Research Paper
Mehdi Jafari talukolaee; Rassol Nouri Khajebelagh
Abstract
The present study was conducted with the aim of investigating the productivity and energy indicators of paddy, wheat, fodder corn, seed corn and citrus fruits in the Tajan plain in the crop year 1401-02. Then sampling was done based on 300 designed questionnaires. The collected information includes man-days, ...
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The present study was conducted with the aim of investigating the productivity and energy indicators of paddy, wheat, fodder corn, seed corn and citrus fruits in the Tajan plain in the crop year 1401-02. Then sampling was done based on 300 designed questionnaires. The collected information includes man-days, working hours of machinery, fuel consumption of machinery, consumption of nitrogen, phosphate, potassium fertilizers, consumption of various types of chemical pesticides, including herbicides and fungi. Pesticides and insecticides were in liters per hectare, the amount of water consumed was in cubic meters per hectare, the amount of seeds consumed was in kilograms per hectare and the amount of production. The results showed that the highest amount of energy in Tajan plain in the input energy sector for paddy crop (593256 mega joules per hectare), output energy for fodder corn product (141795 mega joules per hectare), net energy for fodder corn product (110758.53 mega joules per hectare) and energy efficiency was also for fodder corn product (1.1 kg/mega joules). Also, according to the obtained results, it was found that in all the products, the four inputs of water consumption, nitrogen fertilizer, machinery and fuel have the highest amount. The results of the investigation of the physical productivity of water showed that the highest productivity in the Tajan plain is related to fodder corn and the lowest productivity is related to rice 0.5 kg/m3. In general, to increase the productivity of lands and products in terms of productivity and energy indicators, it is necessary to use the cultivation of plants with appropriate performance, the highest level of productivity and the lowest level of input consumption. research, fodder corn had more suitable conditions.
Research Paper
2
Saeid Habibi; Mojtaba Khoshravesh; Rassol Nouri Khajebelagh
Abstract
Water, food, and energy are three essential sources for maintaining life and fostering socio-economic development, and they are inseparably interconnected. The aim of the present study was to examine the indicators of water, energy efficiency, and global warming potential of major agricultural products, ...
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Water, food, and energy are three essential sources for maintaining life and fostering socio-economic development, and they are inseparably interconnected. The aim of the present study was to examine the indicators of water, energy efficiency, and global warming potential of major agricultural products, namely wheat and rapeseed, in two different climates in Sari and Sharifabad plains. To investigate these indicators in wheat and rapeseed crops, data from the agricultural year 1400-1401 were utilized. Initially, the sample size was determined based on the Cochran formula. Subsequently, sampling was done using a questionnaire designed by the researchers themselves. The questionnaires numbered 300, and the collected information included input consumption and production quantities. The results of water physical efficiency showed that the average water physical efficiency in Sari plain for wheat and rapeseed crops was 1.13 and 0.67 kilograms per cubic meter, respectively, while in Sharifabad plain, it was 0.83 and 0.35 kilograms per cubic meter, respectively. Furthermore, the results for energy indicators indicated that the highest level of input energy in Sari and Sharifabad plains for wheat was 80618 and 71072 megajoules per hectare, respectively. The results also showed that greenhouse gas emissions were higher in Sari than in Sharifabad, attributed to excessive fertilizer and pesticide use in Sari. The highest greenhouse gas emissions in Sari for wheat were 2495 kilograms of CO2 per hectare, and in Sharifabad, it was 2299 kilograms of CO2 per hectare. Overall, the results indicated that crop performance in humid regions is higher than in dry and semi-dry regions, and this indicator depends on various parameters, including water consumption and management discussions.
Research Paper
7
reza saeidi
Abstract
For an accurate irrigation schedule, should be estimated the daily soil water depletion amount during the crop growth period. Soil water depletion is dependent to daily evapotranspiration amount. In this research, daily evapotranspiration of S.C 704 maize was measured in mini-lysimeter. Estimation of ...
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For an accurate irrigation schedule, should be estimated the daily soil water depletion amount during the crop growth period. Soil water depletion is dependent to daily evapotranspiration amount. In this research, daily evapotranspiration of S.C 704 maize was measured in mini-lysimeter. Estimation of daily evapotranspiration was done by continuous measurement of soil moisture. Leaves stomatal resistance was measured as daily, and by AP4 Porometer device. Soil water allowable depletion limit in four growth stages of initial(C1), development(C2), mid(C3) and late(C4), was determined based on the leaves stomatal resistance response. The time of leaves stomatal resistance increasing (at each growth stage) relative to control crops, was the time of readily available water ending and doing of new irrigation. Main factor was included of growth stage effect on crop evapotranspiration and water depletion coefficient amounts, which was investigated in a completely randomized basic design, with three replications. Regression functions (models) were used for simulation of soil water allowable depletion coefficient (P) based on the daily evapotranspiration (ETc). The models were calibrated by daily data in initial and development stages, and they were evaluated by daily data in mid and late stages. The FAO-56 linear model was compared with introduced models in this research. The results showed that maize ETc (S.C 704) rate in initial, development, mid, and late stages was in the range of 1.5-4.5, 3.9-7.1, 1.4-7.5, and 0.2-2.1 mm.d-1, respectively. The allowable soil water depletion limit in mentioned stages was calculated as 0.45, 0.66, 0.61 and 0.7, respectively. Different sensitivity in crop growth stages was caused that, readily available water limit not be constant in growth period. The ETc increasing was caused a decreasing in P coefficient, and ETc decreasing was caused an increasing in P coefficient, in growth stages. Linear, exponential, logarithmic, polynomial, power, and FAO-56 linear functions, were investigated. Polynomial function with statistical indices of RMSE=0.00035, NRMSE=0.054, ME=0.0008, CRM=-000005, R2=0.999 and EF=0.999, was the optimal model in estimation of P coefficient. The reason of weak performance in FAO-56 model, was considering the constant limit for readily available water and mean ETc rate in growing season. Therefore, the FAO-56 model was modified. The research result was to estimate the soil water allowable depletion coefficient (by using ETc), without daily measurement of soil moisture. This method will be useful in irrigation scheduling with short rounds, especially. So that, the suitable time and volume of irrigation are determined for water loss prevention.