This chapter presents a comprehensive update of the research efforts carried out on seaweed products as biologically active compounds for enhancing and conditioning plant growth and plant resistance to pathogens.

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An experiment was carried out to study the effect of soil organic carbon (SOC) and soil texture on the distance of the wetting front, cumulative water infiltration (I), infiltration rate (IR), saturated water conductivity (Ks), and water holding capacity (WHC). Three levels ( 0, 10, 20, and 30 g OC kg-1 ) from organic carbon (OC) were mixed with different soil materials sandy, loam, and clay texture soils. Field capacity (FC) and permanent wilting point (PWP) were estimated. Soil materials were placed in transparent plastic columns(12 cm soil column ), and water infiltration(I) was measured as a function of time, the distance of the wetting front and Ks. Results showed that advance wetting front as a function of time for soil column was 6 minutes and with no differences between OC levels for sandy soils, while it ranged between 90 minutes (0% OC) - 130 minutes (3% OC) for loam soils, and between 470 minutes (0 %OC) and 590 minutes (1%OC) for clay soils, at the same time cumulative water infiltration(I) increases at the beginning of infiltration and decreases with time and levels of OC. The highest infiltration values were in sandy soils, giving data of 0.05 and 0.12 cm min-1, with no significant differences with OC rates. IR values decreased when OC increased in loam soils, and IR increased exponentially in clay soils with increasing OC levels. The values of Ks decrease with increasing OC for sandy and loam soils, and increase when OC increases above 3% for clay soils. FC and WP values were increased for sandy, loam and clay soils when OC was increased. The AW values decreased for both sandy and clay soils compared to loam soils. It can be concluded that AW can be estimated from FC values regardless of texture and OC by the linear function: AW=0.51(FC)+0.005.

Micronutrient deficiency can be considered as one of the yield "quantity and quality" limiting factor in arid calcareous lands and can be considered as the troubling component of hunger. Therefore, enriching food products through adding nutrients to a food product or through increasing soil fertility and breeding crop for nutrient efficiency are alternatives available to improve food quality. However, poor people have no excess to food additives and can benefit from naturally enriched food products or what being called Biofortification. The existence of a general geographical overlap between soil Zn deficiency and human Zn deficiency has been already postulated. As agriculture-based food products are the major source of human nutrition, the relationship between the nutrient status of soils, food crops, and human health is understandable. poor but also deliver all the essential nutrients needed for adequate nutritional health. Sustainable solutions to malnutrition will only be found by closely linking agriculture to nutrition and health. The undergoing review would discuss these concepts and their implementation and uses with special concern on Iraqi conditions.

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