The Wrangell sentinel., 1944-06-30
Garden Help
 ~ By ". R. (Ted) CARTER
SOIL FERTILITY Continued from last week.

From the physical stand point, a soil is composed of particles of min eraI and organic matter which vary in sizes from quite coarse to ex- tremely fine dimensions not visible to the eye. These particles cling to- gether, more or less. and form az gregates. and it is the soil aggre- gates which largely give to the soil it's desirable physical properties. A good state of aggregation, there fore. is the physical soil condition to be provided for most of the com mon garden crops. Other terms sometimes applied to good soil az gregation are good tilth, mellow ness and friableness.
 Good aggregation of soil particles is desirable in a soil because: CD it permits water to soak readily in to the soil to moisten the whole soil mass, and at the same time it al- lows the excess water to drain a. way easily. (2) It allows water containing dissolved plant nutrients plant food-to move freely with in the soil toward the plant roots, where the nutrients can be absorb ed by the plant. (3) It permits the' small plant roots to grow easily through the soil and to contact al greater soil particle surface for. moisture and nutrient absorption. C4) Good soil aggregation permits air to enter the soil readily and, hence, supply oxygen for biological processes and to prevent the soil from becoming stagnant and toxic to plants. (5) Finally, well-aggre- gated soils do not run together, puddle shrink or crack open, thus eliminating many types of root in fries. From this array of benefits to be derived from good soil aggre- gation, one can readily understand it's importance to plant growth in general.
 Not only is a good state of soil aggregation necessary in a soil, but the aggregates should be stable - that is, they should resist the pud- ding effects of continual heavy rains. They should persist under wet soil conditions and the beating of rain on the surface of the soil. Also, the friable soil structure should not be destroyed when the soil dries, which happens without sufficient humus.
 The coarse particles of the soil. sand and coarse organic matter - humus-give the soil bulk and serve as it's framework, and the clay and very fine organic particles act to cement the larger particles together and aggregate the soil. Thus, the clay and fine organic matter parti- cles have an important part in ag- gregation. Too much of either of these materials, however, causes the soil mass to be compact when wet and to shrink and crack when dry, both conditions being detrimental to plant growth. It is important, therefore, in the preparation of soil mixtures to combine the right pro- portions of sand, soil and organic matter to product the proper mix ture for the home garden.
 It should be stressed that no a. mount of fertilizer will make up for poor preparation of the soil or poor physical condition. However, once the soil has been carefully prepared, attention should be turn ed to providing plant nutrient, which is defined as water soluble food contained in the soil. A dozen or more chemical clements are need ed for plant growth, and most soils are lacking in four of these vital foods phosphorus, potash, nitro- gen and calcium.
 All plants need phosphorous to some extent, and some fruit bear ing and Towering ones need a large amount, for phosphorous aids in plants roofing and Towering pro- cesses. To become excessive the phosphorous level is very high, so there is little danger of applying too much, provided the manfuac- turer's recommendations are fol- lowed.
 Potach develops disease resistance by promoting harder growth. Used during dark weather it in creases proper root growth and