中国小麦土壤速效钾丰缺指标与适宜施钾量研究

系统总结我国开展的小麦土壤速效钾丰缺指标与适宜施钾量研究,结果表明:30a来我国小麦土壤速效钾丰缺指标明显提高;不同区域之间小麦土壤速效钾丰缺指标差异颇大,以缺钾处理相对产量90%指标为例,土壤NH4OAc-K含量变动于80～246 mg/kg;除黄淮海平原、四川盆地、关中灌区和河套灌区外,我国小麦土壤速效钾丰缺指标研究存在很多空白区域;小麦土壤缺钾较为普遍,第2～4级为土壤速效钾集中分布的丰缺级别,缺钾处理相对产量大多处在70%～100%;土壤养分丰缺指标研究的试验点数不宜过少,丰缺指标高端和低端采用外推数据需谨慎,并应予以注明;适宜施钾量与土壤速效钾丰缺级别线性负相关,与小麦目标产量线性正相关,与钾肥当季利用率线性负相关;当钾肥当季利用率50%、目标产量3.0～12 t/hm2时,土壤速效钾丰缺级别第1～7级的小麦适宜施钾量范围依次为0、17～67、34～134、50～202、67～269、84～336和101～403 kg/hm2。     

云南省生物质能商业模式发展研究——以昆明市为例

通过分析云南省生物质能源利用及相关企业情况,以昆明市为例,对生物质能源综合利用商业模式发展进行研究。结果表明:云南省生物质资源丰富,但利用率较低,生物质能源利用企业较多,但分布较为零散,未形成规模与产业链,且本土企业较少;发展生物质能源综合利用的商业模式,要利用公式确定资源可利用量,考虑该地区的实际情况,并选择适合的模式进行发展。在此基础上,提出因地制宜建设产业基地;做好秸秆资源的收集、转运、储存;对产业进行整体规划,形成产业链,加强相关部门的协调;加大资金与科技的投入,提高技术水平,探索生物质能源综合利用新途径等商业模式发展建议。     

铲草施肥对降香黄檀与檀香混交林土壤速效养分的影响

【目的】探讨土壤速效养分对不同抚育措施的响应以及季节变化,以期选择出可以有效改善林地土壤养分状况的抚育措施,为降香黄檀Dalbergia odorifera与檀香Santalum album混交人工林抚育体系的建立提供参考。【方法】以珍贵树种降香黄檀与檀香混交林下表层土壤为试验对象,设置4个处理,即对照(CK)、铲草、施肥、铲草+施肥(铲+施),每处理4次重复,测定土壤速效养分和pH的变化,每季度测定1次。【结果】铲草施肥处理后土壤pH无显著变化,但增强了土壤酸碱缓冲性能,减缓土壤pH的季节性波动;土壤速效养分含量受季节和抚育措施变化影响显著,各处理的铵态氮和硝态氮含量均在秋、冬季节出现峰值;铲草、施肥和铲+施处理的全年土壤铵态氮含量较CK分别增加16.87%、8.17%和20.25%;铲草和铲+施处理的土壤硝态氮含量较CK分别增加12.69%和21.45%,施肥处理较CK减少1.81%;铲+施和施肥处理的土壤有效磷含量较CK分别增加50.63%和19.58%,铲草处理较CK减少2.53%;铲草、施肥和铲+施处理的土壤速效钾含量较CK分别增加117.18%、57.91%和142.54%。【结论】土壤速效养分含量对铲草施肥抚育措施出现的响应不同,但铲草施肥各措施都促进了土壤中一种或多种速效养分含量的增加,铲+施处理促进了林下土壤速效养分含量的全面增加,对于降香黄檀与檀香混交林来说铲+施处理是一种较为理想的抚育措施,对其生长有较好的促进作用。     

Effects of Green Manures and Zinc Fertilizer Sources on DTPA-Extractable Zinc in Soil and Zinc Content in Basmati Rice Plants at Different Growth Stages

Rice is very sensitive to low zinc(Zn) supply in submerged paddy soils and Zn deficiency is one of the major limiting factors in determining rice production in India. A field experiment was conducted during the summer-rainy seasons of 2009 and 2010 at the research farm of the Indian Agricultural Research Institute, New Delhi, to determine the effects of summer green manure crops and Zn fertilizers on diethylenetriaminepentaacetic acid(DTPA)-extractable(available) Zn concentration in soil and total Zn content in Basmati rice cultivar Pusa Basmati 1 at periodic intervals. Summer green manure crops included Sesbania aculeata(Dhaincha),Crotalaria juncea(Sunhemp), and Vigna unguiculata(Cowpea) and the Zn fertilizers used were ethylenediaminetetraacetic acid(EDTA)-chelated Zn, ZnSO_4·7H_2O, ZnSO_4·H_2O, ZnO, and ZnSO_4·7H_2O + ZnO. Beneficial effects of summer green manure crops and Zn fertilizers on DTPA-extractable Zn concentration in soil and total Zn content in dry matter of Basmati rice at periodic intervals were observed, with significant increases in all the determined parameters, in comparison with those in the control(no Zn application or summer fallow). The rate of increase varied among summer green manure crops and Zn fertilizers during both years. Among the summer green manures, incorporation of S. aculeata led to a significant increase in mean Zn content in Basmati rice grain and straw when compared with C. juncea, V. unguiculata, and summer fallow treatments. Among the Zn fertilizers, significant increases in Zn content in Basmati rice dry matter and DTPA-extractable Zn concentration in soil during various growth stages of the plant were recorded with EDTA-chelated Zn application, followed by the application of ZnSO_4·7H_2O, ZnSO_4·H_2O, ZnSO_4·7H_2O + ZnO, ZnO,and no Zn. The highest mean Zn content in Basmati rice grain and straw was recorded with EDTA-chelated Zn application in 2009 and 2010, respectively. The application of ZnSO_4·7H_2O was the second best treatment after EDTA-chelated Zn; however, it was statistically inferior to EDTA-chelated Zn. The lowest values were recorded with the control(no Zn application) during both years of study. The amount of Zn concentration in soil was found to be significantly positively correlated with the Zn content in Basmati rice dry matter during both years. Significantly higher levels of residual fertility in soil after the harvest of Basmati rice were observed with application of EDTA-chelated Zn and incorporation of S. aculeata when compared with those of other Zn sources and summer green manures.     

辽宁省耕地质量演变趋势研究

在辽宁省主要土样类型建立43个耕地质量监测点,采集86个土壤样品,对耕层厚度、容重、有机质、土壤pH、全氮、有效磷、速效钾等7项监测指标进行监测分析。结果表明:辽宁省耕层厚度和容重变化不大,土壤pH值和全氮含量基本稳定,有机质、有效磷和速效钾含量有所提高;化肥使用率有所降低,有机肥投入有所增加。     

成都平原西部土壤速效钾含量剖面分布特征及其影响因素

为了准确获取土壤钾素剖面分布信息,掌握区域钾素运移和合理精准施肥的需要,基于134个剖面(0—100 cm)采样数据,运用经典统计学和地统计学方法探讨了成都平原西部土壤速效钾剖面分布特征,并对比分析了成土母质、土壤类型和土地利用方式对土壤速效钾剖面分布的影响。结果表明:土壤速效钾含量在水平方向上具有一定的规律性,其高值密集在金马河以南的崇州、邛崃和大邑区域,而低值出现在都江堰—郫县—温江一带,低值区面积占研究区面积50%以上,总体呈现由西南部向东北部显著降低趋势。垂直方向上0—100 cm随土层逐渐降低,表层土壤显著高于下层土壤(P0.05),下层土壤变幅(最大值与最小值之差)随土壤深度的增加逐渐减小。0—100 cm不同土层块金系数均为25%～75%,表现为中等程度空间自相关性,受结构性因素和随机因素共同影响。表层土壤速效钾空间分布受成土母质、土壤类型和土地利用方式共同影响,土壤类型的解释能力最高,分别是成土母质和土地利用方式的1.97,2.58倍;下层土壤主要受成土母质和土地利用方式的影响,影响程度均随着土层深度的增加而增加,相较之下,母质的影响程度增加更为显著。总体来看,成土母质和土地利用方式是影响研究区土壤速效钾剖面分布的主控因素。     

Citric acid extraction—An underestimated method in forest nutrition?

Since recent studies reveal citric acid to be favorable for estimating plant‐available P in soils, we investigated if it can also be used for assessing other nutrients. According to our results, it provides stronger correlations with the tree nutrition for Mg (beech, spruce), Ca+K (beech) and Fe (spruce) than the standard methods for determining exchangeable cations. Thus, when estimating plant‐available P by citric acid‐extraction, these cations should be additionally measured in ICP analysis.     

施肥对青藏高原燕麦种子生产的增产效应

通过研究施肥水平对燕麦Avena sativa种子产量和品质的影响,筛选出适宜燕麦种子高产的施肥量,为提高燕麦种子生产能力提供直接的理论依据.研究结果表明:在试验设计的施氮梯度范围,施氮对燕麦产量和品质影响作用明显,施氮水平与种子蛋白质含量之间呈显著的线性回归关系(R=0.896 8,P＜0.01),随着施肥量的增加,蛋白质含量持续增加;而施氮水平与有效分蘖数、小穗数、草产量和种子产量之间呈显著的二次回归关系(P＜0.01),表现为"低-高-低"的变化趋势,施氮60 kg/hm2时燕麦种子产量为4358.5 kg/hm2,达到最高,施肥量继续增加,种子产量增幅下降,投入产出比降低.因此,从高产和高效角度综合考虑,生产中以收获燕麦种子为目的时,施氮量应选择60 kg/hm2,而以生产饲草为目的时,施氮量应选择75 kg/hm2.     

玉米秸秆不同部位营养成分、体外消化率和有效能的比较

为了高效利用玉米秸秆各部位,采用近红外漫反射光谱法,以整株玉米秸秆作为对照,对玉米秸秆不同部位(茎髓、茎皮、苞叶和叶片)的营养成分,干物质(DM)和中性洗涤纤维(NDF) 30、48 h体外消化率、有效能和吨干物质产奶量等进行了测定。结果显示:粗脂肪、粗蛋白在叶片中含量最高,茎皮中最低;苞叶中的淀粉、总可消化养分和非纤维性碳水化合物含量最高;茎皮中的酸性洗涤纤维、木质素的含量最高,苞叶和叶片中含量较低;苞叶的DM (48 h)和NDF (30,48 h)的体外消化率最高,显著高于叶片、茎髓、整株秸秆、茎皮(P<0. 05);苞叶的有效能和吨干物质产奶量显著高于其叶片(P<0. 05),叶片显著高于茎髓、整株秸秆、茎皮(P<0. 05)。综合以上指标比较,玉米秸秆各部位的综合营养价值存在差异,从高到低的顺序为苞叶>叶片>茎髓>整株秸秆>茎皮。