Field-scale spatial variation in yields and nitrogen fixation of clover-grass leys and in soil nutrients

A Nykänen,Lindström Kemppainen,L Jauhiainen

doi:10.2137/145960608787235568

Abstract

Biological nitrogen fixation (BNF) plays a crucial role in organic farming and red clover (Trifolium pratense) is cultivated widely in boreal grasslands for BNF. A geostatistical method, model-based kriging, was used to determine the spatial variation in yield, clover content and BNF of clover-grass leys as well as soil chemical properties throughout two fields in 2004-2006. Based on this variation, principal component analysis (PCA) was used to determine the similar patterns of variation. On one location, total dry matter yields of the leys decreased over three production years from 9 700 to 4 100 kg ha-1, clover content from 53 to 26% and BNF from 150 to 40 kg N ha-1, whereas on the other location the yields increased from 6 500 to 7 100 kg ha-1, clover content from 52 to 62% and BNF from 100 to 120 kg N ha-1. Nutrient concentrations in soil also varied greatly within the fields, although this depended on the nutrient species. Kriging combined with PCA described the spatial variation of ley parameters very informatively, but was not as powerful for describing the pattern of nutrients. Based on the spatial dependence determined in the two fields investigated, it seems that the sampling distance should be 80 m for soil nutrients, 100 m for yield and 60 m for clover content and BNF determination, respectively.;

Highlights

Biological nitrogen fixation (BNF) of legumes is important in organic plant production, since it forms the basis for the N supply in organic production method
The aim of this study was to determine the spatial variation in yield, clover content, BNF and soil nutrients of leys within two selected field sites in Nykänen, A. et al Variation of ley yield, BNF and soil nutrients eastern Finland and during three production years
Total dry matter yields of the leys in Juva diminished from almost 10 000 kg ha-1 in 2004 to less than half of that in 2006, which indicates a decrease in yield with increasing age of the ley

Summary

Introduction

Biological nitrogen fixation (BNF) of legumes is important in organic plant production, since it forms the basis for the N supply in organic production method. BNF could be utilised in conventional farming, too, to reduce the fossil energy consumption for. Perennial grasslands are cultivated for fodder production in areas where agriculture is based on livestock production. Red clover (Trifolium pratense) is one of the most common forage legumes in temperate grasslands. It is cultivated in a mixture with grasses and cut two or three times during the growing season. Perennial red clover -based leys are used as green manure in crop rotations

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