Physical activation of biochar and its meaning for soil fertility and nutrient leaching – a greenhouse experiment

The slow alteration of the surface of charred biomass (biochar) over time may contribute to an improved nutrient retention and thus fertility of tropical soils. Here, we investigated soils from temperate climates and investigated whether a technical steam activation of biochar could accelerate its positive effects on nutrient retention and uptake by plants relative to nonactivated biochar. To this aim, we performed microcosm experiments with sandy or silty soil, mixed with 2.0, 7.5 and 15.0 g/kg soil of fine (<2 mm) or coarse‐sized (2–10 mm) biochar from beech wood (Fagus sp.). After initial fertilizer (NPK), ashes and excess nutrients were leached with water, and the microcosms were planted for 142 days with Italian Ryegrass (Lolium multiflorum ssp. italicum). Thereafter, leachate, soil and plant samples were analysed for their nutrient contents. The results showed that biochar additions of ≤15 g/kg soil left elevated contents of available P and N in the surface soil but reduced their uptake into the plants. As a result, total biomass production was unchanged. Different particle size and application amounts influenced these findings only marginally. Nitrate leaching was enhanced in the sandy soil (+41% for nitrate, but reduced in the silty soil ?17%) and P was immobilized. Hence, the fertility of the temperate soils under study was only marginally affected by pure biochar amendments. Steam activation, however, almost doubled the positive effects of biochars in all instances, thus being an interesting option for future biochar applications.     

Modelling of soil nutrient budgets: an assessment of agricultural sustainability in Nepal

Abstract. Sustaining soil fertility under agricultural intensification and expansion onto marginal lands is a significant challenge in the Nepalese Middle Mountains. In a detailed watershed study it was shown that the overall soil fertility is poor, forest soils display the poorest conditions as a result of biomass removal, and sustaining agriculture is questionable due to the transformation from traditional to multiple cropping systems. Parent material is a significant factor influencing low phosphorus status while insufficient inputs create deficiencies in total carbon, nitrogen and bases. A nutrient budget model was developed to assess inputs, redistribution and losses relative to soil fertility. Yield, input and management data obtained from farm interviews, and soil analysis data were used in the calculation of nutrient budgets. Results from modelling indicate declining soil fertility under rainfed agriculture, forest and rangelands, and marginal conditions under irrigated agriculture subject to intensive cultivation. Nutrient deficits were relatively low for irrigated rice-wheat systems, which benefit from nutrient inputs via sediments and irrigation waters, but the introduction of triple cropping showed greater deficits. Nutrient balances were most critical under rainfed maize production where 94% of the farms were in deficit. Current shortages of organic matter make elimination of nutrient deficits problematic but improvement of composting, biological N-fixation and fertilizer efficiency and reducing erosion were found to be potential options.     

菊花无土栽培技术研究

采用无土栽培技术，对９０余个品种的２６０余盆菊花进行了营养液配方及基质、栽培方式的试验研究，认为在太原市水质及气候条件下，菊花的无土栽培方式以虹吸式、半液式为宜，营养液配方采用３号配方、１号配方或朱士吾提出的通用配方略加调整。     

一品红无土栽培试验

用5种基质和6种不同的营养液,对一品红生长的影响进行了对比试验,结果表明：以蛭石和珍珠岩组成的基质A,搭配Y2和Y3营养液配方的处理效果较佳。     

Yields nutrient intake and soil fertilizing in 40 years fertilizer trials

The set of twenty long‐term field nutrition trials starting from 1957 at five sites. The sites differed by their altitude (from 180 m to 620 m) with average daily temperatures (from 6,8°C m to 9°C m) and soil type (from chernozem to brown podsolic soil) Provided mainly the following results:

? The geonomic division to the fertile sugarbeet region and less fertile potato region did not strictly differentiate the influence of fertilizer and climatic effects to the crop yields.

? The effect of fertilizing was dependent on the nutrient content and on the conditions of releasing and binding of the nutrients in soil.

? The precipitation regime has a strong influence on the effect of the nitrogen escalated doses.

? The facts concerning the nutrient intake are very precious knowledge. These facts have not been examined yet during the long‐term trials.

? The site effect, particularly its climatic conditions, on the nutrient intake is often more obvious compared to the fertilizing effect.

? Very interesting impulses for further research monitoring during the long‐term trials was contributed by “mapping”; of soil capacity to provide nutrients to plants at various sites and under different climate.     

竹林养分循环规律研究：Ⅲ.毛竹纯林竹秆流及其养分输入

在我国毛竹主要产区浙江省安吉县灵峰寺林场试验林的三个区组中，根据立竹直径分布规律确定样竹处理数后，随机布置总共30套秆流收集装置，持续观察21个月，共获91次秆流水。测定每次秆流水量并分析其N、P、K、Ca、Mg含量以研究毛竹林内秆流的变化动态及其养分输入。结果表明：秆流水中不含Ca，其它四元素的年输入量分别为N-1．8557，P-0．0072，K-0.7849，Mg-0.1569，Kg.ha－1；年秆流量为年降水量的12．5％，无论次、月秆流量与相应降水量均为紧密线性相关，但与立竹粗度为显著非线性相关；其它因子，如：立竹所处的坡位、坡向，竹林密度，钩梢强度，立竹分布状况，植株个体表面结构特征等，亦直接或间接地影响着竹秆流的产生和大小。     

阳坡山地花椒园的立地条件和丰产试验

阳坡山地花椒园光热充足,但土壤水分、养分条件较差,因而,限制了单株产量。采用园地覆膜、尿素叶面喷肥技术措施能明显提高单株产量,是石灰岩山地花椒园的重要增产措施。     

水稻光温敏两系不育系15S特征特性及繁殖技术

介绍了水稻光温敏两系不育系15S的形态特征和生育特性,提出了繁殖地点选择,生育期安排,培育壮秧,落地谷的处理等繁殖高产优质不育系种子的技术措施.     

A case-control study to identify farm factors affecting fertility of dairy herds: univariate description of factors

Objective To identify farm factors which were associated with reproductive performance in dairy herds in New South Wales.
Procedure A survey was administered by face to face interview to examine the responses of producers drawn from 757 herds, which used the New South Wales Agriculture Department Dairy Herd Improvement scheme. A case-control approach was used to select a total of 126 herds from the first (top group - cases) and fourth quartiles (low group - controls) for intercalving interval.
Results We found that the estimated interval from calving to first mating was significantly different between groups (P = 0.03) and that the groups significantly differed in both their target for interval to first mating (P = 0.02) and their perceived optimum time for first mating (P = 0.04). Other factors associated with a longer intercalving interval included, use of embryo transfer programs (P = 0.08), younger managers (P = 0.02), fewer breedings per day (P = 0.01), a greater number of people detecting heats (P = 0.07), but less hours spent detecting heats while handling the cows (P = 0.11), and a failure to vaccinate bulls for campylobacteriosis (P = 0.14).
Conclusions Managers of herds with poorer reproductive performance did not intend to mate cattle as soon after calving as managers with better reproductive performance, were not as active in seeking veterinary advice on reproduction, and were attempting to treat reproductive diseases and disorders themselves.