A GIS based approach to modelling the effects of land-use change on soil erosion in New Zealand

Abstract. The problem of soil erosion is particularly evident in New Zealand, given the combination of coarse-textured soils, steep relief, high rainfall, and intensification of agriculture. A study was undertaken to assess the effects of land use change on soil erosion and sediment transport for the Ngongotaha catchment in New Zealand's North Island, using a GIS based decision support and modelling system. Model simulations considered the effect of increased catchment area under deer farming and forestry on the amount of sediment delivered to the catchment outlet, averaged over a period of six years. The simulations predicted that sediment loss from land under deer farming was considerably greater than from land under other livestock or forestry. Further model simulations testing best management practices demonstrated that sediment yield could be halved if deer farming was restricted to slopes under 20%.     

Identification of double/twin bolled and bicolor unit ‘cluster’ in <Emphasis Type="Italic">Gossypium hirsutum</Emphasis> L. cotton

Cultivated tetraploid Gossypium hirsutum L. (Malvaceae) cotton has been characterized as having one flower at a primordia. In a strain (CSH-13) of Gossypium hirsutum cotton, four plants out of 103 had two to three double bolls or twin bolls/plant during 2003–2004 crop season at CICR regional station, Sirsa, Haryana, India. Progeny evaluation in 2004 and 2005 crop seasons indicated that plants raised from seeds harvested from double bolls/twin bolls produced plants bearing double bolls only and plant progeny raised from the seed of single bolls from these mutant plants produced two to three double bolls per plant similar to the parent. Progeny testing revealed that double boll formation is the result of spontaneous mutation and environment does not influence its expression. The mutant is early in maturity by 10–15 days, naked seeded and possesses comparable agronomic characters with normal plants. Another spontaneous mutant of Gossypium hirsutum having more than three appendages originating from primordia.: four bolls one leaf, three bolls one leaf, two bolls two leaves, one boll three leaves were obtained from the population of CISV-13 strain in crop season 2003. These appendage groups have been described as bicolor unit by Clemens Bayer, [Zur Infloreszenzmorphologie der Malvales. Dissertations Botany 212 (1994)] and cluster mutant by Russell and Luther [J Cott Sci 6 (2002) 115]. One to three bolls in a cluster or bicolor unit were observed without formation of seeds and lint. About one-third of the total bolls on the mutant plant were of this type. In progeny testing during 2004 and 2005 crop seasons, this mutant produced plants exclusively with more than three appendages revealing that plants identified in 2003 were due to spontaneous mutation. This mutant was also early and naked seeded. Many of the other characters of the mutant plants were comparable with the wild type plants of the strain. Both the mutants were observed having economic impact due to their better yielding ability as compare to respective parents.     

Effect of gamma-irradiation on the lipid profile of nutmeg (Myristica fragrans Houtt.)

The effect of gamma-irradiation on the lipid constituents of nutmeg (Myristica fragrans) was examined at radiation doses between 2.5 and 10 kGy. The fatty acid composition of the triacylglycerol, the major lipid component, was found to be made up of myristic (90%), palmitic (6%), lauric (3%), petroselinic (0.13%), and stearic acids (0.5%) as determined by gas chromatography-mass spectrometry. A dose-dependent decrease in the triacylglycerol content and a concomitant increase in free fatty acids characterized the lipid profile of the irradiated spice. This suggested a breakdown of acylglycerols during radiation processing, resulting in the release of free fatty acids. These changes were found to be significant at doses above 5 kGy. The impact of the above changes on the flavor of the spice is discussed. These studies suggest that radiation processing of nutmeg should be limited to a dose of 5 kGy.     

Breeding distribution and maternal genetic lineages in Lulu,a dwarf cattle population in Nepal

Lulu is a dwarf cattle population bred in the Mustang district of western and central Nepal. This area is located around the habitat boundary between Bos taurus and Bos indicus. The peculiarities of Lulu are their small size (weight range in the adult female: 68–153 kg) and rearing in high mountain areas at 2800 m to 4000 m in altitude. There were 5770 head of Lulu cattle in the Mustang district in 1998, 4333 females and 1437 males. The morphological appearance of Lulu is Bos taurus. However, one of the five Lulu studied in Kagbeni, Mustang had a Bos indicus mitochondrial DNA type based on the D‐loop sequence, while the other four were Bos taurus. It is suggested that there are hybrids of Lulu with Bos indicus maternal lineage in a mostly taurine‐breed genetic background. Steps must be taken to preserve the unique Lulu.     

Effect of dietary Curcuma longa on enzymatic and immunological profiles of rohu,Labeo rohita (Ham.), infected with Aeromonas hydrophila

The aim of this study was to evaluate the dietary dosages of turmeric that enhance immune response and disease resistance against the opportunistic pathogens Aeromonas hydrophila in Labeo rohita fingerlings. Hence, four different dosages of turmeric at 0.1, 0.5, 1.0 and 5.0 g kg^?1 feed were given to the fingerlings of L. rohita for 60 days at 4% body weight. At every 20‐day interval, different biochemical, haematological, enzymatic and immunological parameters of fish were evaluated. After 60 days, fish were challenged with A. hydrophila. The mortality (%) was recorded on the tenth day post challenge. Most of the immune parameters including lysozyme activity, superoxide anion production and serum bactericidal activity were significantly (P<0.05) higher on 60 days of feeding of 1.0 g of turmeric per kg of feed. Challenge study indicated 100% and 89% survivability in the group of fish fed with 5.0 and 1.0 g of turmeric per kg of feed respectively. Feeding of turmeric might have maintained long‐term protection in fish by elevating the nonspecific immune system such as Nitroblue tetrazolium (NBT), lysozyme and serum bactericidal activity. The result showed that turmeric at a dose of 1.0 g kg^?1 feed for 60 days provided the greatest protection to pathogen challenge.     

Genetic variations in survival of rohu carp (Labeo rohita, Hamilton) after Aeromonas hydrophila infection in challenge tests

A challenge test against Aeromonas hydrophila was conducted using 2062 rohu carp (Labeo rohita) fingerlings obtained from 52 dams and 87 sires (87 full-sib families) of two year-classes (2003 and 2004). Attempts to establish a cohabitant challenge model were not successful. Therefore, fish were challenged by intraperitoneal injection with A. hydrophila in two replicate tanks per year-class, and dead fish were collected hourly. The mortality reached its peak at 16–22 h after challenge and had almost completely stopped after 58 h. The test was terminated after 382 h at which the average survival was 43.9 and 48.9% in the two 2003 year-class tanks, and 77.1 and 35.8% in the two 2004 year-class tanks. Heritability estimates for survival were obtained from sire and dam threshold models (THR) and sire and dam linear repeatability models (LINR). For both types of models the heritability estimates based on data from single tanks were not consistent. For both year-classes, data from one of the two challenged tanks demonstrated significant additive genetic variation in survival during the A. hydrophila infection, whereas the heritability estimates were not significantly different from zero for the other tank. Further, genetic correlation between survivals in the two replicate tanks in each year-class was not significantly different from zero. The differential results from the replicate tanks demonstrate that additional challenge test experiments are needed before firm conclusions can be drawn about the magnitude of additive genetic variation for survival to aeromonasis in rohu carp. A cohabitant challenge model that allows the testing of important defence mechanisms in the skin and mucous membranes of the fish might have been more appropriate. To establish a valid cohabitant challenge model for rohu carp should be given high priority.     

Stage Sensitivity of Mungbean (Vigna radiata L. Wilczek) to an Elevated Level of Carbon Dioxide

An experiment was undertaken using open‐top chambers to study the effect of CO₂ enrichment on crop growth and to assess the variation related to the time of CO₂ exposure. In general, enriched CO₂ conditions (600 ± 50 p.p.m.) in the chamber positively affected the growth and development of mungbean (Vigna radiata), a short‐duration (60–65 days) summer pulse crop. However, there was significant variability in the effect of the crop stage/time of CO₂ exposure. It was observed that high CO₂ exposure at an early growth stage [0–20 days after germination (DAG)] had a larger effect than that at a later growth stage (21–40 DAG). The experiment also provided a means of assessing the short‐ and long‐term effects of elevated CO₂ on the carbon exchange rate at both stages of exposure. The study revealed that the sensitivity of plants to high CO₂ was more pronounced with respect to net photosynthetic rate. The overall photosynthetic activity gave greater growth and development of plants under high CO₂.     

Effect of Lentil Residues on the Yield and Response of Succeeding Rice to Nitrogen

A field experiment was conducted at the Division of Agronomy, Indian Agricultural Research Institute, New Delhi during 1983-84 and 1984-85 to study the effect of lentil residues on the yield and response of succeeding rice to nitrogen. Lentil residues benefitted the succeeding rice and gave longer and heavier panicles, more grains per panicle, higher 1000-grain weight and higher grain and straw yield of rice as compared to fallow. Rice responded well to applied nitrogen both in the absence and presence of lentil residues. The effect of lentil root residues and root residues plus incorporation of lentil straw was equivalent to 11 and 33 kg N ha⁻¹ when 60 kg N ha⁻¹ was applied to rice; the corresponding values being 54 and 60 kg N ha⁻¹ when 120 kg N ha⁻¹ was applied to rice.     

Inheritance of congenital cataracts and microphthalmia in the Miniature Schnauzer

Congenital cataracts and microphthalmia in the Miniature Schnauzer were inherited as an autosomal recessive trait. Eighteen matings of affected X affected Miniature Schnauzers resulted in 87 offspring with congenital cataracts and microphthalmia (49 males/38 females). Two matings of congenital cataractous and microphthalmic Miniature Schnauzers (2 females) X a normal Miniature Schnauzer (1 male) yielded 11 clinically normal Miniature Schnauzers (7 males/4 females). Eighteen matings of congenital cataractous and microphthalmic Miniature Schnauzers (6 males) X carrier Miniature Schnauzers (9 females) produced 81 offspring; 39 exhibited congenital cataracts and microphthalmia (20 males/19 females) and 42 had clinically normal eyes (17 males/25 females).