultaneously, higher sensitivity to climatic factors was observed in the fertilized trees.     

青海省农业面源污染源特征分析

基于历史数据分析,阐明青海省农业面源污染来源的主要特征及发展趋势,提出基于不同畜禽养殖方式的畜禽养殖面源污染排放量的计算方法,揭示不同类型农业面源污染源的污染物产生量和潜在威胁,并提出主要污染来源的防治对策。青海省近30a来的农药化肥、地膜、秸秆以及畜禽粪便量总体上呈现增大的趋势,近5a来秸秆量出现小幅下降;在不同的畜禽养殖方式下,散户产生的面源污染负荷量最大,规模化养殖厂(小区)和养殖专业户的NH_3-N污染负荷较大,放养畜禽的NH_3-N和总磷面源污染负荷量不容忽视。2015年青海省畜禽粪便产生的进入水体形成农业面源污染的化学需氧量占98.8%,NH_3-N、总氮和总磷分别占90.2%、93.8%和93.9%。在主要农业面源污染防控措施方面,应大力加强畜牧业的污染治理,形成种植业与畜牧业的结合,建立良性生态循环模式。     

基于RVM的配比变量排肥掺混均匀度离散元仿真及验证

采用试验测量或现有的间接标定方法很难实现配比变量排肥离散元仿真的参数标定,针对此标定难题,该文提出一种基于肥料掺混均匀度-仿真参数相关向量机模型主动寻优的标定方法。将配比变量离散元排肥过程看作特定的非线性系统,采用相关向量机机器学习方法揭示模型参数与肥料掺混均匀度之间的映射关系,建立回归元模型;基于最优模型参数值对应的肥料掺混均匀度值应与试验值一致,采用建立的元模型结合试验统计结果构建适应度函数;基于约束最优的数学思想建立数学模型,通过最优参数值遗传算法迭代计算,得到最优值。5种排肥转速下(30、40、50、60、70 r/min),排肥器采用碰撞边缘为外凸曲线形的A型掺混腔时,标定模型排肥后肥料掺混均匀度与试验值的相对误差均值:氮肥为6.4%,磷肥为4.1%,钾肥为5.9%;标定前氮肥为26.8%,磷肥为28.9%,钾肥为36.1%。采用碰撞边缘为直线形的B型掺混腔时,标定模型排肥后肥料掺混均匀度与试验值的相对误差均值:氮肥为5.8%,磷肥为5.6%,钾肥为4.9%;标定前氮肥为21.9%,磷肥为32.5%,钾肥为28.9%;采用碰撞边缘为内凹曲线形的C型掺混腔时,标定模型排肥后肥料掺混均匀度与试验值的相对误差均值:氮肥为5.0%,磷肥为3.7%,钾肥为8.7%;标定前氮肥为36.2%,磷肥为31.6%,钾肥为24.4%,该方法能够实现配比变量排肥离散元仿真参数准确有效的标定。     

我国与欧美化肥重金属限量标准的比较和启示

本文介绍了欧盟各国以及美国部分州的化肥重金属限量标准的制定过程和阈值,分析了我国相关标准制定中存在的不足。我国化肥重金属限量标准是针对肥料种类来制定的,肥料种类之间重金属限量值及限制的重金属种类均存在很大差异。限量标准有国家标准,也有行业标准。不少单质化肥及复合肥标准中没有重金属限量指标,但对由单质化肥配制的水溶性复混肥料则制定了非常严格的限量标准。我国重金属限量标准的制定缺乏理论依据和试验数据支撑,标准公布后也缺少制定依据的说明和解释。美国是根据磷肥及微量元素肥料种类和用量两方面来设定重金属限量标准,该标准由美国环保局(USEPA)等机构根据化肥中有害元素对人类健康风险评估模型制定的,并参考了长期的田间定位试验数据和食物中重金属的风险评估调查数据。美国植物食品控制管理协会(AAPFCO)根据上述风险评估结果提出了化肥中重金属的限量标准,美国各州则在参考该标准的基础上根据各州法律法规实施。欧盟目前没有统一的化肥重金属限量标准,各国各自规定了相关标准。建议我国参考发达国家的标准制定方式建立重金属的危害风险评价体系;根据大量、中量与微量元素肥料类别及施用量,区分不同重金属的限量,且所有化肥所含的重金属进入农田的限量标准应保持一致。建议制定标准应进行环境、食品安全等调查与长期定位试验,以科学数据为依据,制定适合我国国情的化肥重金属限量标准。