Soil Chemical and Biological Activities under Vegetable Intensive Colocasia-based Cropping System in Indian Sub-Himalayas

ABSTRACT

Lack of crop diversification with suitable vegetable-based cropping system is a major constraint in limiting the productivity and sustainability of north-western Indian sub-Himalayas. To find out a sustainable vegetable-based cropping system in this region, a three year colocasia-based vegetable intensive experiment was conducted at Hawalbagh, Almora, India in a sandy clay loam soil under sub-temperate climatic conditions. Seven colocasia-based vegetable cropping systems along with rice–wheat system were compared under recommended package and practices. The system productivity in terms of colocasia equivalent yield was highest under colocasia–onion–frenchbean (52.38 Mg ha^?1) system. Sustainable yield index was highest with colocasia–gardenpea–frenchbean system (0.86). After 3 years, total soil organic carbon (0–5%), available N (2–22%), P (–7% to 14%) and K (3–15%) concentrations were increased in all cropping systems except rice–wheat system, where negative balance of available P (7%) was observed over that of initial soil. Significantly higher soil microbial activity, soil carbohydrate, dehydrogenase, protease, acid and alkaline phosphatases activity were observed under colocasia–onion system. The results suggest that colocasia–onion–frenchbean system with higher productivity improves soil fertility and enhances enzymatic activities.     

一氧化氮和繁殖控制

一氧化氮 (NO) ,被认为是动物体内重要的生物信使。NO是由 L -精氨酸在 NO合成酶的作用下合成的。NO合成酶在许多哺乳动物细胞中都有大量的同分异构体。近几年的研究结果表明 ,NO对繁殖功能的许多方面都有很大的影响。NO可控制下丘脑和垂体水平上的促性腺激素的分泌、LH峰的机制、性行为、性激素的合成、卵泡存活和排卵。本文对 NO控制下丘脑 -垂体 -性腺轴的关键分子机理进行综述     

Minimum light intensity threshold to prevent negative effects on broiler production and welfare

1. Research focused on lower light intensity levels is required to set minimum standards appropriate for production and welfare of intensively housed broilers. The objective of this research was to study light intensity (0.1 to 10 lx) effects on Ross × Ross 308 and 708 genotypes.

2. Three experiments (35 d each) using 18 720 broilers were conducted with the initial experiment using two replicates of 0.1, 1, 5 and 10 lx. The second and third experiments examined 0.5, 1, 5 and 10 lx with treatments replicated twice in each experiment in a randomised complete block design with experiment acting as a block. In each experiment, mixed sex broilers from each genotype were housed in 6 equally sized pens per room.

3. In Experiment 1, the introduction of 0.1 lx at d 7 caused high levels of mortality and poor growth rate from d 7 to 14 and was discontinued.

4. In Experiments 2 and 3, increasing light intensity increased body weight gain (0–35 d) and feed intake (0–35 d) in a quadratic and linear fashion, respectively. Similarly, mortality corrected gain to feed ratio (FCR, 0–35 d) demonstrated a quadratic response with a maximum at 5 lx. Carcass, breast meat and skin, abdominal fat and drum skin, as a percentage of live weight, increased while drum bone and wing yield decreased in a linear fashion with increasing light intensity. Total carcass composition was unaffected by light intensity.

5. Genotype effects were numerous. No interactions were found between genotype and light intensity.

6. Ocular dimensions and the incidence of foot pad lesions decreased in a quadratic and linear fashion, respectively, with increasing light intensity. In contrast, welfare-associated gait score and mortality levels were not affected by light intensity.

7. It was concluded that performance, breast meat yield and bird welfare improved with increasing light intensity. The data support 5 lx as a minimum light intensity in broiler production.     

Critical Toxic Ranges of Chromium in Spinach Plants and in Soil

ABSTRACT

Long-term irrigation with untreated industrial sewage effluents causes accumulation of high concentrations of chromium (Cr) and other heavy metals in soil and subsequently in crop plants (especially leafy vegetables), which can be phytotoxic to plants and/or a health hazard to animals and humans. Greenhouse experiments were conducted to determine the effects of Cr application on the growth of spinach (Spinacia oleracia L.) and to develop critical toxic ranges of Cr in plants and in soil. The study involved growing of spinach variety ‘Punjab Green’ in a greenhouse on silty clay loam and sandy soils equilibrated with different levels of applied Cr (0, 1.25, 2.5, 5, 10, 20, 40, 80, 160, and 320 mg Cr kg^{? 1} soil). Plants were harvested at: three growth stages 45, 60, and 90 days after sowing (DAS). Critical toxic ranges were estimated by regressing and plotting data on ammoniumbicarbonate-diethylenetriaminepenta-acetic acid (AB-DTPA) extractable Cr in soil or Cr concentration in plants versus dry-matter yield (DMY) of spinach at the three growth stages. Toxic ranges, i.e., slightly toxic (80%–90%), moderately toxic (70%–80%), and extremely toxic (< 70%) in terms of DMY relative to the attainable maximum DMY, were established for both soils and for plants at all three growth stages. There was no germination of spinach with applied Cr at 320 mg Cr kg^{? 1} rate in silty clay loam soil and at 40 mg Cr kg^{? 1} rate in sandy soil due to Cr toxicity. Roots accumulated more Cr in comparison with shoots. Chromium concentrations of 0.47–1.93 mg Cr kg^{? 1} soil in silty clay loam soil, 0.13–0.94 mg Cr kg^{? 1} soil in sandy soil, 1.08–5.40 mg Cr kg^{? 1} plant DM in silty clay loam soil and 0.54–11.7 mg Cr kg^{? 1} plant DM in sandy soil were found to be toxic. The critical toxicity ranges of Cr thus established in this study could help in demarcating Cr toxicity in soils and in plants such as spinach and other leafy vegetables due to irrigation of soils with untreated sewage water contaminated with chromium.     

Impacts of Bioinoculants Pseudomonas jesenii MP1 and Rhodococcus qingshengii S10107 on Chickpea (Cicer arietinum L.) Yield and Soil Nitrogen Status

Cold-adapted bioinoculants are considered as harbingers of sustainable hill agriculture. Therefore, two previously characterized psychrotolerant diazotrophs, Pseudomonas jesenii MP1 and Rhodococcus qingshengii S10107, were evaluated for their plant growthpromoting potential for chickpea (Cicer arietinum L.) grown under natural field conditions. Comparative analysis of agronomical and biochemical crop parameters revealed the irrelevance of chemical fertilizers for chickpea production; the diazotrophs alone were sufficient to fulfil the crop''s nutritional requirement. However, the integrated use of bacterial strains in combination with urea at 20 kg N ha^-1 as urea was being recommended for higher crop yield and better soil nitrogen status. Quantitative polymerase chain reaction (qPCR) and denaturing gradient gel electrophoresis (DGGE)-based soil bacterial dynamics unveiled the persistence of both diazotrophs until the end of the crop maturation period without affecting the native micro-flora. Therefore, these bioinoculants can be explored as natural nitrogen resource, and an additional incentive in their bio-formulation will be a step towards agricultural sustainability.     

The potential of small ruminant farming as a means of poverty alleviation in rural southern India

Small ruminant production has the potential to address the global challenge of greatly increased food production in impoverished rural areas in a manner that is socioeconomically sustainable and carbon efficient. Twenty-six small ruminant landless farmers in three villages in the Kanchipuram District of the state of Tamil Nadu were surveyed with regard to their sheep farming practice and production indices, with the preliminary aim of evaluating the potential of small ruminant farming in alleviating poverty in parts of rural in southern India. The small ruminant farmers reared mostly indigenous Madras Red sheep as a means of generating primary or supplementary income. Participatory interviews were undertaken to enable the completion of a questionnaire pertaining to sheep production over the four most recent annual production cycles (referred to as instances) at the time of the study. When calculating the annual farm profits without taking into consideration the opportunity cost of labour, 83% of annual sheep production cycles over a 4-year period added to household incomes. Further, 23% of the instances that accounted for the opportunity cost of labour, household income was raised above the Indian Government’s defined poverty line solely through small ruminant farming. Management practices were identified, while participating in landless farmer interviews provided an insight into the husbandry, or lack thereof, which resulted in low lambing percentages and rates of high ewe losses, perinatal lamb mortality and abortion. The study showed both the vulnerability and potential resilience of small ruminant farming to natural disaster, in this case catastrophic flooding in 2015. While small ruminant farming generated income in most instances, the way it is practiced creates opportunities for simple changes in husbandry and management that could make it more efficient in poverty alleviation.

     

Dynamic Oryza Genomes: Repetitive DNA Sequences as Genome Modeling Agents

Repetitive sequences, primarily transposable elements form an indispensable part of eukaryotic genomes. However, little is known about how these sequences originate, evolve and function in context of a genome. In an attempt to address this question, we performed a comparative analysis of repetitive DNA sequences in the genus Oryza, representing ~15 million years of evolution. Both Class I and Class II transposable elements, through their expansion, loss and movement in the genome, were found to influence genome size variation in this genus. We identified 38 LTRretrotransposon families that are present in 1,500 or more copies throughout Oryza, and many are preferentially amplified in specific lineages. The data presented here, besides furthering our understanding of genome organization in the genus Oryza, will aid in the assembly, annotation and analysis of genomic data, as part of the future genome sequencing projects of O. sativa wild relatives.