Where can tigers persist in the future? A landscape-scale, density-based population model for the Indian subcontinent

Despite being targeted as a conservation flagship species for several decades, the tiger (Panthera tigris) grows ever more imperiled. Debate exists as to where tiger conservation should focus: on protected nature reserves or larger landscapes. We developed a landscape scale, density-based model to assess whether reasonably effective management of current reserves is adequate to ensure the survival of tiger populations. We focused on the Indian subcontinent, the region likely to harbor most tigers. Using tiger density estimates and vegetation data, we set tiger population targets that could be attained through reasonable management of the subcontinent’s nature reserves. Depending on the quality of the surrounding landscape matrix, our model indicated that the subcontinent could potentially hold ∼3500-6500 tigers, in up to 150 reserves. Strikingly, just 21 reserves can hold most (58-95%) of this tiger capacity. These high-population target reserves were relatively insensitive to the hostility of the surrounding matrix to tigers, as their aggregate capacity varied by <10% across a wide range of matrix conditions. In contrast, the remaining 129 reserves were highly sensitive to matrix quality, as they were unable to sustain populations with a tiger-hostile matrix, even with reasonable management. Our results suggest that reasonably improved management of the subcontinent’s reserves can sustain multiple tiger populations based on two differing conservation strategies. Conservation within the 21 reserves with the largest population targets should focus primarily on the reserves themselves. In contrast, tiger conservation in the remaining reserves can succeed only with additional management of the unprotected landscapes that surround them.     

草纤维膜与塑料地膜覆盖农田的生态效应比较

根据多年定位试验资料，讨论了一种新型的农田覆盖材料──草纤维膜，覆盖农田对土壤理化性质、土壤温度、土壤水分状况以及作物生长发育的影响，并与塑料地膜覆盖农田的生态效应进行了比较。结果表明，草纤维膜与塑料地膜覆盖具有改善土壤结构，增强作物对土壤肥料的有效利用，改善作物生长的土壤温度状况，减少土壤无效蒸发和提高水分利用效率的作用。与塑料地膜相比，草纤维膜覆盖没有污染土壤的副效应，因此是解决我国北方旱农地区“旱”与“薄”问题的有效方法。     

Soil Cover with Organic Mulch and Its Influences on Soil Physical Parameters (Ⅲ)——Soil Temperature Regime under Organic Mulch

以田间实验为基础，分析了在不同厚度的有机物覆盖层下土壤温度变化的机制并与未覆盖条件下的土壤温度进行了比较。实验结果表明，有机物覆盖使土壤的日最高温度和日平均温度降低，但却使土壤的日最低温度得以提高。     

川中丘陵坡耕地水土保持与农业生产的发展

总结了作者近 10多年来在水土保持和作物栽培中所做的研究工作 ,在分析研究川中丘陵坡耕地水土流失状况基础上 ,提出了一套既有益于水土保持 ,又能提高作物产量 ,提高农户经济收益的工程措施和农耕措施 ,对今后如何协调川中丘陵坡耕地水土保持与农业生产的发展有重要指导意义。     

棉花膜下滴灌毛管布置方式的试验研究

根据2000年5～8月在新疆石河子121团土壤改良实验站进行了大田棉花膜下滴灌毛管布置形式的试验研究,毛管间距110cm基本能满足外行棉花对水分的需求。通过对3种不同毛管间距条件下棉花株高、叶面积、根长、产量和品质的比较,毛管间距110cm,一条毛管灌溉4行棉花的布置方式较好。它比常规布置方式可节省毛管用量1/3左右,可以大幅度降低膜下滴灌系统的投资     

黄土高原区农田覆盖效应与前景分析

依据黄土高原区的水热条件,结合已有研究结果,简述了黄土高原地区农田不同覆盖类型,诸如秸秆覆盖、聚氯乙烯薄膜覆盖、生物覆盖等,分析了农田覆盖技术的生态环境效应和经济效应,农田覆盖可提高土壤含水率,增加土壤耕层温度改善土壤肥力状况,减少水土流失,促进作物生长,并指出生物覆盖、秸秆还田和聚氯乙烯薄膜覆盖技术在该区的应用前景。     

半干旱区旱地春小麦全膜覆土穴播对土壤水热效应及产量的影响

以春小麦"陇春27"为试材,研究半干旱区旱地全膜覆土穴播对土壤水热效应及小麦产量的影响。结果表明:与裸地平作(CK)相比,全膜覆土穴播(PM)和全沙覆盖平作(SM)增温效果呈"挂钩型",增温效果在小麦拔节期前最为明显,PM 0-25 cm土壤平均温度较CK提高1.8 ℃,全沙覆盖平作提高1.4 ℃,拔节后PM和SM的增温效果逐渐减弱直至消失,而在成熟期又呈现较弱的增温效果。PM和SM能提高小麦出苗后耗水速度并加大耗水量,其中,小麦拔节到扬花期耗水量增加最多,分别较CK平均增加54.93%和31.54%,且此阶段越是干旱,促进耗水作用越明显,PM促进作用大于SM。PM和SM能显著提高小麦阶段性水分利用效率(WUE_b),其中PM以苗期提高最多,2a平均较CK提高365.17%,SM拔节期提高最多,2年平均较CK提高119.00%。PM和SM在增温、促进耗水作用下使小麦各生育期提前并增加单株干重,产量较CK分别平均增加432.28%和375.82%, 水分利用效率(WUE)分别平均增加351.51%和338.29%,而且越干旱年份增产效应愈加明显。可见,PM和SM在越为干旱的年份促进耗水、增产和提高WUE的作用越显著,PM效果强于SM。     

免耕条件下不同秸秆覆盖量的土壤有机碳红外光谱特征

【目的】研究不同秸秆覆盖量免耕条件下不同剖面深度土壤的红外光谱特征,探讨免耕对土壤有机碳组成的影响及秸秆来源土壤有机碳在不同土层的分布特征。【方法】以吉林省梨树县黑土秸秆覆盖免耕长期定位试验区不同层次土壤为研究对象,对比分析无秸秆覆盖（CK）、33%秸秆覆盖、67%秸秆覆盖、100%秸秆覆盖4种处理土壤红外光谱特征。【结果】连续5年秸秆覆盖免耕种植后的土壤,红外光谱吸光值随着剖面层次的加深而降低;差减土壤矿物光谱后的谱图表明：0—5 cm土层土壤红外基团吸收明显增加,芳香碳、脂肪碳、烷基碳较之下层土壤具有明显的吸收峰。【结论】秸秆覆盖有利于有机碳在表层的累积,显著增加秸秆来源的芳香碳、脂肪碳及烷基碳含量。     

西瓜小拱棚双膜覆盖早熟栽培技术规程

详细介绍了江西省西瓜小拱棚双膜覆盖早熟栽培技术规程,包括早春西瓜育苗技术、西瓜田间管理技术等。     

秸秆覆盖对土壤水盐运动的影响

对不同盐分含量（轻度盐化、中度盐化、重度盐化）的砂壤土进行了秸秆覆盖的模拟试验,结果表明：秸秆覆盖可有效地控制土壤水分的蒸发,从而控制盐分的表聚性,减轻土壤表层的盐化程度,从而达到改良盐渍土的目的。