利用气象卫星遥感进行哈尔滨地区作物生长状况监测及产量预报

文章通过对近几年的极轨气象卫星实时接收到的AVHRR/HRPT资料进行处理,数据经校正生成哈尔滨地区归一化植被指数灰度图像,利用种植作物结构不同造成绿度值不同的基本原理,进行作物生长状况监测及产量预报。研究表明,利用气象卫星资料进行作物生长状况监测及产量预报,具有客观、及时和动态跟踪等优点,结合传统气象产量预报方法,使产量预报水平有所提高,准确率可达98%以上。     

1981～2000年中国陆地生态系统NPP时空变化特征分析

利用GLO-PEM模型估算了1981~2000年中国陆地生态系统植被净第一性生产力（NPP）。结果表明：1981~2000年中国总NPP呈现增加趋势,从1981年的2.82 PgC/a增加到2000年的3.13 PgC/a,年均增加0.0155PgC/a,20 a间NPP的平均值为2.98 PgC/a,约占全球NPP总量的4.7%~5.0%。NPP积累主要发生在4~10月,春季、夏季、秋季、冬季NPP量分别占全年总量的15.68%,54.54%,25.50%,4.2%。其中夏季NPP增长最快,占全年NPP增长的64.14%。全国NPP年均值从西北向东南方向呈逐步增加趋势,不同植被类型中,常绿阔叶林年均NPP最高,达745.68 gC/m2,除农业植被外各种植被类型的月均NPP最大值都出现在7月,最小值都出现在1月。经向剖线NPP变化规律不明显。纬向40°N线是南北分界线,往南随着纬度的降低,剖线平均NPP逐渐升高,往北随着纬度的增加,剖线平均NPP逐步变大。纬向剖线NPP均值最高的是20°N线,异质性最高的是30°N线。     

1987年大兴安岭林火碳释放及火后NPP恢复

以大兴安岭地区1985年一类森林资源连续清查资料和1987年林火资料为数据基础,结合GIS技术,进行大兴安岭1987年林火碳释放及火后净初级生产力(NPP,net primary productivity)恢复的研究.通过对1987年火烧迹地林火发生前各树种的生物量的估算,得出在1987年林火中大兴安岭林区森林释放的碳量约为1.97×10~6～2.47×10~6 t;同时分别比较火烧中各树种的碳释放量和不同火烧等级下的碳释放量.结果表明:落叶松在1987年林火中释放碳量约0.96×10~6～1.19×10~6 t,占碳释放总量的49%左右;重度火灾中碳释放量占总碳释放量的99.4%.火后乔木层的NPP恢复在21年间成逐渐增加的趋势,并且恢复趋势表明在火后23～24年的时候中度火灾后的乔木层NPP可达到未过火林地的水平.     

Estimation of spatial and temporal changes in net primary production based on Carnegie Ames Stanford Approach (CASA) model in semi-arid rangelands of SemiromCounty,Iran

Net primary production (NPP) is an indicator of rangeland ecosystem function. This research assessed the potential of the Carnegie Ames Stanford Approach (CASA) model for estimating NPP and its spatial and temporal changes in semi-arid rangelands of Semirom County, Iran. Using CASA model, we estimated the NPP values based on monthly climate data and the normalized difference vegetation index (NDVI) obtained from the MODIS sensor. Regression analysis was then applied to compare the estimated production data with observed production data. The spatial and temporal changes in NPP and light utilization efficiency (LUE) were investigated in different rangeland vegetation types. The standardized precipitation index (SPI) was also calculated at different time scales and the correlation of SPI with NPP changes was determined. The results indicated that the estimated NPP values varied from 0.00 to 74.48 g C/(m²?a). The observed and estimated NPP values had different correlations, depending on rangeland conditions and vegetation types. The highest and lowest correlations were respectively observed in Astragalus spp.-Agropyronspp. rangeland (R²=0.75) with good condition and Gundeliaspp.-Cousiniaspp. rangeland (R²=0.36) with poor and very poor conditions. The maximum and minimum LUE values were found in Astragalus spp.-Agropyronspp. rangeland (0.117 g C/MJ) with good condition and annual grasses-annual forbs rangeland (0.010 g C/MJ), respectively. According to the correlations between SPI and NPP changes, the effects of drought periods on NPP depended on vegetation types and rangeland conditions. Annual plants had the highest drought sensitivity while shrubs exhibited the lowest drought sensitivity. The positive effects of wet periods on NPP were less evident in degraded areas where the destructive effects of drought were more prominent. Therefore, determining vegetation types and rangeland conditions is essential in NPP estimation. The findings of this study confirmed the potential of the CASA for estimating rangeland production. Therefore, the model output maps can be used to evaluate, monitor and optimize rangeland management in semi-arid rangelands of Iran where MODIS NPP products are not available.     

伊犁地区土地覆被变化及其对植被碳储量的影响

以伊犁地区为研究对象，以2005、2010年和2015年的土地覆被类型数据和植被功能型分类方案为依据，并利用植被固碳模型，分析了近10 a伊犁地区土地覆被变化特征及其对植被碳储量的影响。结果表明:1）伊犁地区土地覆被变化主要表现为农业用地、林地和建筑用地呈增加趋势，年变化率分别为0.007%、0.031%和0.001%，草地和灌木呈减少趋势，年变化率分别为0.003%和0.1%。2）10 a增加农业用地的面积为923.9 km²，主要的转化来源为草地，占转化总量的83.9%，同时也有78.8%的农业用地转化为草地。3）由于土地覆被的变化、植被净初级生产力以及不同土地覆被类型之间碳转化系数的影响，导致植被的碳储量总体上减少了2.48×10⁵ t。从整体上来看，伊犁地区的农业用地和草地的变化最为显著，土地覆被的变化导致的植被碳储量整体呈减少的趋势。由此可以得出，近10 a伊犁地区草地和农业用地的变化是影响植被碳储量的重要因素。     

Comparative Assessment of Grassland NPP Dynamics in Response to Climate Change in China,North America,Europe and Australia from 1981 to 2010

Although climate change has been modifying grassland ecosystems for a long time, few studies on grassland ecosystems have focused on large‐scale responses to climate change. Hence, grassland net primary productivity (NPP) from 1981 to 2010, as well as its variations in China, North America, Europe and Australia, was assessed and compared using a synthetic model in this study. Subsequently, the correlations between the NPP of each grassland type and climate factors were evaluated to reveal the responses of grassland eco‐systems to climate change. The results showed that North America, which has the largest area of grassland ecosystems, exhibits maximum grassland NPP of 4225.30 ± 215.43 Tg DW year^?1, whereas Europe, which has the least area of grassland ecosystems among the four regions, exhibits minimum grassland NPP of 928.95 ± 24.68 Tg DW year^?1. Grassland NPP presented an increasing trend in China and Australia, but decreasing in Europe and North America from 1981 to 2010. In addition, grassland NPP is positively correlated with mean annual precipitation, but demonstrates notable differences with mean annual temperature. In conclusion, climate change has a significant role in explaining the spatiotemporal patterns of and the variations in grassland NPP in the four regions.     

三江平原农田生态系统CO_2收支研究

根据土壤异养呼吸速率及农作物生物量对三江平原农田生态系统NEE（Net Ecosystem Exchange）进行估算,农田生态系统包括水田和旱田,分别种植一年一熟的水稻和大豆.结果表明,1 a内农田NEE的季节变化趋势呈“V”形,在植物的非生长季表现为微弱的碳源,水田和旱田NEE分别为0.80和1.12 t·hm^-2;在植物生长季,表现为较强的碳汇,水田和旱田NEE分别为（-6.19±0.21）t·hm^-2和（-3.55±0.22）t·hm^-2.但对土壤有机碳的分析表明,耕作不仅导致土壤有机碳含量减少,而且使土壤有机碳组分中的重组有机碳含量相对富集,使其可利用性降低.因此,农田生态系统在作物生长期间所充当的＂碳汇＂并不能真正增加土壤中有机碳的含量和提高有机碳的质量.     

Effect of Different Ca and P Level on Early Growth of Fast-growth Lines of Wulong Goose

There are many problems in international and do- mestic large-scale production of goose, such as egg- laying ratio, fertility rate and hatchability. Each breeding goose bears few green geese.It is difficult to carry out the chain production of goose. In the early 1980s, Laiyang A gricultural College and its anim al husbandry departm ent system atically selected W ulong Goose. They adopted fam ily selection. Closed -flock breeding, BLUP (B est Linear U nbiased Prediction) and molecule her…     

气候变化对海南岛生态承载力的影响分析

利用植被净第一性生产力估算法测算海南岛自然植被净第一性生产力,并根据海南岛在CO_2倍增情景下气候变化的模拟结果,分析气候变化对海南岛生态承载力的影响。自然植被净第一性生产力与热量和水分条件呈正相关性,气温和降水增幅越大,自然植被净第一性生产力增加越多。而植被净生产力是反映区域生态承载力的间接指标,因此由分析结果知,在CO2倍增情景下,气候变化能显著提高海南岛生态承载力。     

西北地区植被净初级生产力估算模型对比与其生态价值评价

净初级生产力(NPP)是绿色植物在单位时间和单位面积上所能产生的有机干物质总量,是地球碳氧循环研究的关键问题之一。通过使用不同模型进行NPP物质量测算并换算为价值量,分析2000—2009年西北地区NPP价值的时空分异特征,了解西北地区近年植被生态效应的变化格局与趋势。结果表明:(1)CASA模型估算出耕地、草地、常绿针叶林的平均NPP分别为4.15 t.hm 2、4.87 t.hm 2和7.35 t.hm 2,统计模型中综合模型与北京模型和CASA模型估算结果最为相近;(2)研究区NPP价值随时间序列递增,耕地与建设用地的增幅集中在2000—2003年,而草地与未利用地增幅集中于2006—2009年,草地增长最快,2009年达7.91 107万元;(3)以县域为单元分析NPP价值空间差异,空间分布的不对称性、趋向均值的偏离程度有所增加,但高值集聚特征也有所加强;(4)NPP价值的空间集聚变化有低值快速升高、高值继续升高、较高值出现下降3种趋势,青藏高原与黄土高原NPP价值增速最快。NPP价值升高趋势比下降趋势更明显,反映了西北地区生态环境呈现整体好转、局部恶化的态势。