沼肥对水稻增产作用的研究

本文根据本所4年沼肥肥效定位试验结果,证实沼气发酵剩余物是一种缓速兼性的优质有机肥料。不仅沼液、浮渣、沉渣单独施用对水稻有较为显著的增产作用,而且沼液、浮渣、沉渣合并施用对水稻的增产作用更为显著,因此,必须纠正某些地方“弃渣用液”或“弃液用渣”的片面施用沼肥的现象,大力提倡全沼肥的合理施用。     

Harvest residue management and fertilisation effects on soil carbon and nitrogen in a 15-year-old Pinus radiata plantation forest

Growing interest in the use of planted forests for bioenergy production could lead to an increase in the quantities of harvest residues extracted. We analysed the change in C and N stocks in the forest floor (LFH horizon) and C and N concentrations in the mineral soil (to a depth of 0.3 m) between pre-harvest and mid-rotation (stand age 15 years) measurements at a trial site situated in a Pinus radiata plantation forest in the central North Island, New Zealand. The impacts of three harvest residue management treatments: residue plus forest floor removal (FF), residue removal (whole-tree harvesting; WT), and residue retention (stem-only harvesting; SO) were investigated with and without the mean annual application of 190 kg N ha⁻¹ year⁻¹ of urea-N fertiliser (plus minor additions of P, B and Mg). Stocks of C and N in the forest floor were significantly decreased under FF and WT treatments whereas C stocks and mass of the forest floor were significantly increased under the SO treatment over the 15-year period. Averaged across all harvesting treatments, fertilisation prevented the significant declines in mass and C and N stocks of the forest floor which occurred in unfertilised plots. The C:N ratio of the top 0.1 m of mineral soil was significantly increased under the FF treatment corresponding to a significant reduction in N concentration over the period. However, averaged across all harvesting treatments, fertilisation prevented the significant increase in C:N ratio of the top 0.1 m of mineral soil and significantly decreased the C:N ratio of the 0-0.3 m depth range. Results indicate that residue extraction for bioenergy production is likely to reduce C and N stocks in the forest floor through to mid-rotation and possibly beyond unless fertiliser is applied. Forest floors should be retained to avoid adverse impacts on topsoil fertility (i.e., increased C:N ratio). Based on the rate of recovery of the forest floor under the FF treatment, stocks of C and N in the forest floor were projected to reach pre-harvest levels at stand age 18-20. While adverse effects of residue extraction may be mitigated by the application of urea-N fertiliser, it should be noted that, in this experiment, fertiliser was applied at a high rate. Assessment of the sustainability of harvest residue extraction over multiple rotations will require long-term monitoring.     

贵阳地区水稻中甲胺磷农药残留研究

甲胺磷（methamidophos）具有内吸、触杀和胃毒杀作用，防治抗性蚜、蟥和水稻叶蝉、悦虱等药效较好，但残留期较长，有时会影响作物的品质。通过对贵阳地区水稻中甲胺磷农药残留分析，得到贵阳地区的大米中甲胺磷未检出。样品以丙酮提取，经过盐析、再经二氯甲烷萃取后进行气相色谱分析（最低检测浓度为0.03μg/g），本方法的结果符合农药残留分析的要求，因此说明贵阳地区的大米中甲胺磷没有超标，为贵阳地区绿色食品的开发提供理论依据。     

厩肥、秸秆和绿肥的含钾状况及其对土壤和作物钾素的供应能力

以常用有机肥料牛厩肥、猪厩肥、鸡粪及作物秸秆、油菜绿肥为材料，研究了这些有机物的全钾、速效钾和缓效钾的含量状况，以及它们对土壤钾及作物吸钾的供应能力。结果表明：（１）三种有机烘肥及作物秸秆、绿肥中含钾量为０．８５％～４．５０％，其中有３２．７％～６９．７％为速效态钾，１．７％～２５．０％为缓效态钾；（２）肥料与土壤共同培养１５０ｄ后，约有５０％～８０％的速效态钾和缓效态钾仍以两种形态存在于土壤之中     

The effect of lupins as compared with peas and oats on the yield of the subsequent winter barley crop

New high yielding early maturing cultivars of lupins have been introduced in north-west Europe as grain protein crops in crop rotations. This paper reports on a comparative study of lupins with peas and oats, and of their effect on yield of subsequent winter barley crops. These crops were given five levels of N under irrigated and non-irrigated conditions on sand and loam. Under rain fed conditions the grain yield of pea, oat and lupin varied between 24–36, 34–53 and 18–37 hkg DM ha⁻¹, respectively. Supplemental irrigation raised grain yield of oat to 50–60 hkg DM ha⁻¹, while grain yield in pea was not affected and grain yield in lupin in most cases decreased due to gray mould attack and excessive vegetative growth in the indeterminate lupin variety. Under rain fed conditions, the grain nitrogen content of pea, oat and lupin varied between 137–172, 61–80 and 189–226 kg N ha⁻¹, respectively, and was significantly higher in lupin as compared with pea. On sandy soil, similar low-root densities were found for pea, oat and lupin below 30 cm depth. On sand, at final harvest the residual soil-N of lupin and pea, as measured in a subsequent winter barley crop not supplied with N fertilizer, was 15 and 8–10 kg N ha⁻¹ higher than in winter barley following oat, respectively. The nature of the probably more N-root residues of lupin is discussed. On loam, the residual N of lupin and pea was similar, 18–27 kg N ha⁻¹. On sand, under rain fed conditions preceding lupin and pea as compared with oat, increased the barley grain yield at zero N-application 77 and 49%, respectively; the effect of lupin was significantly higher than that of pea until the highest N-level 120 kg N-application ha⁻¹. On loam under rain fed conditions preceding lupin and pea increased the barley grain yield at zero N-application by 36 and 62%, respectively, as compared with oat; at N-application>60 kg N ha⁻¹ the grain yield was similar after all three crops. For both soil types the same level of effect was found under irrigated conditions. Conclusions: Supplemental irrigation might result in lower grain yield in lupin due to gray mould attack and excessive growth if indeterminate lupin varieties are used. Grain nitrogen yield of lupin is significantly higher than that of pea. On sand, the effect of lupin on the subsequent winter barley grain yield is significantly higher than that of pea, probably due to greater N-root nitrogen residues. On loam, lupin and pea have similar effects on the subsequent winter barley crop.     

JMPR 农药残留急性膳食摄入量计算方法

农药残留急性膳食风险评估直到最近才引起大家的关注。目前，粮农组织和世界卫生组织农药残留联席会议（JMPR）研究国际范围农药急性膳食风险评估；美国、英国、荷兰、澳大利亚和新西兰也开始进行国家农药急性膳食风险评估。农药急性膳食风险是急性或短期接触毒性与农药急性膳食摄入量的函数。急性膳食接触量评估常用的方法有：定点或确定性方法和概率模型法。在确定性方法中选取食物的大部分人群消耗量和高残留量来计算膳食摄入量，为了解决混合样品中食品个体之间的残留差异，在计算中引入了变异因子。JMPR根据具体情况分为情形1、情形2a、情形2b、情形3来计算农药急性膳食摄入量。中国应该尽快建立健全膳食结构和农产品性状数据库，建立健全市场中农产品的农药残留数据库，并在高毒和中等毒性农药登记前应采用JMPR的确定性方法，进行急性膳食风险评估，提高农药膳食摄入的安全性。     

糠醛渣生态肥对风沙土理化性质和茄子效益的影响

采用田间试验方法,研究了糠醛渣生态肥对河西内陆灌区风沙土改土培肥效应和茄子效益的影响。结果表明:糠醛渣生态肥原料间的效应是:茄子专用肥糠醛渣5406生物菌肥,糠醛渣生态肥配方比例为:5406生物菌肥0.0103:茄子专用肥0.1291:糠醛渣0.8606。施用糠醛渣生态肥与传统化肥比较,风沙土体积质量、pH、EC和可溶性盐分别降低了13.85%、1.07%、6.22%和6.92%;Hg、Cd、Cr和Pb离子分别降低了21.21%、40.00%、18.70%和21.94%;总孔隙度、团聚体和饱和持水量分别增加了13.35%、16.98%和13.35%;CEC、有机质、碱解氮、速效磷、速效钾、有效锌和有效钼分别增加了19.20%、25.93%、0.29%、1.89%、0.17%、2.08%和8.33%;真菌、细菌和放线菌分别增加了59.00%、41.94%和24.32%;蔗糖酶、脲酶和磷酸酶分别增加了57.51%、5.88%和10.35%;茄子单果重、单株果重、产量和施肥利润分别增加了5.27%、5.35%、3.01%和0.51×104元/hm~2。糠醛渣生态肥施用量与风沙土总孔隙度、团聚体、饱和持水量、有机质、速效养分和茄子产量呈显著的正相关关系;与体积质量、pH呈显著的负相关关系;糠醛渣生态肥施用量与茄子产量间的线性回归方程为y=51.2300+1.5151x–0.0408x2,经济效益最佳施用量为17.40 t/hm~2,茄子理论产量为65.24 t/hm~2。在风沙土上施用糠醛渣生态肥,有效的改善了土壤理化性质和生物学性质,提高了土壤有机质和番茄产量。     

模拟池塘中锶-89的迁移和积累动力学

采用放射性同位素示踪技术研究了核污染关键核素之一——~(89)Sr在水生生态系中的动力学行为。当示踪剂~(89)Sr一次性引入水系后,即向系统内的动植物及底泥迁移,从而使系统各组分中~(89)Sr-Sr的量均随时间变化。结果表明:1.在试验期间,池水中~(89)Sr-Sr的含量随时间减少,6d后由原来的1.76 ppm降至1.01ppm,11d后已不到原来的一半,第35d时只及原始量的30％。2.池水中的~(89)Sr-Sr向系统各组分中的迁移速率和数量因组分的性质而异。比如底泥,1d后由原始的0增加到7.07 ppm,11d后趋向平衡,以后几乎不再增加;~(89)Sr-Sr在鱼和螺蛳体内的含量在试验期间均随时间增加,35d时分别由原始的0增加到18.73ppm和48.28ppm;在处理当天,金鱼藻中~(89)Sr-Sr虽增加较快,由原始的0增至6.68 ppm,但4h后却几乎不再增加。3.水生动植物对放射性锶都有一定的浓集作用,最大的浓集系数分别为:螺蛳94.7,鱼36.7,金鱼藻只有12.6。可见,贝壳类动物对水系中的放射性锶有较强的去污能力。     

Growth and phosphorus uptake of maize cultivated alone,in mixed culture with other crops or after incorporation of their residues

Intercropping or rotating of P‐efficient crop species which mobilize sparingly soluble P by their root exudates can have beneficial effects on growth and P uptake of P‐inefficient species. We aimed at studying the effect of intercropping or incorporating of crop residues of P‐efficient crops on the components of maize P‐uptake, i.e. the root‐system size and P influx (P‐uptake rate per unit root length). This was studied in 3 pot experiments in a low‐P sandy soil. In the first experiment, maize was intercropped with white lupine, sugar beet or oilseed rape, and with groundnut in the second experiment. In the third experiment, maize was grown after incorporating the crop residues of white lupine, sugar beet or oilseed rape. Maize growth and yield was strongly inhibited when intercropped with white lupine, sugar beet or oilseed rape, probably because of competition for nutrients. But with groundnut as the accompanying species, maize yield was increased by a factor of 3, mainly because of an enhanced P influx. Crop residues of oilseed rape and sugar beet increased the yield of maize by factors 2 and 1.6, respectively, because of a 3 and 2 times higher P uptake as compared to maize grown after maize without incorporation of crop residue. The reason for the higher maize P‐uptake after oilseed rape was an 11 times higher P influx as compared to maize without crop residues, and after sugar beet residues because of an enhanced root growth and a 4 times higher P influx. Lupine residues did not improve maize growth, mainly because of a low P influx, which was even less than that of maize grown without crop residues. The soil solution P concentration and calcium acetate lactate‐extractable P (CAL P) measured in this study did not reflect the P availability as indicated by the plants (P uptake, P influx). This indicates that other mechanisms such as P mobilization in the rhizosphere by root exudates or cell‐wall components were responsible for the increased P availability. These mechanisms need further investigation.     

Can conservation tillage and residue management enhance energy use efficiency and sustainability of rice-pea system in the Eastern Himalayas?

ABSTRACT

Low productivity and energy use efficiency (EUE) of rice farming are the major concerns for agricultural sustainability in the Eastern Himalayan region of India. A field experiment on rice (Oryza sativa L.)-pea (Pisum sativum L) system was conducted for three consecutive years during 2012–15 in lowland ecosystem to assess the direct and residual impact of tillage and residue management (RM) practises on productivity and sustainability. Significantly higher grain yield of rice was achieved under no-till (NT) than minimum tillage (MT) and conventional tillage (CT). Among RM practises, 50% NPK + green leaf manure, 50% NPK + weed biomass and 50% NPK + in-situ residue retention recorded significantly higher mean grain yields than application of 50% NPK and 100% NPK without residues. Residual effect of MT in preceding rice gave significantly higher green pod yield of succeeding pea than NT and CT. The system EUE was significantly higher under MT (rice)-NT (pea) compared to those of NT-NT and CT-NT systems. The sustainable yield index of rice and pea was maximum under MT-NT followed by NT-NT. Thus, NT/MT with suitable RM practises is a pertinent strategy for sustainable productivity of rice-pea system in the Eastern Himalayas and in similar adjoining regions.