Bruce A. McKenzie

Water-use efficiency and the effect of water deficits on crop growth and yield of Kabuli chickpea ( Cicer arietinum L.) in a cool-temperate subhumid climate

The present study was conducted from 1998 to 2000, to evaluate seasonal water use and soil-water extraction by Kabuli chickpea (Cicer arietinum L.). The response of three cultivars to eight irrigation treatments in 1998/99 and four irrigation treatments in 1999/2000 at different growth stages was studied on a Wakanui silt loam soil in Canterbury, New Zealand. Evapotranspiration was measured with a neutron moisture meter and water use efficiency (WUE) was examined at crop maturity. Water use was about 426 mm for the fully irrigated treatment and at least 175 mm for the non-irrigated plants. There was a significant correlation (P<0.001) between water use and biomass yield (R2=0.80) and water use and seed yield (R2=0.75). There were also highly significant (P<0.001) interacting effects of irrigation, sowing date and cultivar on WUE and the trend was similar to that for seed yield. The estimated WUE ranged from 22–29 kg DM/ha per mm and 10–13 kg seed yield/ha per mm water use. The three chickpea cultivars were capable of drawing water from depths greater than 60 cm. However, most of the water use (0.49–0.93 mm/10 cm soil layer per day) came from the top 0–30 cm, where most of the active roots were concentrated. The study has shown that using actual evapotranspiration and water-use efficiency, the biomass yield and seed yield of Kabuli chickpeas can be accurately predicted in Canterbury. Soil water shortage has been identified as a major constraint to increasing chickpea production. Drought was quantified using the concept of maximum potential soil moisture deficit (Dpmax) calculated from climate data. Drought responses of yield, phenology, radiation use efficiency and yield components were determined, and were highly correlated with Dpmax. The maximum potential soil moisture deficit increased from about 62 mm (irrigated throughout) to about 358 mm (dryland plots). Chickpea yield, intercepted radiation and the number of pods per plant decreased linearly as the Dpmax increased. Penman’s irrigation model accurately described the response of yield to drought. The limiting deficit for this type of soil was c. 165 and 84 mm for the November and December sowings in 1998/99 and 170 mm in 1999/2000. Beyond these limiting deficits, yield declined linearly with maximum potential soil moisture deficits of up to 358 mm. There was little evidence to support the idea of a moisture sensitive period in these Kabuli chickpea cultivars. Yield was increased by irrigating at any stage of crop development, provided that the water was needed as determined by the potential soil moisture deficit and sowing early in the season.

Growth, yield and water use of lentils (Lens culinaris) in Canterbury, New Zealand.

Lentils ( Lens culinaris Medik.) were sown on eight sowing dates from April to November in two seasons in Canterbury, New Zealand. In 1984/85, six sowing dates were combined with two lentil cultivars (Olympic and Titore) and two irrigation treatments. In 1985/86, Titore was sown on two dates, with four irrigation treatments. An additional experiment grown under rain shelters examined the response of Titore to four irrigation regimes. The 1984/85 season was dry and rainfall was only 70% of the long-term mean. In this season, seed yield was high, 3·3 t/ha from the May sowing. The 1985/86 season was wetter than average and seed yields were lower, ranging from 0·6 to 1·5 t/ha. Under rain shelters, seed yield ranged from the equivalent of 0·32 to 2·5 t/ha. Sowing date had the most marked effect on seed yield. In the 1984/85 season, all autumn and winter sowings yielded 2·4–3·3 t/ha, whereas the spring sowings yielded 0·5–1·5 t/ha. In 1985/86, unirrigated plots from the May sowing yielded 1·5 t/ha, whereas all other plots yielded c . 0·8 t/ha. Generally, the small-seeded cultivar Titore outyielded Olympic. Dry matter (DM) accumulation followed similar trends to seed yield. Seasonal DM accumulation followed a sigmoidal curve. Functional growth analysis indicated that plants from autumn/winter sowings had a weighted mean absolute growth rate of 110–171 kg/ha per day, whereas spring-sown plants grew at 96–137 kg/ha per day. The maximum crop growth rate was 230 kg/ha per day in the July 1984 sowing. There was little positive response to irrigation in both seasons. Under rain shelters, there was a linear increase in both dry matter and seed production with increased total water. Fully irrigated plants produced 1·27 g DM and 0·72 g seed/m 2 per mm of water received. In the field experiments there was no relationship between maximum potential soil moisture deficit (D) and yield. Under rain shelters, however, there was a linear relationship which indicated a limiting deficit of c . 130 mm. The relationship showed that, for each millimetre increase in D above D 1 , 0·39% of the maximum yield was lost. Under the rain shelters, there was a strong relationship between yield and actual evapotranspiration (ET). Water-use efficiency (WUE) ranged from 2·81 g DM/m 2 per mm ET in unirrigated plots to 0·69 g seed/m 2 per mm ET. The results showed that lentil growers in Canterbury, and presumably in similar environments, are unlikely to benefit from irrigating their crops. In such environments, lentils appear to be an ideal dryland crop.

Variability in yield of four grain legume species in a subhumid temperate environment. I. Yields and harvest index

SUMMARY In 1998/99 and 1999/2000, field trials were conducted to try to explain why grain legume yields and harvest index are more variable than many other crops. Treatments involved varying plant populations and sowing depths and were selected to maximize plant variability. Both yields and harvest index were variable. Total dry matter (TDM) production generally increased as plant population increased up to twice the optimum population. Increases ranged from 80 to 130 % with lupins producing the highest yields of 878 and 972 g/m 2 of TDM in 1998/99 and 1999/2000 respectively. While plants sown at 10 cm depth produced more TDM than did plants sown at 2 cm, the difference was only 3 %. Seed yields followed similar trends to TDM, with maximum yields (mean of 403 g seed/m 2 ) produced at twice the optimum population. Crop harvest index (CHI) was quite variable and ranged from 0 . 31 to 0 . 66. Crop HI was lowest (0 . 43) at the lowest population and increased to 0 . 55 at twice the optimum plant population. In both seasons, lentil had the highest CHI and lupin the lowest. While CHI was variable there were very close relationships between seed yield and TDM which suggested that maximum seed yield depends on maximizing TDM production. The results also suggest that growers should increase population by a factor of two to obtain maximum seed yields.

Influence of sowing date and irrigation on the growth and yield of pinto beans ( Phaseolus vulgaris ) in a sub-humid temperate environment

SUMMARY The growth and yield of pinto beans (Phaseolus vulgaris L.) cv. Othello in response to a total of six sowing dates (from October to December) and irrigation was examined over two seasons in Canterbury, New Zealand. In 1994}95, two irrigation treatments (nil and full) were combined with two sowing dates (27 October and 24 November). In 1995}96, Othello was examined under two irrigation treatments (nil and full) and four sowing dates (1 November, 15 November, 29 November and 13 December). The total rainfall for the two seasons was 50% and 60% of the long-term average, respectively. The mean temperatures for the seasons were similar to the long-term average. Both irrigation and sowing date had a marked eect on growth and seed yield. Averaged over both seasons, seed yield for fully irrigated crops was 337 g}m#, c. 50% higher than the yield of unirrigated crops. The irrigated crops yielded more than the unirrigated crops because they attained greater canopy closure, intercepting 84‐95% of incident radiation. They also had on the average 47% higher leaf area duration (LAD), 72% higher maximum leaf area index (LAI) and greater utilization coecient. The mid- to late November-sown crops yielded more than the late October to early November and December-sown crops because the leaf area of the former increased most rapidly, achieved a higher maximum LAI and LAD and consequently intercepted more photosynthetically active radiation (PAR). They also had faster pod growth rates and 26% of stored assimilates contributed to pod growth compared with 13% in late October to early November and 5% in December-sown crops. The results showed that pinto beans can grow and yield well in Canterbury, and that a yield advantage could be obtained when sown in mid- to late November and with irrigation.

Variability in yield of four grain legume species in a subhumid temperate environment. II. Yield components

SUMMARY The effects of plant population (one-tenth of the optimum to four times the optimum populations in 1998/99 and 10–400 plants/m 2 in 1999/2000) and sowing depth (2, 5 and 10 cm) on yield and yield components of four grain-legumes (Cicer arietinum, Lens culinaris, Lupinus angustifolius and Pisum sativum) were studied. Seed yields were strongly positively correlated with the number of pods and seeds/m 2 in both years in all species. The mean seed weight and number of branches/plant were inversely related to plant population. There was a nearly six-fold reduction in the number of branches/plant as plant population increased, which was due to restricted branching, and not to branch senescence. Generally, the variation in yield components was species dependent. However, for all species the number of pods/m 2 and seeds/m 2 could be used as primary criteria for selection in a breeding programme.

Light interception and utilization of four grain legumes sown at different plant populations and depths

SUMMARY Canopy development, radiation absorption and its utilization for yield was studied in four grain legume species Cicer arietinum, Lens culinaris, Lupinus angustifolius and Pisum sativum. The grain legumes were grown at different plant populations and sowing depths over two seasons in Canterbury, New Zealand. The green area index (GAI), intercepted radiation, radiation use efficiency (RUE) and total intercepted photosynthetically active radiation (PAR) increased significantly (P<0.001) with increased plant population. Narrow-leafed lupin produced the highest maximum biomass (878 and 972 g/m 2 , averaged over all populations during 1998/99 and 1999/2000, respectively) and intercepted more radiation (600 and 714 MJ/m 2 , averaged over all populations during 1998/99 and 1999/2000, respectively) than the other three legumes. In all four species, in both trials, the highest plant populations reached their peak GAI about 7–10 days earlier than legumes sown at low populations. Cumulative intercepted PAR was strongly associated with seed yield and crop harvest index (CHI). The RUE increased (from 1 . 10 to 1 . 46 and from 1 . 04 to 1 . 34 g/MJ during 1998/99 and 1999/2000, respectively) as plant population increased and was highest in the highest yielding species (e.g. 146 and 1 . 36 g/MJ for narrow-leafed lupin in both experiments). The larger leaf canopies produced at the higher plant populations reduced the extinction coefficient (k). The results suggest that in the subhumid temperate environment of Canterbury, grain legume species should be selected for the development of a large GAI. This should maximize PAR interception, DM production and, consequently, seed yield.

Growth and yield of two chickpea (Cicer arietinum L.) varieties in Canterbury, New Zealand

Abstract Growth and yield of chickpeas (Cicer arietinum L.) was examined over two growing seasons (1990–91 and 1991–92) in Canterbury, New Zealand. The 1990–91 season was very suitable for chickpea growth and the seed yield was high at 345 g/m2. The 1991 ‐92 season was less suitable and seed yield was lower at only 187 g/m2. In both growing seasons the application of nitrogen (N) fertiliser increased seed yields, with 50 kg N/ha giving a 17% increase in 1990–91 and 100 kg N/ha giving a 43% yield increase in 1991 ‐92. Inoculation with Rhizobium had no effect on yield. There was no benefit from increasing plant population, even though higher plant populations intercepted more solar radiation. This was primarily because of a reduced number of pods/plant at the higher plant populations. Response to sowing date suggests that spring sowings will be the highest yielding. Crops sown in winter yielded up to 700 g dry matter (DM)/ m2, but harvest index (HI) was low at only 0.25. The spring sowing produced 210 g see...

Environmental control of lentil (Lens culinaris) crop development

The lentil ( Lens culinaris Medik.) cultivars Titore and Olympic were sown at Canterbury, New Zealand, on eight dates, from April to November in 1984 and in May and August in 1985. Of the four important physiological growth stages (sowing to emergence (S–E), emergence to flowering (E–F), flowering to physiological maturity (F–P m ) and physiological maturity to harvest (P m –H)), the duration of all except E–F depended upon accumulated thermal time above 2 °C. The mean accumulated thermal times for E–F, F–P m , P m –H were 116, 565 and 293 °C days, respectively. Stage E–F required from 1165 °C days for an April sowing to 509 °C days for a November sowing. There was a highly significant positive relationship ( r 2 = 0·99) between the rate of development during E–F and mean temperature. Photoperiod also affected development rate. Neither of the two cultivars studied had a vernalization requirement for the induction of flowering. In both years, the development rate during E–F was highly dependent upon photoperiod-corrected temperature. The relationships presented show that development of lentil crops in Canterbury can be accurately predicted using accumulated temperature and photoperiod-corrected temperature.

Intercepted radiation and yield of lentils ( Lens culinaris ) in Canterbury, New Zealand

Lentils were grown in 1984/85, 1985/86 and 1988/89 in Canterbury, New Zealand. Results showed that lentil canopies were capable of intercepting a maximum of 95 % of incident solar radiation at a leaf area index of 7. Autumn sowings attained canopy closure, but late spring sowings did not. At the highest population density used (500 plants/m 2 ), only 65 % of incident solar radiation was intercepted by a late spring-sown crop

The effect of irrigation and sowing date on crop yield and yield components of Kabuli chickpea (Cicer arietinum L.) in a cool-temperate subhumid climate

The canopy development, radiation absorption and its utilization for biomass production in response to irrigation at different growth stages of three Kabuli chickpea ( Cicer arietinum L.) cultivars was studied on a Wakanui silt loam soil in Canterbury, New Zealand (43°38S, 172°30E). The study also aimed at quantifying the yield potential of the crop under varying irrigation regimes and sowing dates. Green area duration (GAD), intercepted radiation ( F i ), radiation use efficiency ( U ) and total intercepted PAR were significantly ( P R 2 =0·69–0·83) with GAD than seed yield ( R 2 =0·60–0·69). Accumulation of TDM was highly related to intercepted PAR. Fully irrigated November-sown crops had a final U of 1·46 g DM/MJ PAR. The unirrigated crop had a U of only 0·92 g DM/MJ PAR. The U tended to decrease with delayed sowing. Averaged over the 2 years, irrigation increased seed yield by 74–124% and trends were similar for TDM yield. Seed yield was doubled in November-sown chickpeas (4·6 t/ha) and cv. Sanford produced 14 and 16% more seed than cvs Dwelley and B-90 respectively. Full irrigation from emergence to physiological maturity always gave the highest seed yield (>4·7 t/ha), and there was no indication of a critical period of sensitivity to water stress. Based on results collected in the first growing season a simple model relating seed yield to radiation interception, U and HI was made. Results from the second growing season were then used as a simple verification to test the accuracy of predictions. The results suggest that these varieties have the potential to yield more than 4·5 t/ha of seed in Canterbury.