MULCH (more correctly mulsh, probably from AS. mohle, earth mold; ultimately connected with Goth. molar, Lith. ma/ti, Lat. mo/cre, to grind, Eng. meal). A covering of loose mate rial such as brush, leaves. manure, straw, or earth, maintained on the surface of the soil main ly for the purpose of preventing evaporation, 'which it accomplishes by breaking the continuity of the capillarity in the soil and thus retarding the rise of water to the surface. Stirring the surface soil, and thus maintaining what is termed a 'soil muleh,' brings about the same result. The use of the mulch of vegetable matter is prob ably not so common as formerly. but the soil 111111(.11 is increasing in favor. and in arid regions where agriculture is dependent upon irrigation and conservation of moisture is a matter of great importance. In addition to chocking evaporation, mulehes of vegetable matter are useful in pro tecting the surface soil from and wash Mg, keeping the soil cool. preventing freezing, and retarding growth in the spring. lAfolehing is a valuable means of reclaiming washed or 'galled' lands, and for securing a growth on dry, bare spots in lawns and meadow-. _\ mulch of barn yard manure nut only conserves moisture, but turnisl aCCel?tabl' Plant Itilching berry bushes, orchard trees. etc.. on a large scale with coarse manure and refuse material is not to be recommended, because it intcrieres with cultivation. harbor, and cause, the plant, to remain near the sur faee, thus increasing the danger of injury by drought. Such mulches. except on a small scale and fur speeial such as protecting small from injury by late frosts by retarding growth in spring. should he replaced by thorough stirring of the soil to maintain a soil mulch.
The depth and character of this soil mulch must be determined by a variety of conditions, among hielt art' the kind and root habits of the plant and the character of the soil and climate. It is evident that any crop. such corn, with an eXtell-iVe surface root -ystein, would be injured by the destruction of its roots if stirring ‘vere frequent and deep. Again, in arid regions the mulch must be deeper and more perfect than in regions of frequent rainfall, in order be effec tive and useful.
MULDER, .1011ANNEg (1S113-50). Dutch chemist, born at ttrecht.
After obtaining the degree of doctor of medicine at the university of his native town in 1425, he commenced the practice of his at Amsterdam, but was soon invited to teach botany and subsequently chemistry al the medical school at Rotterdam. In IS-10 he Was elected professor of chemistry at the t'iliversity of 1. trecht. and kept this post until 1S68. when lie retired from active service. Molder is best known for his re searelics on the prot•eids. Concerning the ehemi cal nature of these substances. he advanced a theory according to which the protpids contain in common a eharacteristie ingredient which he named prole in. The theory led him into a con troversy with Liebig and was not accepted. lie is the allthor of excellent works on and agricultural chemistry, on the chemistry of wine and beer, on diet and nutri tion, etc. II is l'Itcmistry of I table rind ?nal l'h yxinlogy has been translated into English by Fromberg, and his ('lit mist ry of win, by L'tnr•e .fonts. lie also an autobiography antler the title tr,er,as.c.clicis (published posthu mously in IS'?1: 241 ed. Iss31.