Combined Irrigation and Fertilization in Arid Zones

Abstract

Sand dunes and highly calcareous soils occupy vast areas in arid zones. The soils are characterized by low available nutrient content and low to medium water-holding capacity of the upper soil surface. These features result in low vegetation density under arid climate conditions. The introduction of trickle irrigation coupled with liquid fertilizers turned desert sand dunes and highly calcareous soils into productive agricultural soils for high cash crops. The intensity of daily nutrient supply dictates the farmer's consideration of the form of nitrogen supplied to the crop and to the variable sensitivity of plants to the different forms of N supplied by various fertilizers through the irrigation system. The combination of high root temperature and high ammonium concentration is of particular importance. Plants that have relatively low carbohydrate content in their roots might suffer from ammonia toxicity if a high daily supply of ammonium is available. High concentrations of urea and very high calcium carbonate content in the soil are also dangerous to ammonium- sensitive plants like tomatoes. Planning the irrigation system and nutrient supply to the crops according to their physiological stage of development, and consideration of the soil and climate characteristics, can give high yields and high quality crops with minimum pollution, but salt accumulation on the soil surface should be prevented, either by sprinkle irrigation, or by plastic mulch during the growing season.

Growth, transpiration, root‐born cytokinins and gibberellins, and nutrient compositional changes in sesame exposed to low root‐zone temperature under different ratios of nitrate: Ammonium supply

“…Root-zone temperatures affect the uptake of different N forms (Marschner, 1986;Kafkafi, 1994). Comparative studies on nitrate and ammonium nutrition of plants suggested that nitrate uptake and transport to the shoot is limited more than that of ammonium by low root temperatures (Clarkson and Warner, 1979;GanmoreNeumann and Kafkafi, 1980).…”

Evaluation of Phosphorus Sources and Rates on The Yield and Quality of Fertigated Potato Grown in Sandy Soil

“…Phosphorus has various effects on tuber quality, such as tuber size and percentage of dry matter (indicated by specific gravity) of the tuber (Freeman et al, 1998 andRosen et al, 2014). Kafkafi (1994) considered fertigation as an efficient method for providing and supplying available forms of immobile elements such as P, at a desirable level in root zone. Also successful P-fertigation has been reported by Papadopoulos, (2000).…”