Agriculture Reference
In-Depth Information
3000
2000
Y = -2610.23 + 5.5806X - 0.0013X
2
R
2
= 0.6011**
1000
0
1000
1500
2000
Shoot dry weight (kg ha
-1
)
FIGURE 1.9
Relationship between shoot dry weight and grain yield of dry bean.
200 kg N ha
−1
at all growth stages compared with lower N rates, except at 23 days growth stage.
The increase in shoot dry weight at 44 days growth was 184% with the application of 200 kg N
ha
−1
compared with without N application or control treatment. Similarly, the shoot dry weight
increase was 654% at 60 days after sowing, 392% at 78 days after sowing, and 453% at 92 days
after sowing with the application of 200 kg N ha
−1
compared with control treatment. It is reported
by Fageria (2002) that among all essential plant nutrients, N is quantitatively most important for
dry bean growth in most of the bean-producing regions around the world. N nutrition influences
leaf growth and leaf area duration, and hence the carbohydrate source size, the photosynthetic
rate per unit leaf area, and hence source activity, and the number and size of vegetative and
reproductive storage organs, and hence sink capacity (Marschner, 1995). Pelegrin et al. (2009)
studied the response of dry bean to N application on an Oxisol of central Brazil and reported
that the bean crop response to N was highly significant. The bean plant's efficiency in using N
fertilizer is rather low, being less than 70% of the applied fertilizer. The remaining fertilizer is
lost through volatilization and leaching, losses being greater with broadcast application (Thung
and Rao, 1999).
The variability in the shoot dry matter yield with N fertilization increased with the advancement
of plant age up to 78 days of plant growth (Table 1.9). Maximum variability in shoot dry weight
with N application was at 60 (83%) and 78 (84%) days plant growth (Table 1.9). This means that N
requirement for dry bean is maximum between 60 and 78 days growth period. The data in Table
1.9 also show that dry matter increase was slow between the 23- and 44-day growth period and it
was almost linear between 44 and 93 days plant growth. Shoot dry weight was having significant
quadratic association with the grain yield of dry bean (Figure 1.9). Hence, improving the shoot dry
weight is an important aspect in increasing the grain yield of this legume crop.
1.2.1.4 Panicle Number, Panicle Length, and Pod Number
Panicle density, panicle length, and pod number per unit area are important yield components in
cereals and legumes, respectively. These traits have a significant positive association with grain
yield in cereals and legumes (Fageria, 2007; Fageria and Santos, 2008). Figure 1.10 shows that the
grain yield of upland rice increased significantly and quadratically with increasing panicle density
of upland rice. Similarly, the grain yield of dry bean was having significant quadratic association
with pod number (Figure 1.11). The N and genotypes treatments and their interactions significantly
affected panicle number per pot and panicle length (Table 1.10). Panicle number varied from 3.7
to 10.3 per pot at low N level with an average value across the genotypes of 7.9 per pot. Similarly,
panicle number at higher N level varied from 14.3 to 29.0 per pot with an average value of 21.4 per
pot. Overall, the increase in panicle number per pot was 171% with the application of N as compared
to treatment without N fertilization. The number of panicles (X) were having significant (P < 0.01)
quadratic relationship with the grain yield (Y = −32.9349 + 7.2697X - 0.1467X
2
, R
2
= 0.81
**
). This
