A field experiment was conducted in split plot design with four replications at Research Farm of CCS Haryana Agricultural University, Hisar, India during two consecutive years (2002-03 and 2003-04) to evaluate impact of agrometerological variables on nitrogen uptake and crude protein content in wheat. The experiment comprised of twelve treatments: two dates of sowing; D₁-20^th November and D₂-20^th December and two planting systems; P₁-Flat bed and P₂-Furrow irrigated raised bed planting system in main plot and three nitrogen levels; N₁-120, N₂-150 and N₃-180 Kg N/ha in sub plots. Agrometeorological indices: heat unit, absorbed photosynthetically active radiation, heat and radiation use efficiencies, vapour pressure deficit were computed at different phenophases. Nitrogen uptake, crude protein content in grain and biomass were estimated in all the treatments. Nitrogen uptake was minimum at tillering and maximum at maturity in all the treatments during both years. It was higher at all the growth stages: tillering, jointing, booting, anthesis, milking and physiological maturity in 20^th November sown wheat crop as compared to 20th December sown in both years. The nitrogen uptake at different stages was marginally higher under flat bed planting system as compared to furrow irrigated raised bed planting system. However, the nitrogen content was numerically higher under furrow irrigated raised bed planting system than that of flat bed sowing. The progressive increase in nitrogen levels 120 to 180 kg ha^-1 had significantly enhanced the N uptake in grains of wheat in both the years. The crop season had a strong effect on the interaction among various variables. The interaction between sowing date and nitrogen levels for nitrogen uptake in grains and interactions between D &time; N and among D &time; P &time; N for grain yield were significant only in first year. A multiple regression equation was developed for estimation of nitrogen uptake using agronomic traits and agrometeorological indices. Variability in nitrogen uptake was explained by radiation use efficiency and heat units during milking and vapour pressure deficit during physiological maturity to the maximum extent up to 98 percent. It is suggested that agrometerological parameters should be considered for sustainable wheat production through precision agriculture.

View full abstract

A field experiment was conducted at crop research farm, Chaudhary Charan Singh Haryana Agricultural University, Hisar, during the kharif seasons of 2004 and 2005 to find out suitable spacing for pearl millet hybrids along with N & P levels so as to increase the productivity of pearl millet. The experiment was laid out in split plot design allocating two hybrids and three plant densities in main plots and four fertility levels in sub plots replicated thrice. HHB-67-2 showed significantly higher dry matter accumulation plant^-1 (9.65 %) at harvest, leaf area plant^-1 (9.34 %) at 55 DAS, leaf area index (8.87 %) and leaf area duration (9.65 %) at 41 to 55 DAS and crop growth rate (8.00) at 56 DAS to harvest over HHB-67 in first year. The fertility level 90 kg N + 45 kg P₂O₅ ha^-1 recorded significantly higher dry matter accumulation plant^-1, leaf area plant^-1, leaf area duration and crop growth rate over control and 30 kg N + 15 kg P₂O₅ in both the crop seasons. Hybrid HHB 67-2 recorded significantly higher biological yield over HHB-67 in both the seasons. However 60 kg N + 30kg P₂O₅ ha^-1 caused significant difference in biological yield over control and 30 kg N + 15 kg P₂O₅ ha^-1 +. HHB 67-2 recorded relatively higher value for consumptive water use and water use efficiency. The plant density of 45 × 12 cm produced significantly higher biological yield in both the seasons over 30 × 12 and 60 × 12 cm densities.

View full abstract

Tree litterfall was measured and nitrogen (N) return by tree litterfall was estimated in three plots, F0, F10, and F35, with different fire histories (protected from fire for 0, 10, and 35 years, respectively) in dry dipterocarp forests (DDF) in northeast Thailand. Annual litterfall was 3.92, 7.13, and 8.79 Mg ha^-1, for F0, F10, and F35, respectively. Leaf litter was the main component in all the plots, ranging from 67.4 % to 77.9 %, peaking in the dry season. Other components of the litterfall had no clear seasonality. The N concentration of the tree litterfall increased in the rainy season and decreased in the dry season in all three plots. The N return due to the tree litterfall was estimated to be 33.4, 75.2, and 123.8 kg ha^-1, for F0, F10, and F35, respectively. Fire protection increased the N return by tree litterfall, as well as tree litter production in DDF.

View full abstract

Biomass and dry matter production in 12- to 14-year-old planted forests (including three exotic and three indigenous species) and secondary forest, and the biomass of grasslands were studied in Sakaerat to quantify the capability of plantations to rehabilitate degraded tropical lands. The reforestation of Imperata cylindrica grasslands enhanced the aboveground biomass growth by 5 to 37 times 12 years after planting. Exotic species, especially two Acacia species, accumulated greater biomass in their aboveground and belowground parts than did indigenous species and secondary vegetation at a similar age, and reached or surpassed the biomass in secondary or natural forests within the same area. Indigenous species also accumulated biomass at rates higher than those of secondary vegetation. Aboveground net primary production (ANPP) was greater in plantations of exotic species than in plantations of indigenous species, which had ANPP similar to those in secondary forest. The high ANPP in plantations of exotic species, including one Acacia and Eucalyptus plantation, was associated with higher annual leaf production and shorter leaf lifetime, combined with a small leaf biomass. The rate at which photosynthates were allocated to biomass was similar for plantations of exotic and indigenous species, but was lower in secondary forest than in plantations. The results showed the superiority of artificial plantations over natural regeneration for the rapid restoration of grassland in Sakaerat.

View full abstract

The production of wheat is one of the most important breeding targets in India. The major constraints in the productivity are based on the limiting usage of water. In this mini-review, the focus is on the physiological traits of wheat plants to obtain the tolerance against heat and drought stress. This will encourage the breeding program on wheat in semi arid tropics like India.

View full abstract

To know the effect of plantation on biodiversity in a degraded land, we compared butterfly fauna between a heavily degraded area dominated by grasses, Themeda triandra and Heteropogon contortus, and a nearby plantation forest both on Lombok, Indonesia. We found that forest plantation onto the degraded land did not damage the butterfly fauna in planted area. Extrapolating the present results we discuss impacts on biodiversity that we have to consider when we are engaged in an afforestation and reforestation Clean Development Mechanism project.

View full abstract

In order to elucidate the effects of short-rotation harvesting on microbial biomass and nitrogen (N) mineralization in soil, we studied Gmelina arborea Roxb. (yemane) plantations and the mixed planting of a legume cover crop in East Kalimantan. The microbial biomass carbon (MBC) and microbial biomass nitrogen (MBN) decreased by approximately 40 % to 50 % in the plantation plots than in a secondary forest plot. The MBC increased with the stand age in the plantation plots, while the MBN remained low. In a mixed plot of yemane and legumes, the MBC, MBN, and N mineralization rate were approximately the same as those in a 10-yr plantation plot without cutting; however, these values were higher than those in a 4-yr coppice plot after the cutting of a 6-yr plantation. Mixed planting of a legume cover crop might influence the soil nutrition by N₂ fixation. The percentage of the MBN in the total N in the plantation plots was lower than that of the MBN in the total N in the secondary forest plot because the rate of decrease in MBN was higher than that in the total N due to clear-cutting and plantation.

View full abstract

The sustainability of intensive land use that was recently introduced to southwestern Ghana is discussed, based on field observations and interviews within a forestry project. Cocoa, a major crop in Ghana, was traditionally cultivated under natural shade trees, forming a forest-like landscape. However, due to land shortage and the introduction of modern farming systems, these shade trees now tend to be removed from the cocoa farms, leaving a high-input full-sun farming system, which is less sustainable. Moreover, a recent trend toward tree plantations is growing especially in areas damaged by wildfires. While this will increase the timber resources and improve farmers’ livelihoods in some cases, the negative impacts include a decrease in biodiversity and an increase in land conflicts. To secure the sustainability of land use, forest resources should be more integrated into farming systems. The government should strengthen the extension services and improve administrative regulations. At the field level, the planting of shade trees and small-scale plantations by farmers should be promoted, and the land tenure issues resulting from tree plantations should be monitored.

View full abstract

The cultivation fields of tea trees, the so-called ‘miang tea gardens’, are scattered in the forested area of the mountainous region of northern Thailand. The ‘miang tea garden&rsquo system has been evaluated as a successful form of ‘agroforestry&rsquo and ‘community forest management&rsquo. This paper aims to elucidate the process of changes involved in the management system of miang tea gardens in the last three decades from 1970 to 2002 when land-use and the subsistence were completely different. The study was conducted at the PMO miang village where had been researched in 1970 by Keen, one of the socio-economic researchers. As of September 2002, PMO village consisted of 32 households with a population of 87; 30 households were earning their livelihood through miang tea gardens management and miang production. The field survey was conducted between February and November 2002 and between July and August 2004, using interactive questioning to interview all the households who managed the miang tea gardens. Prior to 1970, forest materials except for tea trees had been utilized and managed by the village as co-managed resources. In the 1970s, an increase in the cultivation of tea tree seedlings led the villagers to set up borders for each garden; this was done to define the usufruct of each seedlings. Thus, the usufruct of forest materials, including tea trees, was confined to the relevant user of the garden. From the late 1980s onwards, following the decline of the miang market, the villagers began to introduce other crops in their gardens. This land-use change allowed the villagers to recognize their gardens as cultivation fields. Thus, the resources comprising their gardens were emphasized its conceptual characteristic as the ‘property managed by an individual for each subsistence activity&rsquo. In conclusion, it is indicated that the villagers should adopt changes in the management system and the conceptual characteristic of miang tea gardens, induced by the villagers themselves, as strategies for maximal utilization of their gardens as cultivation fields.

View full abstract