Cette recherche s'applique uniquement aux ressources en bibliothèque.
12 554 résultats
Trier par:
Ajouter à la liste:
Étendre à toutes les références (sans texte intégral)
    • Article
    Sélectionner

    Summaries of Group Discussion: Dryland Agriculture: Technological, Institutional, Infrastructural and Policy Imperatives

    Nagaraj, N
    2014
    AgEcon Search: Research in Agricultural and Applied Economics
    Disponible
    Plus…
    Titre: Summaries of Group Discussion: Dryland Agriculture: Technological, Institutional, Infrastructural and Policy Imperatives
    Auteur: Nagaraj, N
    Sujet: Land Economics/Use
    Fait partie de: 2014

    • Article
    Sélectionner

    The Price of Land: Acquisition, Conflict and Consequence

    Chakravorty, Sanjoy
    2014
    AgEcon Search: Research in Agricultural and Applied Economics
    Disponible
    Plus…
    Titre: The Price of Land: Acquisition, Conflict and Consequence
    Auteur: Chakravorty, Sanjoy
    Sujet: Land Economics/Use
    Fait partie de: 2014

    • Article
    Sélectionner

    Understanding Soil as an Open System and Fertility as an Emergent Property of the Soil System

    Nicolodi, Margarete, Gianello, Clesio
    2014
    AgEcon Search: Research in Agricultural and Applied Economics
    Disponible
    Plus…
    Titre: Understanding Soil as an Open System and Fertility as an Emergent Property of the Soil System
    Auteur: Nicolodi, Margarete; Gianello, Clesio
    Sujet: Land Economics/Use
    Description: The application of the principles of thermodynamics and General Systems Theory is responsible for important progress in the study of soil and its fertility, and this application can even improve our understanding of the processes that govern the functioning of soil and determine the magnitude of soil fertility. Consequently, we can improve the evaluation and practices recommended for preserving or improving the soil and its fertility, contributing to sustainable food production. Recalling how the concept and human perception of soil have evolved is fundamental to improve our understanding. Thus, this article aims to encourage people to reflect on the application of the principles of thermodynamics of non-equilibrium and General Systems Theory in studying the soil and its fertility and to participate in constructing a new notion of soil fertility, able to express what is perceived by plants. Several authors in the last century have considered the soil to be an open system; however, this approach is a recent in Brazil. Fertility can be coherently understood as one of the emergent properties of the soil system by applying the principles of thermodynamics of non-equilibrium and General Systems Theory to the study of soil.
    Fait partie de: 2014

    • Article
    Sélectionner

    Reducing Egypt Rock Phosphate Use in Zea mays Cultivation on an Acid Soil Using Clinoptilolite Zeolite

    Aainaa, Hasbullah Nur, Ahmed, Osumanu Haruna, Kasim, Susilawati, Majid, Nik Muhamad Ab
    2014
    AgEcon Search: Research in Agricultural and Applied Economics
    Disponible
    Plus…
    Titre: Reducing Egypt Rock Phosphate Use in Zea mays Cultivation on an Acid Soil Using Clinoptilolite Zeolite
    Auteur: Aainaa, Hasbullah Nur; Ahmed, Osumanu Haruna; Kasim, Susilawati; Majid, Nik Muhamad Ab
    Sujet: Land Economics/Use
    Description: Insufficient supply of P for initial growth of crops does not only limit N uptake but it also leads to poor yield of crops. In acidic soils of the tropics, sorption of P occurs mainly on surfaces of Fe and Al oxides and hydroxides. Most of the P added through mineral fertilizers is fixed by high Al and Fe oxide concentrations and transformed into insoluble P compounds. Reduction of Al and Fe is important so as to ensure adequate supply and readily available P for crops uptake. A number of studies using zeolites as an amendment in the fertilization programs of crops have improved crops production, nutrients uptake, and nutrients use efficiency. However, there is dearth of information on the use of clinoptilolite zeolite (CZ) to reduce P fixation not to mention reduction of N, P, and K fertilizers use in agriculture. This study was conducted to: (i) determine dry matter production, nutrients concentration, nutrients uptake, and use efficiency of Zea mays (Hibrimas variety) by including CZ in the fertilization program of Zea mays planted on an acidic soil, and (ii) determine the effect of including CZ in the fertilization program of Zea mays on selected chemical properties of an acidic soil. Egypt rock phosphate (ERP), urea, and muriate of potash were used in this study. Seventy five percent (w/w) of the recommended N, P, and K fertilizers for Zea mays were combined with CZ. Standard procedures were used to determine soil pH, inorganic nitrogen, available phosphorus, exchangeable aluminium, iron, potassium, calcium, magnesium, and organic matter before and after planting. Zea mays were harvested at tasselling stage and measured for dry matter production, nutrients uptake and use efficiency. The effect of CZ application with 75% of fertilizers (E2) and 100% fertilizers (E1) were statistically similar for selected soil chemical properties, dry matter production, nutrients concentration, uptake of nutrients, and nutrients use efficiency except for N. Nitrogen use efficiency for E2 was better than that of E1. These findings suggest that adoption of CZ with 25% reduction of N, P, and K fertilizers are useful. Further field trials and economic analysis are recommended to confirm the findings of this study. These aspects are being investigated in our on-going field experiments.
    Fait partie de: 2014

    • Article
    Sélectionner

    Effects of Variety and Spacing on Yield Indices of Open-Pollinated Maize in Asaba Area of Delta State

    Enujeke, E. C
    2013
    AgEcon Search: Research in Agricultural and Applied Economics
    Disponible
    Plus…
    Titre: Effects of Variety and Spacing on Yield Indices of Open-Pollinated Maize in Asaba Area of Delta State
    Auteur: Enujeke, E. C
    Sujet: Land Economics/Use
    Description: This study was carried out in the Teaching and Research Farm of Delta State University, Asaba Campus (Nigeria) from March to December in 2008 and replicated between March and December, 2009, to evaluate the effects of variety and spacing on yield indices of Open-pollinated maize. It was a factorial experiment carried out in a Randomized Complete Block Design (RCBD) with four replicates. Four open-pollinated varieties (Suwan -1- SR, ACR97, BR9922-DMRSF2 and AMATZBRC2WB) were evaluated under three different plant spacing for such yield indices as number of cobs/plant, cob length, grain weight and number of grains/cob of maize. The results obtained indicated that variety BR9922-DMRSF2 was outstanding with number of cobs/plant of 1.7 in both 2008 and 2009, cob length of 27.7 cm and 26.7 cm in 2008 and 2009, respectively. Its grain weight was 4.7 t/ha in 2008 and 4.9 t/ha in 2009, and its number of grain/cob was 467.7 in 2008, and 463.9 in 2009. Plants sown at spacing of 75 cm x 15cm had higher number of cobs/plant of 1.9 in both 2008 and 2009.Their grain weights (t/ha) were 5.0 in 2008 and 5.2 in 2009, their cob lengths were 18.6cm in 2008 and 20.1cm in 2009, while their number of grains/cob were 363.0 in 2008, and 369.0 in 2009. The results of interaction showed that except variety x space, the parameters investigated were all significantly (P < 0.05) different and affected yield indices of open-pollinated maize. Based on the findings of the study, it was recommended that (i) open-pollinated variety BR9922-DMRF2 be grown in the study area for increased grain yield indices of maize. (ii) Plant spacing of 75 cm x 15 cm which resulted in higher number of cobs/plant and higher grain weight be adopted in maize production.
    Fait partie de: 2013

    • Article
    Sélectionner

    Yield Characteristics of Moringa oleifera Across Different Ecologies in Nigeria as an Index of Its Adaptation to Climate Change

    Ndubuaku, U. M, Ndubuaku, T. C. N, Ndubuaku, N. E
    2014
    AgEcon Search: Research in Agricultural and Applied Economics
    Disponible
    Plus…
    Titre: Yield Characteristics of Moringa oleifera Across Different Ecologies in Nigeria as an Index of Its Adaptation to Climate Change
    Auteur: Ndubuaku, U. M; Ndubuaku, T. C. N; Ndubuaku, N. E
    Sujet: Land Economics/Use
    Description: The pod and yield characteristics of Moringa oleifera plants grown in Ibadan (Rainforest vegetation), Nsukka (Forest-derived savannah vegetation) and Jos (arid derived savannah vegetation) were evaluated from 2007- 2009 to assess adaptability of the plant to climate change threats. The rainfall and temperature distribution in the three locations varied over the years. The Moringa oleifera plants grown at Ibadan had the greatest pod and seed yield followed by those at Nsukka and Jos in that order. The annual pod and seed production capacities of the plants differed significantly (p < 0.05) in the different locations. The overall annual pod and seed production per location, including yield characteristics, did not differ significantly throughout the years of study. Moringa oleifera was therefore found to be a suitable crop adaptable to various environmental and climatic changes in Nigeria.
    Fait partie de: 2014

    • Article
    Sélectionner

    Determining Land Values Using Ordinary Least Squares Regression

    Taylor, Mykel, Schurle, Bryan, Rundel, Brady, Wilson, Bill
    2015
    AgEcon Search: Research in Agricultural and Applied Economics
    Disponible
    Plus…
    Titre: Determining Land Values Using Ordinary Least Squares Regression
    Auteur: Taylor, Mykel; Schurle, Bryan; Rundel, Brady; Wilson, Bill
    Sujet: Land Economics/Use
    Description: Agricultural land values have increased by an average of 21 percent each year since 2010 until recently when commodity prices dropped substantially. The accompanying decrease in profitability raises concerns that current land prices are not sustainable. This study presents a regression analysis of land prices in Kansas using data from 2012 through June 2014. Regression allows valuation of individual characteristics of land parcels as well as time adjustments. Prices projected by the model trended upward through 2013, but decreased between the last quarter of 2013 and the first quarter of 2014, suggesting that prices for land may have peaked in 2013.
    Fait partie de: 2015

    • Article
    Sélectionner

    Rapporteurs' Report: Development of Dryland Agriculture: Technological, Institutional, Infrastructural and Policy Imperatives

    Nagaraj, N
    2013
    AgEcon Search: Research in Agricultural and Applied Economics
    Disponible
    Plus…
    Titre: Rapporteurs' Report: Development of Dryland Agriculture: Technological, Institutional, Infrastructural and Policy Imperatives
    Auteur: Nagaraj, N
    Sujet: Land Economics/Use
    Fait partie de: 2013

    • Article
    Sélectionner

    Effects of Short-term Tillage of a Long-term No-Till Land on Available N and P in Two Contrasting Soil Types

    Dyck, Miles, Malhi, Sukhdev. S, Nyborg, Marvin, Puurveen, Dick
    2015
    AgEcon Search: Research in Agricultural and Applied Economics
    Disponible
    Plus…
    Titre: Effects of Short-term Tillage of a Long-term No-Till Land on Available N and P in Two Contrasting Soil Types
    Auteur: Dyck, Miles; Malhi, Sukhdev. S; Nyborg, Marvin; Puurveen, Dick
    Sujet: Land Economics/Use
    Description: The effects of short-term (4 years) tillage (hereafter called reverse tillage [RT]) of land previously under long-term (29 or 30 years) no-till (NT), with straw management (straw removed [SRem] and straw retained [SRet]) and N fertilizer rate (0, 50 and 100 kg N ha-1 in SRet, and 0 kg N ha-1 in SRem plots) were determined in autumn 2011 on ammonium-N, nitrate-N and extractable P in the 0-7.5, 7.5-15 and 15-20 cm soil layers at Breton (Gray Luvisol [Typic Cryoboralf] loam) and Ellerslie (Black Chernozem [Albic Argicryoll] loam), Alberta, Canada. There was no significant effect of RT and straw on ammonium-N, nitrate-N and extractable P in soil. Ammonium-N in soil increased significantly (but small) with N rate in many cases at both sites. Nitrate-N in soil increased with increasing N rate from 0 to 100 kg N ha-1 rate at Ellerslie, and up to 50 kg N ha-1 rate at Breton. Etractable P in soil decreased markedly with increasing N rate up to 100 kg N ha-1 at Breton and up to 50 kg N ha-1 at Ellerslie. In summary, increased N fertilizer rates were usually associated with decreased extractable P and increased nitrate-N in soil, but RT and straw had no effect on these nutrients in soil.
    Fait partie de: 2015

    • Article
    Sélectionner

    Contribution of Wildlife to the Value of U.S. Southern Forestland

    Straka, Thomas J
    10 June 2011
    AgEcon Search: Research in Agricultural and Applied Economics
    Disponible
    Plus…
    Titre: Contribution of Wildlife to the Value of U.S. Southern Forestland
    Auteur: Straka, Thomas J
    Sujet: Land Economics/Use
    Description: Rural appraisers should be aware of the important contribution wildlife values and hunting leases make to forestland value. Many rural appraisals take place on small family holdings that constitute about 62 percent of private forestland in the United States. Roughly 12 percent of these small forest holdings are leased for hunting or some other recreational use, producing significant annual revenue. The methodology to value these contributions is described. Using southern hunting lease revenues and a six percent real discount rate, hunting leases increased forestland values by $184.00 per acre on average, certainly a significant contribution to value.
    Fait partie de: 10 June 2011