Soil Study

More Efficient Water Management in Rice Crops The aim of the study was to quantify the water used in two different systems of rice crop, water-seeded system and dry-seeded system, during the first month of crop growth. This research was carried out in California (USA) along with the Universidad Politécnica de Madrid (UPM) and 15 researchers from other universities and research centers of Italy, China, Egypt and United States. Results suggest that these two systems of water management show no differences regarding the total crop cycle. Rice is the third-largest global crop area (165m hectares) after wheat and corn, but it is the most important crop worldwide considering the large area and the amount of people who depend on their harvest. Globally, the cultivated area in China and India represents half of the total surface. Spain has the second largest rice area of the European Union with 115,000 hectares behind Italy. Rice crops usually grow under conditions of continuously...

Silicon 'Plant Stones' for Strong Rice Silicon quite literally pumps up the strength of a rice plant. Rice takes up Si with the soil solution and forms amorphous Si dioxide bodies within the plant tissue, the so-called phytoliths (literally translated "plant stones"). These phytoliths make the plant stem and leaves stronger and more rigid. Thus, a sufficient Si supply enhances the plants' resistance against heavy rain and wind and against attacks of pests and fungi. Undoubtedly, an indispensable element for sustainable rice production, the processes which control Si availability in the soil remain rather understudied. In their paper Anika Marxen from the Helmholtz Centre for Environmental Research -- UFZ and her team study rice soils in Vietnam in order to understand these processes, providing scientific base for future recommendations for sustainable rice production. Silicon is contained in most soil minerals and mineral weathering slowly rel...

Green Manuring A growing crop that is plowed under and mixed with soil to enrich the organic matter is called green manure crop. The practice of plowing under or soil incorporation of such green manure is called green manuring. Green manures are mostly leguminous crops which are high in nitrogen contents. Generally following crops are suitable for green manuring: Jantar, Guara, Cow peas, Alfalfa, Sun hemp and Clover etc. Criteria for the selection of green manure crops It should be fast growing and easily established. It should produce abundant and succulent biomass. It should be well adapted to the local conditions. Growth habit of crop should encourage ground cover soon after its establishment. It should be able to fix nitrogen in the soil. It should have a wide climatic and soil adaptation and ability to grow on poor soil. Advantages Improves the soil fertility Adds nutrients and organic matter to the soil Improves the soil structure Improves soil aer...

Difference between Biennial and Perennial Plants Biennial plant completes its life cycle in two growing seasons. The first season’s growth is entirely vegetative, and is typically characterized by short, low internodes called rosettes.  In second season, it bolts, i.e. sends up a flowering stalk with extended internodes bearing flower and fruits. Root vegetables like carrots and beets; leafy vegetables like lettuce and cabbage; and others like onions are biennial in nature. Perennial plants grow for years, and most of them are woody. Their growth can be divided into juvenile and mature phases. During the first phase, the plant grows vegetatively for several years. In the second phase, reproduction starts, and vegetative and reproductive growth are concurrent. All of our fruit trees and ornamental shrubs and trees are perennial, and some herbaceous plants are also perennial. The above ground parts of such plants are killed in winter while the underground storage structu...

Tillage Tillage is derived from word “Till” means to cultivate, to loose or to open the soil. Simply it means opening of soil. Tillage is practice of working the soil to provide conditions favorable to growth of plants. Objectives of Tillage                 Primary purpose of tillage is to control weeds. Tillage is one of the important mechanical methods of controlling weeds. To destroy hibernating insects live either in the soil or on plant residues or weeds. When the plant residues are buried deeply and weeds are destroyed, the places for living of insects are also destroyed. Insects are also exposed to the sunrays and to attack of birds during cultivation, and are thus destroyed. Tillage improves physical conditions of soil e.g. structure, infiltration or water holding capacity of soil and aid in erosion control in some cases (counter tillage). Tillage increases microbial activity in soil. I...

Irrigation methods Irrigation water may be applied to crops by spreading it on the field   surface, by applying it beneath the soil surface, by spraying it under pressure or by applying it drop by drop. Each of these activity can be accomplished by using different irrigation techniques. Surface Irrigation Subsurface Irrigation Sprinkler Irrigation Drip or Trickle Irrigation

Drip or Trickle Irrigation Drip trickle irrigation in one of the latest methods of irrigation that is becoming popular in areas with water scarcity and coarse soils having high infiltration rate. It minimizes conveyance and other conventional losses such as deep percolation, runoff and soil water through dippers. In this method, irrigation is accomplished by using small diameter plastic lateral lines with devices called emitters or drippers at selected spacing to deliver water drop by drop to the soil surface near the base of the plants. The system applies water slowly to keep the soil moist within the desired range of plant root system. The system operates at less pressure 10 to 15 psi. the emitters dissipate pressure energy from the distribution system by means of orifices, vortexes and tortuous or long flow paths thus allowing a limited volume of water to discharge. Most emitters are placed on ground but they can also be buried. The emitted water moves within sol system largely...

Sprinkler Irrigation In this method water is sprayed into the air and allowed to fall on the ground surface somewhat resembling rainfall. The spray is developed by flow of water under high pressure through small orifices or nozzles. The pressure is usually obtained by pumping. With careful selection of nozzle sizes, operating pressure and sprinkler spacing, the amount of irrigation water required to refill the crop rootzone can be applied nearly uniformly at a rate to suit the infiltration rate of the soil, obtaining efficient irrigation. Suitability                 Sprinkler irrigation can be used for almost all crops except rice and on most soils except very fine textured soils where the infiltration rates are less than 4 mm/hr. It is well suited to sandy soils and small streams. Shallow soils and soils involving extensive land preparation (undulating topography) can be irrigated efficiently....

Subsurface Irrigation In this method of irrigation, water is applied below the ground surface by maintaining an artificial water table at some depth depending upon the soil texture and the depth of the plant roots. Water reaches the plant roots through capillary action. Water may be introduces through open ditches or underground pipe lines such as tile drains or mole drains. The depth of open ditches or tranches varies from 30 to 100 cm and are spread about 15 to 30 cm apart. Suitability                 It is suited to soils having reasonably uniform texture and permeable enough for water to move rapidly both horizontally and vertically within and for some distance below the crop rootzone. The soil profile must also contain barrier against excessive losses through deep percolation, either a nearly impermeable layer in the substratum when artificial water table can be maintained throughout ...

Surface Irrigation (gravity irrigation) In the surface methods of irrigation, water is applied directly to the soil surface from a channel located at the upper reach of the field. The driving force in such irrigation system is gravity and hence alternate name is gravity irrigation or gravity flooding. Two general requirements of prime importance are to obtain high efficiency and uniform distribution of water over the field. Once distributed over the field, water enters the soil and is redistributed by the forces of gravity and capillary to be available for plant use through root system. The surface irrigation is further subdivided into a number of techniques depending on the shape, slope and surface shaping of the field as summarized below. Basin Irrigation Border Irrigation Furrow Irrigation Corrugation Irrigation

Furrow Irrigation This method of irrigation is used in the irrigation of row crops with furrows developed between the crop rows in the planting and cultivating processes. The size and slope of the furrow depends upon the crop grown, equipment used and spacing between crop rows. Water infiltrates into the soil and spread laterally to irrigate the areas between the furrows. The length of time, the water to flow in the furrows depends on the amount of water required to replenish to rootzone and the infiltration rate of the soil and rate of lateral spread of water in the soil. Both large and small irrigation stream can be used by adjusting the number areas where surface drainage is necessary, the furrows can be used to dispose of the runoff from rainfall rapidly. Suitability                 Furrow irrigation can be used to irrigate all crops planted in rows, including orchard and vegetables. This method ...

Corrugation Irrigation It consists of running water in small furrows called corrugations which directs the flow down the slope. In this method, more and smaller furrows are made for water control. This method minimize the crusting effect and used for seed germination sometimes, which have been broadcast.

Border Irrigation This method makes use of parallel ridges to guide a sheet of flowing water as it moves down the slope. A border may be level or graded depending on the provision of no. of some scope in longitudinal direction. The slope in transverse direction is zero in both the cases. In graded border, the land is divided into a number of long parallel uniformly graded strips of land called borders that are separated by low ridges. It has no cross slope but uniform gentle in the direction of irrigation. The essential feature is to provide such a surface that water can flow down with uniform depth. Each strip is irrigated independently by a sheet of water confined by the border ridges. The width of border strip depends on the size of irrigation stream, amount of cross slope, kind and width of farm machinery and the desired accuracy of land leveling. Length of border strips should be limited to 400 meters. Longer strips are advantageous as they reduce the cost of wate...

Basin Irrigation This is the most common simplest and oldest method of controlled irrigation in Pakistan. There are many variations in its use. However, in general, it involves dividing the field into smaller unit areas so that each has a nearly level surface. Ridges are constructed around the field farming basin within which are constructed around the field forming basin filled to the desired depth can be controlled. The basins are filled to the desire depth and the water is retained until it infiltrates into the soil. When irrigating rice the depth of water may be maintained for considerable period of time by allowing water to continue to flow into the basins. Suitability                 Basin irrigation is used on many different soils. The prime important soil character influencing the design of basin is the water infiltration rate. This and the size of the available stream determine the a...

Fertilizer Application Methods Broadcast Application                 Application of fertilizer by hand or by machine as uniformly as possible to the surface of a field is called broadcast method. It is a good practice to apply half the quantity of fertilizer across the field and the remaining half along the field. Fertilizer is usually broadcasted at the time of last plowing. It should be incorporated into the upper soil layer by plowing and planking. It may be left on the surface in some cases. Fertilizer applied at this stage in known as basal dressing. Advantages: this method gives fairly good results in case of crops like cereals and millets (wheat, rice, oat, barley) which are planted in narrow rows o in crops sown by broadcast method because roots of such crops are present everywhere in field. Incorporation of fertilizers into the soil elevates the fertility status of entire plow layer and ...

Organic Matter Soil organic matter is composed of decomposing residues (plants and animals), by-product formed by decomposition, microorganisms and materials resistant to further decomposition. Generally, a mineral soil contains 2-5 %organic matter. Organic matter plays a variety of roles in nutrient, water and biological cycles in soil system. Source of organic matter: common organic waste materials which could be used to increase soil organic matter include animal manures, crop residues, composts, green manure, sewage sludge, food processing wastes, industrial organic wastes, wood manufacturing wastes and municipal wastes. Factor Affecting Organic Matter in Soil The amount of organic matter in soil is the result of two processes: the addition of organic matter and the loss of organic matter through decomposition. The following four factors affect both addition and losses. Management                ...

Climate It is the average weather conditions at a particular place over period of time as determined by temperature, precipitation, wind velocity and other morphological factors. Climate is the dominant factor of soil formation because of the effects of temperature, rainfall and wind. These sub factors affects the rate of chemical, physical and biological processes that are responsible of soil development. The biochemical changes are sensitive to temperature. These changes are favoured by temperature range of 20-30 o C. Temperature also influences the organic matter content of the soil. Decomposition of organic matter is more at higher temperature. Moisture is another important actor in soil formation. Rainfall is the major source of moisture. In areas receiving low rainfall, there is shallow accumulation of carbonates in the soil, in humid areas, acid soils are developed under conditions of intense weathering and leaching. Erosion caused by water may remove upper fertile port...

Significance of Organic Matter Organic matter is a source of nutrients like N, P and S for plants. Organic matter affects both the physical and chemical properties of the soil and its overall health. It increases water infiltration in soil. It increases water holding capacity. Organic matter can hold 20 times moisture of its weight. Organic matter may bind pesticides making them less active and reduce the risk of pollution. Organic matter enhances the biological activity of soil, therefore crop health and vigor is improved. It increases cation exchange capacity and thus nutrient holding capacity of soil. It chelates (binds) nutrients and thus improves their availability. It is a source of energy for soil microorganisms. It buffers changes in pH. It improves physical condition of soil. It gives dark color to soil and so influences soil temperature. Organic matter is source of growth-promoting substances for plants.