Analysis of economical, social and environmental aspects of agroforestry systems of trees and perennial herbaceous plants

S. Rancane¹*, K. Makovskis², D. Lazdina², M. Daugaviete², I. Gutmane¹ and P. Berzinš¹

¹LLU Research Institute of Agriculture, Zemkop bas instituts 7, Skr veri, Latvia
2Latvia State Forest Research Institute Silava, Rigas 11, Salaspils, Latvia; *Correspondence: 1sarmite.rancane@inbox.lv

Abstract:

The aim of this study was to determine the economic, social and environmental aspects, that promote choosing an agroforestry system and continuing agricultural production instead of simple afforestation of agricultural land. Material for the study was collected in an experimental demo field located in the central part of Latvia (56°41 N and 25°08 E) established in the spring of 2011, nearby Skr veri. Two legumes – fodder galega (Galega orientalis Lam.) ‘Gale’, poor-alkoloid lupine (Lupinus polyphyllus L.) ‘Valfrids’ and two perennial grass cultivars – reed canary grass (RCG) (Phalaris arundinacea L.) ‘Bamse’ and festulolium (x Festulolium pabulare) ‘Felina’ were sown between the tree rows and in monoculture on drained mineral soil. Four different fertilisation treatments for herbaceous plants – control (without fertiliser), mineral fertilisers, wastewater sludge and wood ash were used. Biomass, seed yield, agricultural management cost have been investigated since the establishment of experiment in 2011. Potential benefits from growing herbaceous plants for seed, biomass production and possible future income from tree wood and non-wood goods were calculated. Management cost of agroforestry system, plantation forest and traditional sowing were analyzed. The growth of herbaceous plants for seed production together with hybrid aspen in agroforestry system during a 5 year period has a positive balance with all types of fertilisers. The growth of herbaceous plants in a monoculture for biomass production in a 3 year period had a positive balance for all types of organic fertilisations at both cutting frequencies. Positive balance by applying mineral fertiliser was achieved only at two-cut cutting regime.

Key words:

The effect of fertiliser type on hybrid aspen increment and seed yield of perennial grass cultivated in the agroforestry system

A. Bardule¹,*, S. Rancane², I. Gutmane², P. Berzins², V. Stesele², D. Lazdina¹ and A. Bardulis¹

¹Latvia State Forest Research Institute ‘Silava’, Riga street 111, Salaspils, Latvia;
*Correspondence: arta.bardule@silava.lv
²LLU Research Institute of Agriculture, Zemkopibas instituts 7, Skriveri, Latvia

Abstract:

Agroforestry is a perspective way of biomass production which combines simultaneous growing of woody plants with agricultural crops on the same area for different purposes. The advantage of agroforestry lies in the improved efficiency of resource utilisation and smaller competition of plants for nutrients. In this system the woody plants are less influenced by lasting periods of drought, and a stable annual increase in biomass is ensured. Accordingly, agroforestry is biologically more productive, economically – more favourable, and it is more sustainable than the monocultures of forestry or agriculture separately. The work was done to test the effect of fertiliser type on the increment of two clones of hybrid aspen (Populus tremuloides x Populus tremula) and the seed yield of perennial grasses (Phalaris arundinacea L., x Festulolium pabulare) and legumes (Lupinus polyphyllus L., Galega orientalis Lam.) cultivated in the agroforestry system on loam/sandy soils. Fertilisers used at the planting were wastewater sludge (dose 10 tDM ha-1) and wood ash (dose 6 tDM ha-1). Wastewater sludge fertilisation increased the stem length of hybrid aspen by 20% after the first growing season. The effect of wastewater sludge fertilisation on stem length was still significant after the second growing season. Soil and soil solution analysis indicated that the main Hybrid aspen growth response was due to the P and N supplied by fertiliser. Reed canary grass (RCG), festulolium and fodder galega can be successfully cultivated for seeds in the first year of use, locating the crop fields in the plantations of energy plants interchangeably with trees. The use of wastewater sludge provided an essential increase in seed yields for all species of herbaceous plants. However, the influence of fertilisers on the grass species was different: the greatest increase in seed yields was established by the use of wastewater sludge in RCG, mineral fertiliser in festulolium, and ash in galega, and the fertilisation provided the seed yield increase of 136%, 31% and 163%, respectively.

Key words:

agroforestry, fertilisers, hybrid aspen, perennial grasses