MAIZE RESPONSE TO SOIL CONDITIONING AND IRRIGATION REGIMES

Abstract

Water scarcity and marginal soil fertility are the main concern of arid and semi-arid region of the world. In order to improve the physical conditions of soil and provide conducive environment for the growth and development of crops, soil conditioners are used. These soil conditioners also have the capability to increase the water holding capacity of soil and improve irrigation efficiency. The present study was undertaken to evaluate the effect of irrigation regimes and soil conditioners on the performance of maize crop. Four irrigation regimes ranging from 3-6 irrigation in relation to the critical stages of maize crop were applied. In case of six irrigations (W6) each irrigation was applied at emergence + 4 leaves + 8 leaves + tassel visible + blister and dough. Five irrigation (W5) at all above with exception of dough (one missing irrigation), four (W4) irrigation given at first four stages but omitting at blister + dough while W3 is three irrigations given only emergence + 4 leaves + 8 leaves (omitting irrigation tassel visible + blister + dough stage). Each irrigation was consists of 93 mm water. Three organic soil conditioners viz., farmyard manure (10000 kg ha-1), crop residue (10000 kg ha-1) and two levels of humic acid (2 and 4 kg ha-1), alone and in combinations with gypsum (1000 kg ha-1) as inorganic soil conditioner were applied a weak before sowing of maize. Maize variety Azam was sown on June 20th and 22nd on year 2011 and 2012 respectively at Agronomy Research Farm, The University of Agriculture Peshawar in Randomized complete block design with split arrangement having three replications. Irrigations regimes were allotted to main plots while soil conditioners to subplots. Results of the two years study revealed that with the exception of ear plant-1, plants at harvest and harvest index all vegetative and yield parameters were significantly affected by irrigation regimes. Mean crop growth rate was higher (28 %) with W5 as compared with other irrigation regimes. Comparing the effect of irrigation regimes between W3-W5 significantly (p≤0.05) higher leaf area plant-1 (5.4 %), leaf area index (6.5 %), weeds density m-2 (23 %) and extended grains filled duration (3 days) at W5 as compared with lower irrigation regimes. When comparison was made between all six irrigation regimes significantly heavier grains, taller plant height (7 %), higher rows ear-1 (26 %), grains ear-1 (14 %), grain yield (3851 kg ha-1) and biological yield (10653 kg ha-1) were found in five times irrigated plots as compared with lower irrigation regime while higher grain N contents (15 %) and straw N contents (24 %) were observed at six irrigation regimes. Maximum irrigation (W6) did not significantly increased plant height, crop growth rate, grains ear-1, rows ear-1, biological yield and grain yield as compared with W5 however W6 significantly delayed maturity. Omission of single irrigation at blister stage (between W5 – W4) reduced thousand grain weight (5 %), biological yield (12 %) and grain yield (10 %). While in case of irrigation omission at dough stage (between W6 – W5) the reduction in thousand grains weight (6 %), biological yield (9 %) and grain yield (7 %) were recorded. The results further showed that soil moisture contents significantly increased while significant reduction in soil bulk density were recorded with increase in irrigation application. Improved soil water relation through application of soil conditioners can improve the yield and yield components of maize. Results showed that growth characteristics of maize were significantly affected by soil conditioners (SC). Application of crop residue as SC resulted in higher: emergence (17), soil moisture (28 %) compared with other SC. Farmyard manure application had resulted in significantly higher average crop growth rate (15 g m-2 d-1), leaf area (4449 cm2), leaf area index (4.49) and weed density m-2 (39 %) as compared to control treatments. Farmyard manure incorporation produced significantly taller plants (207 cm) having maximum grains ear-1 (403 ) with heavier grain (282.21 g), grain yield (4476 kg ha-1), biological yield (11470 kg ha-1), harvest index (40 %), grain N (22.7 g kg-1) and straw N (10.3 g kg-1) as compared to other soil conditioners and control treatments. The higher level of humic acid (4 kg ha-1) significantly delayed tasseling (6 days), silking (7 days), maturity (10 days) with extended period of grain filling duration (2 days) as compared to control and other SC application. Soil analysis after the harvest of the crop showed that FYM treated plots had significantly maximum total soil N, organic carbon with lowest bulk density than in control plot. Data on the effect of gypsum application as sole or in combination with the other SC reveals that addition of gypsum had significantly increased all parameters except weed density m-2, ear plant-1, grains ear-1, and bulk density as compared with no G application. Gypsum along with HA at the rate of 4 kg ha-1 application was able to delayed tasseling, silking, grain filled duration and maturity while maximum crop growth rate, leaf area, leaf area index, weed density, grain yield biological yield grain, straw, soil N contents, organic carbon and minimum bulk density was observed in G x FYM. In case of W x SC maximum leaf area and leaf area index, plant height, thousand grain weight and grain yield were recorded with increase in irrigation from three to five. Combined application of G x FYM having water application up to W5 (Blister stage) produced more grain yield as compared with other combinations. It is concluded that farmyard manure (10 tons ha-1) and gypsum (1 tons ha-1) with five irrigations at the known critical stages (at emergence, 4 leaves, 8 leaves and tassel visible and blister) can performed better as compared with other treatments applied for obtaining higher growth and productivity of maize crop in Khyber Pakhtunkhwa, Province, Pakistan.