Issues and Some Strategies of Sustainable Development of Black Soil Resources in Black Soil Zone in Northeast China

黑土资源是世界的稀缺资源,黑土带的水土流失、环境污染、土地流转、土地退化问题成为黑土资源可持续发展的障碍。根据实地调研结合资料,分析了东北黑土带土地资源可持续发展的主要问题;提出了黑土资源的可持续发展对策,即:加强农业发展规划;保护黑土区耕地,农耕技术上改进,加强农田基本建设等。     

福建土壤对酸沉降的相对敏感性评价与区划

选择母岩、土壤类型、土地利用和降雨量 4个生态因子 ,应用半定量化方法对其进行类目划分和权重 ,综合评价了福建省土壤对酸沉降的相对敏感性 ,并应用地理信息系统进行了区划 .由于福建省风化缓慢的硅质岩所占的比例较大 ,土壤大多呈酸性至微酸性反应 ,降水丰富 ,加之针叶林面积大 ,所以全省有 60 %以上面积的土壤显示出较大的敏感性等级 (5～ 7级 )     

Residue management for reducing evaporation in relation to soil type and evaporativity1

Abstract. Usual residue-management options are to remove the residue, use it as mulch with or without undercutting or to incorporate it into the soil. While the role of surface mulch in evaporation has been widely studied, the information on the effect on evaporation of mulch with undercutting or residue incorporated into soil, particularly in relation to soil type and evaporativity (E_o) is lacking. We studied the effect of wheat straw used in various ways on the course of evaporation loss from soil columns with three soils at Ludhiana, India and one soil at Bushland, Texas, USA, under two E_o's Energy-limited evaporation rates under mulch (E_om) followed the soil-specific relation E_om/E_o= a e^(bRes+cEo), where Res is residue rate t/ha and a, b and c are constants; E_o, is expressed in mm/d. In an effort to model the total evaporation (CE) during the energy-limited stage ‘U’ was obtained from appropriate CE versus time curves and (CE-U) was regressed over (t - ti)^0.5 to obtain the slope ‘α’ (Ritchie 1972) for the soil-limited evaporation stage. The observed ‘U’ was independent of mulch rate and E_o but was strongly affected by soil type, Values of ‘α’ decreased with increase in mulch rate and decrease in E_o and coarseness of soil. The otherwise short lived benefit of evaporation reduction with mulch per se, which peaked after a few days was maintained when residue was mixed with soil at the stage when evaporation reduction reached a maximum; this benefit continued for several weeks. Cumulative evaporation values computed from ‘U’ and ‘α’ agreed closely with the observed values under straw mulch for loamy sand and clay loam soils and for ‘undercut’ and ‘residue mixed’ treatments on all soils regardless of E_o, and for all situations under small E_o. However, for sandy loam and silt loam soils under E_o of 10 mm/d, the modified square root of the time function of Jalota et al. (1988) gave a better fit.     

重迎茬亚麻生长发育障碍机制的研究

重迎茬亚麻减产是由多种因素综合作用的结果,亚麻重迎茬可使病害加重是最主要因素,重茬年限越久发病越严重;重迎茬造成了土壤营养元素的单一消耗,随着重迎茬年限的增加,土壤中速效氮、速效磷、速效钾等含量降低。     

覆盖免耕在休闲期的节水和生育期的调温效应

对免耕覆盖、秸秆还田和常规耕作在休闲期的节水效果研究表明:在夏季休闲期,免耕覆盖比常规耕作多贮水30.62mm,比秸秆还田多23.91mm;在冬季储水灌溉期间,可将储水定额从2100m3/hm2减少到600和975m3/hm2。对春小麦生育期土壤表层,5、10、15、20和25cm处温度变化观测发现:免耕覆盖土壤温度在气温较低的8:00可以提高土壤表层温度,在气温较高的14:00可以减缓土壤温度的升高,而在19:00气温降低时可以减缓土壤温度的降低,使土壤温度一直保持在一个稳定的状态,这有利于调节农田小气候,创造作物良好的生长环境。     

农业科技示范园区产业化管理浅析——以内蒙古太仆寺旗为例

农业科技园区作为农业产业的一种新的组织形式近年在内蒙古太仆寺旗（以下简称太旗）得到了充分的发展。文章分析了园区的示范作用，从经济效益、社会效益和生态效益三个角度介绍了太旗农业科技园区发展的现状。在实地调查的基础上，指出了太旗农业科技园区产业化经营中，在农产品生产和营销、政府调控、园区管理等方面存在的问题。最后，作者针对性的给出如何有效实现示范园区产业化管理的政策建议。     

尕海地区弃耕地土壤可溶性盐分测定

１９９０～１９９３年在柴达盆地尕海地区弃耕地进行土壤可溶性盐分测定，测定结果，该地区土壤盐分组成为氯化物－硫酸盐和硫酸盐－氯化物，大部分地区耕层盐分含量小于１０ｇ．ｋｇ＾－１，少部分盐荒地表层含盐量高达７０ｇ．ｋｇ＾－１，牧草生长季节中，土壤盐分含量最低期在６月份。     

碧峰峡森林土壤性状研究

碧峰峡不仅是旅游景点,还是多学科研究的天然“实验室”,地处雅安亚热带区,原始森林植被保护完好,土壤垂直分布明显,地质现象复杂,也是大熊猫、金丝猴出没之地。经研究结果：土壤呈酸性,自然肥力高．经相关分析结果：土壤有机质含量和ＣＥＣ等有关理化特性的相关性,较物理性粘粒与ＣＥＣ间更加显著。     

The fate of fluroxypyr in the soil in an oil palm agroecosystem

A study on the fate of fluroxypyr in Malaysian agricultural soils was carried out under natural conditions in an oil palm plantation. Three experimental plots in the oil palm estate were selected and three types of treatments were administered, namely fluroxypyr at the recommended dosage, double the recommended rate, and the untreated control. Residues of fluroxypyr in the soil, water, and oil palm leaf were monitored at regular intervals up to 90 days after treatment (DAT). The recovery of fluroxypyr in the water and soil samples ranged from 91–102% when fortified at 1–25 p.p.b. and 91–98% when fortified at 4–50 p.p.b. The recovery from the oil palm leaf ranged from 76–114% when the oil palm leaf sample was fortified at 0.05–1.0 p.p.m. The results showed that fluroxypyr leached down to 50 cm depth at 1 DAT when the plots were treated with either dosage. However, fluroxypyr was not detected in the soil residue at 14 and 21 DAT. Fluroxypyr was not detected in the oil palm leaf samples irrespective of the rates of herbicide application or sampling intervals. The residue of fluroxypyr was detected in water from a nearby stream up to 5 DAT at levels ranging from 0.06–0.21 µg L⁻¹. This result suggests that fluroxypyr persists for a short period in the soil and water ecosystems, but not in the oil palm leaf.