Optimizing Irrigation and Fertilization using Lysimeters
|Increasing irrigation at the pod production stage increases the quantity of peanuts|
|Moran Sgoli ,Desert Agro-Research Centers*|
|January 2, 2018|
The amount of water applied (and its price) is an important factor in the profitability of irrigated field crops, especially in water-limited environments. Knowledge of actual crop requirements is the first step in optimizing irrigation regimes.
The most accurate method to measure crop water requirement (evapotranspiration) is by water balance using weighing lysimeters.
A weighing lysimeter is a large soil tank that situated on a scale. By recording the changes in the soil tank weight, we can calculate the amount of water that enters (irrigation and precipitation) and the amount of water that exits through evapotranspiration and drainage. The main disadvantages of using weighing lysimeters in the field are that they are expensive to build and the maintenance is time-consuming.
With the generous help of ICA in Israel, we built 16 in-situ lysimeters in semi-commercial scale permanent research plots at the Western Negev Desert Agro-Research Center (MOP Darom).
Four permanent agricultural plots, each 1- hectare and divided into 16 subplots were each equipped with four weighing lysimeters of about two cubic meters. Water in the lysimeters reaching below the root zone (drainage) is weighed and collected for chemical analysis.
This allows for evaluation of potential deep soil and groundwater contamination and agricultural management strategies to insure sustainability. We perform commercial crop rotations on every plot every year, in order to provide knowledge to local farmers representing their commercial crops of interest.
The permanent plots at MOP Darom have become a platform attracting collaboration of researchers from various disciplines and organizations. These collaborations provide valuable data regarding the complex soil-water-plant-atmosphere interactions in the agro-system.
This, in turn, allows us to perform detailed multi-disciplinary experiments at a relatively low maintenance cost.
Example: Optimizing irrigation of peanuts
Our main results include:
From our results, an irrigation scheduling protocol was developed and published based crop factors and potential evaporation (Penman-Monteith equation). Potential evaporation data is readily accessible from meteorological stations, provided, for example, by a Ministry of Agriculture web site and smart phone application.