长期地膜覆盖与施肥对土壤磷素和玉米吸磷量的影响

利用比较法对长期连续覆膜(17年)后土壤磷素的变化以及玉米吸收量的变化进行了研究。结果表明:经过17年的耕作,无论是施有机肥还是磷肥均能显著增加土壤中速效磷以及全磷的含量;覆膜栽培与裸地栽培比较结果,覆膜对于土壤中速效磷以及全磷含量的变化影响不大;对植株的籽粒、轴、叶片、茎的全磷进行了测定后显示:覆膜可以促进籽粒、轴、茎对磷的吸收,抑制了叶片对磷养分的吸收;从成熟期地上部分累积磷的总量来看,覆膜可以明显提高作物对磷的吸收。     

干旱荒漠区不同覆盖对酿酒葡萄园土壤的综合效应研究

针对甘肃河西地区大面积栽培酿酒葡萄而水资源短缺的现状,试验研究了地面覆膜、覆麦秸、覆麦壳等节水措施对干旱荒漠地区酿酒葡萄园土壤水分、温度和肥力等因子的效应,结果表明,几种节水措施均有明显增温效应,提高土壤含水量。覆草效果优于覆膜。覆麦秸和麦壳表现前期降温,后期增温保温的双重效应,并增加了土壤有机质及速效N、P、K含量,其中土壤有机质含量增加17.36%~18.51%,全氮增加7.35%~8.82%,速效磷增加8.51%~9.96%,速效钾增加47.5%~53.9%,土壤容重降低0.19gcm-3~0.20g cm-3,可溶性固形物含量提高0.5%~1.7%,产量提高3722.5~4162.5kg hm-2。     

覆盖模式对连作烟田青枯病防治的影响

为了探索防治烟草青枯病的农艺栽培措施,于2008和2009年通过田间小区试验考察了地膜覆盖、水稻秸秆覆盖及黑麦草等覆盖对连作烟草青枯病的防治效果,并分析了不同覆盖模式对土壤青枯菌,土壤可培养细菌、真菌和放线菌种类及数量的影响.结果表明:膜草覆盖和前膜后秸覆盖均能有效防治烟草青枯病,在移栽后4周和采收末期的防效均达到65％以上,单一黑麦草覆盖或单一秸秆覆盖的防效仅为32％～62％;不同覆盖模式对土壤微生态的影响效果不同,盖膜和种植黑麦草处理,其移栽后1周、4周的相对抑菌率均达75％以上,前膜后秸在栽后1周、4周的相对抑菌率均达到74％以上;膜草覆盖和前膜后秸均能增加土壤可培养细菌的种类,但对真菌和放线菌的种类影响不大,因此,膜草覆盖和前膜后秸两种覆盖模式在防治青枯病方面具有较高的实用价值.     

Effects of soil conservation measures in a partially vegetated area after forest fires

After forest fires on the east coast of Korea in 2000, some burnt areas were left untreated. Although 80% of the area was reasonably revegetated within 3 months, about 20% of the area was partially vegetated, mainly due to a low density of sprouters and poor growing conditions (eroded soil and steep slopes). Three years after the fires, the effect of soil conservation measures, such as mulching with wood chips, seeding with native plant species and log erosion barriers (LEBs), on runoff and soil erosion were examined using runoff plots. Wood chip mulching greatly reduced runoff and sediment yields and these effects were consistent regardless of the volume of rainfall. Neither seeding nor LEBs reduced runoff and sediment yields. No positive or negative effects of mulching, seeding or LEBs on ground vegetation cover were observed. The ineffectiveness of seeding and LEBs may have been due to the steep slope, the failure of germination and establishment of seeded plants, and the small diameter of logs. Treating hill slopes with mulch should be considered where post-fire regeneration is slow and there is an absence of organic material such as litter.     

我国农用地膜应用现状及展望

本文综述了我国地膜的使用种类、应用情况,并就我国目前的地膜污染现状提出地膜标准化生产及回收的途径,并提出研发全生物降解地膜解决农田＂白色污染＂的对策。     

降解地膜对不同作物应用试验

通过光降解地膜与普通地膜对不同作物生长情况影响的对比应用试验,揭示了光降解地膜在减少土壤残膜污染的同时,与普通地膜具有相同的提高地温、保墒、增加产量、提高效益等作用。     

Influence of dry season supplementation for cattle on soil fertility and millet (Pennisetum glaucum L.) yield in a mixed crop/livestock production system of the Sahel

An experiment was conducted in 1996 and 1997 in semi-arid Niger, to determine the influence of supplementation (no supplement, supplemented with millet bran + simple superphosphate + blood meal) of cattle and mulching (0 or 3 t ha⁻¹ of Aristida sieberiana straw) on soil fertility and millet yield. Manure was applied through corralling at a rate of 3 t faecal dry matter (FDM) ha⁻¹ alone or associated to mulching. The residual effects of the treatments were measured on a second millet crop in 1997. Compared to control, the association of mulching and corralling of supplemented as well as non supplemented cattle increased soil pH (KCl) (P < 0.01), Bray1-P (P < 0.05) and NH₄-N (P < 0.05); grain by 136% (P < 0.01) stover yeild by moer than 150% (P < 0.05); and N and P uptake (P < 0.01) during the two cropping seasons. The association of mulching and corralling increased soil NH₄-N (P < 0.01) and soil pH (P < 0.01), compared to the sole corralling. The improvement of soil chemical properties resulted in grain yield increases of 54% (P < 0.01) and stover increases of 42% (P < 0.01). The effect of mulching and corralling association on grain and stover yeilds was higher when cattle were supplemented (67 and 50%) than when they were not supplemented (30 and 26%). The effects of the supplementation on grain and stover yields, and N and P uptake by millet, were restricted, when animals were corralled on bare soil (no mulching). The residual effects of supplementation were minimal. This revised version was published online in November 2006 with corrections to the Cover Date.     

Nutrient recycling potential of Tephrosia candida in cropping systems of southeastern Nigeria

Improving fallow quality in cassava–fallow rotations in southeastern Nigeria through the use of leguminous cover crops has been shown to sustain the productivity of such systems. We studied the effects of age (1 or 2 years) of Tephrosia candida fallow on biomass and nutrient accumulation, on weed biomass and yield response of cassava/maize intercrop and on changes in soil chemical properties in a 3 yr field trial. Results were compared with those obtained in natural fallow. Total biomass and litter were three times higher in plots fallowed for 2 yr with Tephrosia candida than in those under natural fallow for the same period. Weed biomass was 205% lower in T. candida plots fallowed for 2 yr than in the natural fallow and was 174% smaller in T. candida plots fallow for 1 yr than in the natural fallow. Nutrient (nitrogen, phosphorus, calcium, magnesium and potassium) yields in leaves of T. candida fallow for 2 yr were on average 200–300% higher than in leaves of other fallows. The same trend was observed for cassava and maize yields. Soil chemical changes at soil depth 0 to 5 cm showed significant increases in N and C concentrations after 2 yr fallowing and a year of cropping, particularly in the planted fallow plots. Conversely, soil pH, available P and the exchangeable cations, especially Ca were lower, while Al was higher than the initial values, mainly in plots fallowed under T. candida, indicating a tendency of this fallow species to further exacerbate the soil acidification problem of the acid Ultisol at the study site in southeastern Nigeria.     

Influence of soil moisture content on soil solarization efficiency

Soil temperature under plastic cover is a function of incoming radiation and thermal characteristics of the mulching material and the soil. A field experiment was conducted at Fudhiliyah Agrometeorological research station to investigate how soil temperature is influenced by different soil moisture content regimes during soil solarization. Two soils, sandy loam and silty clay loam, were brought to five volumetric moisture regimes (M1–M5). The moistened soils were mulched with 180-μm-thick transparent polyethylene. Measurements of hourly soil temperatures for depths of 0.00, 0.05, 0.10 and 0.30 m were recorded from 1 June to 30 September. The results showed that the maximum soil temperatures decreased with increasing soil moisture content. The relationship between the hourly rise in soil temperature and heat flux were significantly affected by soil moisture content. Moreover, soil solarization efficiency decreased with increasing moisture content. The higher temperatures in both soils under the M4 irrigation regime resulted in faster eradication of the pathogenic fungus, Fusarium oxysporum (sp. lycopersici).     

麦秸覆盖冬小麦节水增产效果分析

麦秸覆盖麦田技术措施能有效地减少田间蒸发，提高水资源利用率。试验得出：旱地增产14％，水地增产7％－13％，旱地节水9．45％，水地节水5％－7％，节水主要在前期。同时麦秸覆盖保温能防止麦田冻害，提高土壤肥力，增加亩穗数，提高成穗率。