黑龙江省马铃薯气候生产力特征及区划

利用黑龙江省81个气象站1975-2004年30 a的逐日气象资料及相应插值的网格同期逐日气象资料,采用WOFOST作物生长模型,模拟并分析了马铃薯气候生产力的空间分布特征,同时分析了各地气候生产力影响因素及分布特征;利用气候生产力的距平百分率、变异系数及与气候生产力密切相关的有关生育期的4个气候因子(平均气温、气温日较差、日平均日照时数、降水量),采用动态聚类分析方法,将黑龙江省马铃薯可能种植区初步划分为9类气候栽培区,为充分利用当地气候资源发展马铃薯生产提供参考。     

泥石流滩地土地生产潜力评价——以云南小江流域蒋家沟为例

小江流域泥石流滩地水源充足、热量丰富,气候生产潜力(47641kghm-2)较高。本文应用加权指数和法确定了不同类型泥石流滩地(荒滩地、改良滩地和非改良滩地)土壤有效系数f(s)分别为0.405、0.684和0.594;根据生产力阶乘公式计算其气候—土壤生产潜力分别为19295kghm-2、32586kghm-2和28299kghm-2。通过实地调查验证,本文对泥石流滩地生产潜力的估算与现实生产力水平基本吻合,证明本文提出的泥石流滩地土壤有效系数切实可行。     

青海大通退耕还林地林分水分生产力研究

 为了解青海东部黄土高原寒区退耕还林地人工林的水分生产力水平,2001—2003年对青海省大通县退耕还林的人工林进行了群落蒸散测算、标准地生物量调查和解析木分析,并研究了青杨灌木混交林、白桦紫果云杉混交林、华北落叶松纯林、紫果云杉纯林、白桦纯林等11种林分类型退耕还林人工林的林木水分生产力。结果表明:1)3 000株/hm2左右密度的林分是该区较为适宜的造林密度标准;2)在目前的技术经济水平条件下,2 1003333株/hm2密度的青杨灌木混交林成林、白桦纯林、紫果云杉纯林和白桦紫果云杉混交林水分生产效率居所有林分之首,其水分生产力指标可作为该地区常规造林技术条件下乔木成林的水分生产力标准;3)3000株/hm2左右密度的青杨灌木混交林、白桦紫果云杉混交林、紫果云杉纯林和白桦纯林成林的水分生产潜力基本达到了目前当地林木的最大生产能力。表明上述林分类型的造林模式可作为今后退耕还林工程和林业生态工程建设的发展方向。     

Soil compaction and forest floor removal reduced microbial biomass and enzyme activities in a boreal aspen forest soil

Soil enzymes are linked to microbial functions and nutrient cycling in forest ecosystems and are considered sensitive to soil disturbances. We investigated the effects of severe soil compaction and whole-tree harvesting plus forest floor removal (referred to as FFR below, compared with stem-only harvesting) on available N, microbial biomass C (MBC), microbial biomass N (MBN), and microbial biomass P (MBP), and dehydrogenase, protease, and phosphatase activities in the forest floor and 0–10 cm mineral soil in a boreal aspen (Populus tremuloides Michx.) forest soil near Dawson Creek, British Columbia, Canada. In the forest floor, no soil compaction effects were observed for any of the soil microbial or enzyme activity parameters measured. In the mineral soil, compaction reduced available N, MBP, and acid phosphatase by 53, 47, and 48%, respectively, when forest floor was intact, and protease and alkaline phosphatase activities by 28 and 27%, respectively, regardless of FFR. Forest floor removal reduced available P, MBC, MBN, and protease and alkaline phosphatase activities by 38, 46, 49, 25, and 45%, respectively, regardless of soil compaction, and available N, MBP, and acid phosphatase activity by 52, 50, and 39%, respectively, in the noncompacted soil. Neither soil compaction nor FFR affected dehydrogenase activities. Reductions in microbial biomass and protease and phosphatase activities after compaction and FFR likely led to the reduced N and P availabilities in the soil. Our results indicate that microbial biomass and enzyme activities were sensitive to soil compaction and FFR and that such disturbances had negative consequences for forest soil N and P cycling and fertility.     

Energy and water balance measurements for water productivity analysis in irrigated mango trees, Northeast Brazil

Crop water parameters, including actual evapotranspiration, transpiration, soil evaporation, crop coefficients, evaporative fractions, aerodynamic resistances, surface resistances and percolation fluxes were estimated in a commercial mango orchard during two growing seasons in Northeast Brazil. The actual evapotranspiration (E_a) was obtained by the eddy covariance (EC) technique, while for the reference evapotranspiration (E₀); the FAO Penman–Monteith equation was applied. The energy balance closure showed a gap of 12%. For water productivity analysis the E_a was then computed with the Bowen ratio determined from the eddy covariance fluxes. The mean accumulated E_a for the two seasons was 1419 mm year⁻¹, which corresponded to a daily average rate of 3.7 mm day⁻¹. The mean values of the crop coefficients based on evapotranspiration (K_c) and based on transpiration (K_cb) were 0.91 and 0.73, respectively. The single layer K_c was fitted with a degree days function. Twenty percent of evapotranspiration originated from direct soil evaporation. The evaporative fraction was 0.83 on average. The average relative water supply was 1.1, revealing that, in general, irrigation water supply was in good harmony with the crop water requirements. The resulting evapotranspiration deficit was 73–95 mm per season only. The mean aerodynamic resistance (r_a) was 37 s m⁻¹ and the bulk surface resistance (r_s) was 135 s m⁻¹. The mean unit yield was 45 tonne ha⁻¹ being equivalent to a crop water productivity of 3.2 kg m⁻³ when based on E_a with an economic counterpart of US$ 3.27 m⁻³. The drawback of this highly productive use of water resources is an unavoidable percolation flux of approximately 300 mm per growing season that is detrimental to the downstream environment and water users.     

氮密互作对夏玉米物质生产及氮素利用的影响

以夏玉米杂交种郑单958为材料,对不同种植密度和不同施氮水平下夏玉米的物质生产和氮素利用状况进行了研究。结果表明,在中(67 500株/hm2)、高(82 500株/hm2)密度下,氮肥对玉米单株物质生产能力的调控作用更为明显,并主要是通过影响穗粒数来实现的。适量施氮,可促进顶部子粒发育,减少败育,使秃尖缩短、瘪粒数减少,增加穗粒数,增加产量;促进植物体吸收的氮素高效地向籽粒中分配,提高氮肥的利用效率;使玉米叶片维持较高的光合性能,为籽粒形成提供充足的光合碳量,并促进营养体碳氮向子粒运转。     

浅析江西省农田生态系统生产力的稳定性

围绕江西省农田生态系统生产力的主导影响因子,分析和评价了复种指数、耕地资源、气候资源、水资源和施肥等因子对农田生态系统生产力(粮食产量)的影响及其应对的技术措施.     

香叶树人工林生长及生物生产力

通过对福建三明莘口教学林场28年生香叶树人工林生物量与生产力及其生长过程的研究,结果表明:28年生香叶树人工林平均树高、胸径和林分蓄积量分别为16.9m、17.8cm和421.484m3.hm-2,林分生物量和乔木层生物量则分别达310.58和303.67t.hm-2,乔木层生物量所占比例大小顺序为:干(63.47%)>根(17.86%)>枝(14.41%)>叶(4.25%);活枝和叶主要分布在12m以上;与杉木相比,香叶树与同龄杉木生长过程有所不同,前期生长较慢,中期变化强烈,后期较为平稳,成熟龄较长.     

茅台酒有机原料基地耕地的生产能力及持续利用对策

根据茅台酒有机原料基地旱耕地存在的土壤干旱、水土流失与土壤侵蚀、土壤瘠薄等问题,分析了发展有机农业的潜力,提出了加强农田基本建设,强化固土蓄水综合技术,推行保护性耕作技术,发展农耕农艺保持型生态农业,广辟有机肥源,促进地力增加,提高植被覆盖率,进一步改善生态环境等持续利用措施。     

基于 DEA 和 Malmquist 指数的广东省渔业效率研究

【目的】分析掌握广东渔业的产出效率,为发展可持续的低耗高产渔业提供数据参考。【方法】基于数据包络分析（DEA）及 Malmquist 指数,对 2011—2022 年期间广东渔业综合技术效率和全要素生产率指数及其分解进行测算和分析,并与全国平均值进行对比。【结果】广东渔业综合技术效率每年均高于全国平均水平,但2011—2014 年、2018—2019 年和 2021 年广东渔业规模报酬呈现递减。通过对广东水产养殖和水产品捕捞的综合技术效率分别进行测算,发现 2011—2022 年期间广东水产养殖的综合技术效率较高,除 2013 年和 2014 年外,均为DEA 有效。将 DEA 无效年份的广东水产养殖和水产品捕捞在生产前沿面上的投影调整为 DEA 有效,结果显示,2013 年和 2014 年广东水产养殖投入的冗余率分别为 5.98% 和 10.46%,而 2011—2014 年、2018—2019 年和 2021年广东水产品捕捞投入的冗余率在 39.73%~74.27% 之间,说明水产品捕捞的过度投入以及由此引发的捕捞综合技术效率低下是造成 2011—2014 年、2018—2019 年和 2021 年广东渔业规模报酬递减的主要原因。广东渔业的技术进步和全要素生产率上升幅度与全国平均水平相差较远,全要素生产率和技术进步指数均比全国平均增幅低 4.7%,说明广东省在渔业技术进步方面有较大提升空间。【结论】建议广东加大渔业科技的投入力度,加强渔业技术创新,以促进渔业技术进步和提高全要素生产率;加快渔业产业结构调整,合理布局养殖和捕捞规模,以解决广东渔业规模报酬递减的问题;加强渔业资源保护和增殖放流,利用自然生产力增加可捕捞渔业资源;加强水产良种创制及养殖新模式和新技术的开发,进一步拓展水产养殖空间和提高水产养殖的产出效率。