Staff Publications

Staff Publications

  • external user (warningwarning)
  • Log in as
  • language uk
  • About

    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

    We have a manual that explains all the features 

Current refinement(s):

Records 1 - 3 / 3

  • help
  • print

    Print search results

  • export

    Export search results

  • alert
    We will mail you new results for this query: keywords==Radiation interception
Check title to add to marked list
Analysis of coffee (Coffea arabica L.) performance in relation to radiation levels and rates of nitrogen supply I. Vegetative growth, production and distribution of biomass and radiation use efficiency
Bote, Adugna Debela ; Ayalew, Biruk ; Ocho, Fikre L. ; Anten, Niels P.R. ; Vos, Jan - \ 2018
European Journal of Agronomy 92 (2018). - ISSN 1161-0301 - p. 115 - 122.
Light extinction - Orthotropic stem - Plagiotropic branch - Radiation interception - Shade avoidance

Intensively managed full-sun coffee (Coffea arabica L.), is potentially highly productive, but has shown disappointingly low yield performance, as adequate resource supplies (especially plant nutrition) are needed to sustain the productivity. In order to underpin rational radiation and nutrient management, the current study focussed on growth and development of 2.5 years old trees in relation to nitrogen supply in combination with several degrees of radiation. Three coffee varieties were grown under four levels of radiation (30–100% full sun) and four rates of nitrogen supply (0–88 g tree−1 y−1), arranged in a randomized split-split plot design at Jimma University horticultural farm, Ethiopia, and their biomass increment (growth) and allocation, and crown characteristics were measured. Growth responded positively to both radiation and nitrogen supply, with positive interactions for several plant attributes (including number and length of branches, numbers of pairs of leaves per branch, radiation use efficiency). Plant height and area per leaflet declined with higher radiation level, while the positive effect of larger N supply on these attributes declined with increase in radiation. Branch length and leaf dry weight showed the most positive plasticity in response to higher radiation. Specific leaf area declined from 187 in shade (reducing sunlight to 30%) to 109 cm2 g−1 in full sun without effect of N. Positive effects of nitrogen on growth and biomass production were mediated through higher radiation-use efficiency, RUE, ranging from 0.23 to 0.46 g MJ−1 (PAR). Variables associated with dry matter partitioning were modestly responsive to either N or radiation. All these responses were consistent across the three varieties. The study enhanced the understanding of vegetative growth and biomass production of coffee trees and explored traits that underlie these patterns. The study also yielded essential information for managing shade and nitrogen supply in both open sun and agroforestry systems and yielded basic information for developing coffee growth models

Maize-grain legume intercropping for enhanced resource use efficiency and crop productivity in the Guinea savanna of northern Ghana
Kermah, Michael ; Franke, Angelinus C. ; Adjei-nsiah, Samuel ; Ahiabor, Benjamin D.K. ; Abaidoo, Robert C. ; Giller, Ken E. - \ 2017
Field Crops Research 213 (2017). - ISSN 0378-4290 - p. 38 - 50.
LER - Net benefit - Radiation interception - Soil fertility - Spatial arrangement
Smallholder farmers in the Guinea savanna practise cereal-legume intercropping to mitigate risks of crop failure in mono-cropping. The productivity of cereal-legume intercrops could be influenced by the spatial arrangement of the intercrops and the soil fertility status. Knowledge on the effect of soil fertility status on intercrop productivity is generally lacking in the Guinea savanna despite the wide variability in soil fertility status in farmers’ fields, and the productivity of within-row spatial arrangement of intercrops relative to the distinct-row systems under on-farm conditions has not been studied in the region. We studied effects of maize-legume spatial intercropping patterns and soil fertility status on resource use efficiency, crop productivity and economic profitability under on-farm conditions in the Guinea savanna. Treatments consisted of maize-legume intercropped within-row, 1 row of maize alternated with one row of legume, 2 rows of maize alternated with 2 rows of legume, a sole maize crop and a sole legume crop. These were assessed in the southern Guinea savanna (SGS) and the northern Guinea savanna (NGS) of northern Ghana for two seasons using three fields differing in soil fertility in each agro-ecological zone. Each treatment received 25 kg P and 30 kg K ha−1 at sowing, while maize received 25 kg (intercrop) or 50 kg (sole) N ha−1 at 3 and 6 weeks after sowing. The experiment was conducted in a randomised complete block design with each block of treatments replicated four times per fertility level at each site. Better soil conditions and rainfall in the SGS resulted in 48, 38 and 9% more maize, soybean and groundnut grain yield, respectively produced than in the NGS, while 11% more cowpea grain yield was produced in the NGS. Sole crops of maize and legumes produced significantly more grain yield per unit area than the respective intercrops of maize and legumes. Land equivalent ratios (LERs) of all intercrop patterns were greater than unity indicating more efficient and productive use of environmental resources by intercrops. Sole legumes intercepted more radiation than sole maize, while the interception by intercrops was in between that of sole legumes and sole maize. The intercrop however converted the intercepted radiation more efficiently into grain yield than the sole crops. Economic returns were greater for intercrops than for either sole crop. The within-row intercrop pattern was the most productive and lucrative system. Larger grain yields in the SGS and in fertile fields led to greater economic returns. However, intercropping systems in poorly fertile fields and in the NGS recorded greater LERs (1.16–1.81) compared with fertile fields (1.07–1.54) and with the SGS. This suggests that intercropping is more beneficial in less fertile fields and in more marginal environments such as the NGS. Cowpea and groundnut performed better than soybean when intercropped with maize, though the larger absolute grain yields of soybean resulted in larger net benefits.
How Age of Transplants from In Vitro Derived Potato Plantlets Affects Crop Growth and Seed Tuber Yield After Field Transplanting
Lommen, W.J.M. - \ 2015
Potato Research 58 (2015)4. - ISSN 0014-3065 - p. 343 - 360.
Ground cover - Harvest index - In vitro plantlets - LUE - Minitubers - Radiation conversion coefficient - Radiation interception - Radiation use efficiency - Seed production - Transplant age - Tuber formation - Yield formation

In vitro produced plantlets are used in potato seed systems for production of minitubers under protected conditions or for production of transplants to be transplanted to the field. Three field experiments were carried out to analyse how transplant age (Age) affected the field performance. In the main experiments, 2-, 3- and 4-week-old transplants of the very early cultivar Gloria (Exp. 1) and the mid-early cultivar Bintje (Exp. 2) were produced in a glasshouse. Exp. 3 was a check experiment in which 2- and 3-week-old transplants of cv. Gloria were produced in growth chambers under conditions that were non-inductive for tuberization (24-h photoperiod, high temperature). Ground cover (GC) was assessed weekly and weights of the tuber and canopy fractions were assessed at 0, 14, 28, 42, 56, 70 and 84 days after transplanting (DAT). Yield analysis [accumulated intercepted radiation (AIR), radiation use efficiency (RUE), total dry weight (TDW), harvest index (HI) and tuber dry matter concentration] was carried out; the fraction dry matter (DM) allocated to the tubers and the canopy was calculated for three 2-week intervals after field transplanting. When raised in the glasshouse, older transplants were more advanced in tuber formation and canopy growth than younger transplants and had a higher GC at transplanting. However, crops from younger transplants produced significantly higher fresh tuber yields than crops from older transplants in the later part of the growing period in Exp. 1; the same trend was observed in Exp. 2. AIR was the most important yield component affected by transplant age; RUE, HI and tuber dry matter concentration were not or not meaningfully affected by transplant age. In the first 2 weeks after field transplanting, a very high percentage of the DM produced (>85%) was allocated to tuber growth in crops from the oldest transplants. This reduced AIR severely. The results show clearly that seed crops from younger transplants will perform better than crops from older transplants or at least perform at par. Implications for transplant production management are discussed.

Check title to add to marked list

Show 20 50 100 records per page

 
Please log in to use this service. Login as Wageningen University & Research user or guest user in upper right hand corner of this page.