EVOLUTION AS IT APPEARS TO THE PALEONTOLOGIST

The following facts are those which are put forth through paleontological observation, for verification by others: 1. That many origins of new characters are through some internal action in heredity. 2. That many important adaptive characters arise determinately, definitely, but by extremely slow stages. 3. That degrees of similarity in such origins correspond with degrees of kinship. 4. That degrees of kinship also affect to a certain extent, but not absolutely the time of appearance, or the time of the origin, or the rate of evolution. 5. That such origins find expression not sponta. neously, or irrespective of conditions, or from purely internal mechanical causes, but through some entirely unknown and at present inconceivable relation to ontogeny (habit and use), to environment (external conditions), and to selection. 6. That if such origins do spring from internal hereditary principles, as they appear to do in many eases, slow origins (mutations of de Vries) may be simply due to the same law operating with a different velocity.     

THE 4C APPROACH AS A WAY TO UNDERSTAND SPECIES INTERACTIONS DETERMINING INTERCROPPING PRODUCTIVITY

● The 4C approach considers intercropping performances as the result of joint 4C effects. ● Partial land equivalent ratios indicate which effect(s) are the major one(s). ● A major effect of complementarity is related to a better capture of abiotic resources. Modern agriculture needs to develop transition pathways toward agroecological, resilient and sustainable farming systems. One key pathway for such agroecological intensification is the diversification of cropping systems using intercropping and notably cereal-grain legume mixtures. Such mixtures or intercrops have the potential to increase and stabilize yields and improve cereal grain protein concentration in comparison to sole crops. Species mixtures are complex and the 4C approach is both a pedagogical and scientific way to represent the combination of four joint effects of Competition, Complementarity, Cooperation, and Compensation as processes or effects occurring simultaneously and dynamically between species over the whole cropping cycle. Competition is when plants have fairly similar requirements for abiotic resources in space and time, the result of all processes that occur when one species has a greater ability to use limiting resources (e.g., nutrients, water, space, light) than others. Complementarity is when plants grown together have different requirements for abiotic resources in space, time or form. Cooperation is when the modification of the environment by one species is beneficial to the other(s). Compensation is when the failure of one species is compensated by the other(s) because they differ in their sensitivity to abiotic stress. The 4C approach allows to assess the performance of arable intercropping versus classical sole cropping through understanding the use of abiotic resources.     

马家沟底泥养分分析与肥效作用的研究

通过对马家沟底泥养分分析与水稻的肥效试验结果证明，马家沟底泥及其配制成的底泥颗粒肥料合有一定量的养分，比猪粪养分含量高，具有肥效作用．它不仅能够促进水稻的生长而且还能提高水稻的产量，分别增产４．５５％和１１４．２１％．所得数据可作为施肥的参考，在肥源开发利用上发挥马家沟底泥的肥效作用．