In 2011/12 and 2012/13, eliminating tillage and retaining
residue did not have a significant impact on cassava, cowpea, or soybean yields in Nkhotakota or sweet potato and common bean
yields in Dowa (Table 7). Beans were planted late in Dowa in 2012/
13, and total rainfall from planting date to harvest was less than
180 mm. Pigeonpea yields were low in both districts, but greatest
when coppiced and allowed to re-grow in 2012/13 in Nkhotakota.
Continuous no-till maize yields were fairly consistent in Nkhotakota
and Dowa from 2011/12 to 2013/14, ranging from 3676 kg ha1
to 4364 kg ha1 (Table 8). In 2013/14, crop rotations increased maize yields to 5684 kg ha1 in CAR and 4789 kg ha1 in CTR in
Nkhotakota. In Dowa, crop rotations, regardless of tillage practice,
significantly increased maize yields and water-use efficiency
(WUE) compared to NTM. Water-use efficiencies were significantly
greater in Dowa than Nkhotakota every year. Using a general linear
model to analyze the effects of multiple factors on maize yields in
2013/14, only crop rotation had a significant impact (p = 0.016),
while cropping system (p = 0.055), tillage practice (p = 0.397),
residue retention (p = 0.075), and district (p = 0.115) did not
significantly impact maize yields.
In 2011/12 and 2012/13, no-till maize produced significantly
more protein than cassava, sweet potato, cowpea, soybean, or
bean, with or without pigeonpea intercropping, in Nkhotakota and
Dowa (Table 9). In 2013/14, protein production was similar among
all cropping systems in Nkhotakota and was significantly greater in
CAR than NTM in Dowa. Over the course of the 3-year study, NTM
produced significantly more protein than CTR in Nkhotakota and
CAR and CTR in Dowa.