نتایج جستجو برای: crop yield

تعداد نتایج: 245617  

2013
Juraj Balkovič Marijn van der Velde Erwin Schmid Rastislav Skalský Nikolay Khabarov Michael Obersteiner Bernhard Stürmer Wei Xiong

Justifiable usage of large-scale crop model simulations requires transparent, comprehensive and spatially extensive evaluations of their performance and associated accuracy. Simulated crop yields of a Pan-European implementation of the Environmental Policy Integrated Climate (EPIC) crop model were satisfactorily evaluated with reported regional yield data from EUROSTAT for four major crops, inc...

2017
Christoph Müller Joshua Elliott James Chryssanthacopoulos Almut Arneth Juraj Balkovic Philippe Ciais Delphine Deryng Christian Folberth Michael Glotter Steven Hoek Toshichika Iizumi Roberto C. Izaurralde Curtis Jones Nikolay Khabarov Peter Lawrence Wenfeng Liu Stefan Olin Thomas A. M. Pugh Deepak K. Ray Ashwan Reddy Cynthia Rosenzweig Alex C. Ruane Gen Sakurai Erwin Schmid Rastislav Skalsky Carol X. Song Xuhui Wang Allard de Wit

Crop models are increasingly used to simulate crop yields at the global scale, but so far there is no general framework on how to assess model performance. Here we evaluate the simulation results of 14 global gridded crop modeling groups that have contributed historic crop yield simulations for maize, wheat, rice and soybean to the Global Gridded Crop Model Intercomparison (GGCMI) of the Agricu...

2009
Yinhong Kang Shahbaz Khan Xiaoyi Ma

This paper provides a comprehensive review of literature related to the assessment of climate change impacts on crop productivity using climate, water and crop yield models. The existing studies present that climate change models with higher spatial resolution can be a way forward for future climate projections. Meanwhile, stochastic projections of more than one climate model are necessary for ...

2015
B. Sinha K. Singh Sangwan Y. Maurya V. Kumar C. Sarkar B. P. Chandra V. Sinha

In this study we use a high-quality data set of in situ ozone measurements at a suburban site called Mohali in the state of Punjab to estimate ozone-related crop yield losses for wheat, rice, cotton and maize for Punjab and the neighbouring state Haryana for the years 2011–2013. We intercompare crop yield loss estimates according to different exposure metrics, such as AOT40 (accumulated ozone e...

2012
Vinay Sehgal

Crop yield is the result of complex interaction among factors of soil, atmosphere, plant genotype, and management practices adopted. These complex interactions of crop with various factors and of factors among themselves make the crop yield modeling a difficult task. Several methods of crop yield forecasting have been developed ranging from purely statistical to agro-meteorological to empirical...

2004
Alexander E. Saak

A study of equilibrium acreage allocation decisions at the farm and regional levels under risk aversion, yield uncertainty, and endogenous crop prices is undertaken in a two-crop, two-region setting. The main insight is that a partial specialization in one crop at a regional level may be an equilibrium dominant strategy relative to the more diversified crop mix produced on farm. This is due to ...

Journal: :تولید گیاهان زراعی 0

in this experiment which was conducted at a field of ramin agriculture and natural resources university (khouzestan, iran) in 2005, the effect of molinate at 0 (weedy check), 2.16, 3.6 and 5 kg/ha and seeding rate of 100, 120 and 140 kg/ha was evaluated on the competition between rice and barnyard grass (echinochloa crus-galli) in a split plot design with four replication. the interaction effec...

Rapeseed needs a sufficient amount of nitrogen for optimal seed yield, but the efficiency of this plant in using nitrogenous (N) fertilizers is low, which causes an increase in N consumption in the cultivation of this plant. The need to maintain a high grain yield necessitates the use of a suitable timely program and manage the consumption of N fertilizers. Thus, a field experiment was conducte...

2014
S. S. Patil

Classification is challenging task on complex features of Remote sensing satellite imageries color pixels variability of patterns. Machine learning techniques have delivered the improved in accuracy of classification of patterns of features. Remote sensing color based imageries having hard to cluster color pixels with variability in intensity of colors. Challenges in estimation of various featu...

2015
Amélie C. M. Gaudin Tor N. Tolhurst Alan P. Ker Ken Janovicek Cristina Tortora Ralph C. Martin William Deen

Cropping sequence diversification provides a systems approach to reduce yield variations and improve resilience to multiple environmental stresses. Yield advantages of more diverse crop rotations and their synergistic effects with reduced tillage are well documented, but few studies have quantified the impact of these management practices on yields and their stability when soil moisture is limi...

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