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PMAS Arid Agriculture University Rawalpindi (2015)

SIMULATION OF SOIL PROPERTIES AND CROP YIELD UNDER CONVENTIONAL AND CONSERVATION TILLAGE IN DRYLAND POTHWAR

SHARIF, MUHAMMAD

Titre : SIMULATION OF SOIL PROPERTIES AND CROP YIELD UNDER CONVENTIONAL AND CONSERVATION TILLAGE IN DRYLAND POTHWAR

Auteur : SHARIF, MUHAMMAD

Université de soutenance : PMAS Arid Agriculture University Rawalpindi

Grade : Doctor of Philosophy (PhD) 2015

Résumé partiel
Soil degradation and increasing cost of inputs are serious challenges for crop production in dryland Pothwar, Pakistan. Conservation tillage is advocated worldwide to improve soil properties and reduce input costs for sustainable dryland crop production ; however their effects on soil properties depend on site, climate and length of use. Computer based models are robust tools to estimate long-term changes in soil properties under different crop and soil management scenarios. Among these, CENTURY model is widely used to simulate soil organic carbon (SOC) and crop production, however literature on the performance of conservation tillage and CENTURY model under agro-climatic conditions of dryland Pothwar, Pakistan is scarce. Therefore, a two-year field study was carried out at University Research Farm, Chakwal Road, of PMAS-Arid Agriculture University Rawalpindi. The objectives were i) to compare traditional and alternative tillage practices for their effects on biochemical and physical properties of soil ii) to evaluate conservation tillage system against conventional practices for wheat yield and economic benefit iii) to validate CENTURY agro ecosystem model for long term simulation of different soil management practices under agro-climatic conditions of Pothwar. Treatments were applied in split-plot design keeping tillage practices in main-plots while residue management in sub-plots. The tillage treatments were a) conventional tillage (CT), moldboard ploughed at monsoon start and cross cultivation after each rainfall, b) minimum tillage (MT), moldboard ploughed at start of monsoon and two cross cultivations during fallow, c) reduced tillage (RT), chisel ploughed at monsoon start, weed controlled by chemical and wheat sown with zero drill, d) zero tillage (ZT), no tillage applied during fallow and summer weeds were controlled through chemical herbicide and wheat sown with zero drill. Sub-plot treatments were residue retained (+R) and removed (-R). During winter season, wheat crop was grown in all plots. The SOC stock and its fractions were significantly improved by ZT and RT with retention of crop residues. The values for MBC, POC, SOC were 0.95 Mg ha-1, 4.54 Mg ha-1 and 15.84 Mg ha-1 under ZT and 0.81 Mg ha-1, 4.08 Mg ha-1and 14.21 Mg ha-1 under RT. Similarly ZT and RT with residue had 37% and 34% higher water stable aggregates than CT without crop residue retention. As regards soil physical properties, CT and RT reduced the bulk density, enhanced infiltration and profile water content compared with ZT.

Présentation (Pakistan Research Repository)

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Page publiée le 7 mai 2019