Environment and ecology

It is essential to find ways and mean to increase the yield and lessen the cost of production so that there is enough fruit production to meet the requirement of the consumers. The yearly growth of plants, excessive growth of weeds and production of fruits deplete the soil of its nutrient reserves resulting in reduction of native-soil fertility. Mulching of organic and inorganic materials create favourable conditions for getting maximum production of quality fruits on sustainable basis within the limits of soil, water and fertility management. There is a need to conserve soil moisture and reduce weed population for proper maintenance of soil moisture and fertility. Mulching is thus, one of the most important cultural practice which affects growth, yield and quality in fruit crops. Tree growth is greatly influenced by the use of different organic and inorganic mulching materials. They conserve soil moisture in the root zone of fruit trees. The presence of adequate moisture in the soil is vital for growth and physiological processes. Besides conserving moisture, mulching also prevents sudden and extreme temperature changes, reduces erosion by wind or water, checks surface run-off and suppresses the weed growth. The application of organic and inorganic mulches in fruit orchards create an additive effect by restricting the nutrient removal through weeds and ultimately creating favourable conditions for availability of nutrients for getting higher productivity of good quality fruits on sustainable basis.

	 

	Key words: Mulching, growth, fruit quality, yield, moisture conservation, weed control.

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Sustainable fruit production by soil moisture conservation with different mulches: A review

This study examined the effects of different soil texture configurations on water movement and solute transport to provide a reliable scientific basis for the application of negative-pressure irrigation (NPI) technology. HYDRUS-2D was used to analyze water movement and solute transport under NPI. The main results are as follows. (1) HYDRUS-2D can be used to simulate water movement and solute transport under NPI, as there was good agreement between the simulated and measured values for water contents, NaCl concentrations, and wetting distances in the horizontal and vertical directions; the Nash–Sutcliffe efficiency coefficients were in the range of 0.94–0.97. (2) Layered soils have obvious effects on water movement under NPI. With the emitter position in the loam layer, when a coarse texture of loamy sand was present below the loam layer (namely, L-LS), irrigation water accumulated in the topsoil, and this led to an increase in evaporation compared with the homogeneous loam profile. However, fine texture silty loam or silty clay loam layers beneath the loam layer (namely, L-SiL or L-SiCL, respectively) was more conducive to water infiltration into the lower layer, and this increased the amount of water infiltration and simultaneously reduced the surface evaporation effectively. (3) Layered soils have obvious effects on solute transport under NPI, and salt accumulation will readily occur in the clay-rich soil layer at the interface. The maximum soil salt accumulation of L-LS occurred above the soil interface between the two soil layers with a value of 21.8 g kg-1; however, for L-SiCL and L-SiL, the maximum salt accumulation occurred below the soil interface between the two soil layers, with values of 23.8 g kg-1 and 20.08 g kg-1, respectively. (4) Interlayered soils showed remarkable changes in the water infiltration characteristics and salt-leaching intensities under NPI, and the properties for the soil profile with a silty loam interlayer were better than those for the soil profile with a silty clay loam interlayer. The soil profile with a loamy sand interlayer had the lowest amount of water infiltration, which resulted in reductions of the salt-leaching intensities. Thus, NPI is clearly not suitable for loamy sand soil. Overall, the results demonstrated that soil texture configurations affected water movement and solute transport under NPI. Therefore, careful consideration should be given to the use of NPI to achieve target soil water and solution conditions and reduce water loss.

Simulations of water movement and solute transport through different soil texture configurations under negative‐pressure irrigation

Effects of different irrigation management parameters on cumulative water supply under negative pressure irrigation

Effect of organic and inorganic source of nutrients on growth, flowering, fruiting, yield and quality of mango (Mangifera indica L.) cv. amrapali under high density planting

Our objective was to examine the effect of plastic mulching, three soil matric potentials (SMP) treatments {I 1 (-20 kPa), I 2 (-40 kPa), and I 3 (-60 kPa)} and three fertigation levels {F 1 (100%), F 2 (80%), and F 3 (60%) recommended dose of fertilizer} under drip irrigation conditions for nutrient uptake, growth parameters and yield in guava plants. The experiments were set up in factorial randomized block design with eighteen treatment combinations. The experiments were conducted during the year 2012-13.  The investigation indicated that the plant canopy spread in (N/S and E/W) directions was greatly affected by different treatments. However, non-significant effects of interaction parameters were found on plant height, crop volume and plant girth.  The maximum yield was obtained in MI 2 F 2 (68.66 kg per plant and 22.86 t ha -1 ) followed by NMI 2 F 2 (66.50 kg per plant and 22.14 t ha -1 ) treatments. The maximum percentage of high quality (fruit levels A and B) were 48.2% and 50.1% in -40 kPa  irrigation treatment for mulch and no mulch conditions under 100% application of recommended dose of fertilizers. The varying range of leaf nutrients observed for different treatments of irrigation, fertigation and mulch is  1.26-1.74% N, 0.14-0.26% P, 0.44-0.88% K, 36.33-74.23 ppm Zn, 11.33-32.76 ppm Cu, 415.6- 557.3 ppm Fe, 26.80- 39.06 ppm Mn, 0.533-0.762 % Mg and 3.42-5.06% Ca. Based on the results above, it is recommended that controlling SMP between -40 kPa to -45 kPa at 0.2 m depth immediately under the drip emitter and fertilizer dose of 80% recommended dose of fertilizer can be used as an indicator for drip irrigation scheduling in semi-arid region of northwest India. Keywords: fertilizer application, irrigation strategies, pressure head, tensiometer, leaf uptake

Growth, yield and nutrient uptake of guava (Psidium Guavaja L.) affected by soil matric potential, fertigation and mulching under drip irrigation

Evolution of sequence-specific transcription factors clearly drives lineage-specific innovations, but less is known about how changes in the central transcriptional machinery may contribute to evolutionary transformations. In particular, transcriptional regulators are rich in intrinsically disordered regions that appear to be magnets for evolutionary innovation. The C-terminal Binding Protein (CtBP) is a transcriptional corepressor derived from an ancestral lineage of alpha hydroxyacid dehydrogenases; it is found in mammals and invertebrates, and features a core NAD-binding domain as well as an unstructured C-terminus (CTD) of unknown function. CtBP can act on promoters and enhancers to repress transcription through chromatin-linked mechanisms. Our comparative phylogenetic study shows that CtBP is a bilaterian innovation whose CTD of about 100 residues is present in almost all orthologs. CtBP CTDs contain conserved blocks of residues and retain a predicted disordered property, despite having variations in the primary sequence. Interestingly, the structure of the C-terminus has undergone radical transformation independently in certain lineages including flatworms and nematodes. Also contributing to CTD diversity is the production of myriad alternative RNA splicing products, including the production of “short” tailless forms of CtBP in Drosophila. Additional diversity stems from multiple gene duplications in vertebrates, where up to five CtBP orthologs have been observed. Vertebrate lineages show fewer major modifications in the unstructured CTD, possibly because gene regulatory constraints of the vertebrate body plan place specific constraints on this domain. Our study highlights the rich regulatory potential of this previously unstudied domain of a central transcriptional regulator.

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Aanchal Kumar Jain

Papers

Growth, yield and nutrient uptake of guava (Psidium Guavaja L.) affected by soil matric potential, fertigation and mulching under drip irrigation

The Cynosure of CtBP: Evolution of a Bilaterian Transcriptional Corepressor